NASM 0.98.25

[nasm.git] / preproc.c

/* preproc.c   macro preprocessor for the Netwide Assembler
 *
 * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
 * Julian Hall. All rights reserved. The software is
 * redistributable under the licence given in the file "Licence"
 * distributed in the NASM archive.
 *
 * initial version 18/iii/97 by Simon Tatham
 */

/* Typical flow of text through preproc
 *
 * pp_getline gets tokenised lines, either
 *
 *   from a macro expansion
 *
 * or
 *   {
 *   read_line  gets raw text from stdmacpos, or predef, or current input file
 *   tokenise   converts to tokens
 *   }
 *
 * expand_mmac_params is used to expand %1 etc., unless a macro is being
 * defined or a false conditional is being processed
 * (%0, %1, %+1, %-1, %%foo
 *
 * do_directive checks for directives
 *
 * expand_smacro is used to expand single line macros
 *
 * expand_mmacro is used to expand multi-line macros
 *
 * detoken is used to convert the line back to text
 */

#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>

#include "nasm.h"
#include "nasmlib.h"

typedef struct SMacro SMacro;
typedef struct MMacro MMacro;
typedef struct Context Context;
typedef struct Token Token;
typedef struct Blocks Blocks;
typedef struct Line Line;
typedef struct Include Include;
typedef struct Cond Cond;
typedef struct IncPath IncPath;

/*
 * Store the definition of a single-line macro.
 */
struct SMacro
{
    SMacro *next;
    char *name;
    int casesense;
    int nparam;
    int in_progress;
    Token *expansion;
};

/*
 * Store the definition of a multi-line macro. This is also used to
 * store the interiors of `%rep...%endrep' blocks, which are
 * effectively self-re-invoking multi-line macros which simply
 * don't have a name or bother to appear in the hash tables. %rep
 * blocks are signified by having a NULL `name' field.
 *
 * In a MMacro describing a `%rep' block, the `in_progress' field
 * isn't merely boolean, but gives the number of repeats left to
 * run.
 *
 * The `next' field is used for storing MMacros in hash tables; the
 * `next_active' field is for stacking them on istk entries.
 *
 * When a MMacro is being expanded, `params', `iline', `nparam',
 * `paramlen', `rotate' and `unique' are local to the invocation.
 */
struct MMacro
{
    MMacro *next;
    char *name;
    int casesense;
    int nparam_min, nparam_max;
    int plus;                   /* is the last parameter greedy? */
    int nolist;                 /* is this macro listing-inhibited? */
    int in_progress;
    Token *dlist;               /* All defaults as one list */
    Token **defaults;           /* Parameter default pointers */
    int ndefs;                  /* number of default parameters */
    Line *expansion;

    MMacro *next_active;
    MMacro *rep_nest;           /* used for nesting %rep */
    Token **params;             /* actual parameters */
    Token *iline;               /* invocation line */
    int nparam, rotate, *paramlen;
    unsigned long unique;
    int lineno;                 /* Current line number on expansion */
};

/*
 * The context stack is composed of a linked list of these.
 */
struct Context
{
    Context *next;
    SMacro *localmac;
    char *name;
    unsigned long number;
};

/*
 * This is the internal form which we break input lines up into.
 * Typically stored in linked lists.
 *
 * Note that `type' serves a double meaning: TOK_SMAC_PARAM is not
 * necessarily used as-is, but is intended to denote the number of
 * the substituted parameter. So in the definition
 *
 *     %define a(x,y) ( (x) & ~(y) )
 * 
 * the token representing `x' will have its type changed to
 * TOK_SMAC_PARAM, but the one representing `y' will be
 * TOK_SMAC_PARAM+1.
 *
 * TOK_INTERNAL_STRING is a dirty hack: it's a single string token
 * which doesn't need quotes around it. Used in the pre-include
 * mechanism as an alternative to trying to find a sensible type of
 * quote to use on the filename we were passed.
 */
struct Token
{
    Token *next;
    char *text;
    SMacro *mac;                /* associated macro for TOK_SMAC_END */
    int type;
};
enum
{
    TOK_WHITESPACE = 1, TOK_COMMENT, TOK_ID, TOK_PREPROC_ID, TOK_STRING,
    TOK_NUMBER, TOK_SMAC_END, TOK_OTHER, TOK_SMAC_PARAM,
    TOK_INTERNAL_STRING
};

/*
 * Multi-line macro definitions are stored as a linked list of
 * these, which is essentially a container to allow several linked
 * lists of Tokens.
 * 
 * Note that in this module, linked lists are treated as stacks
 * wherever possible. For this reason, Lines are _pushed_ on to the
 * `expansion' field in MMacro structures, so that the linked list,
 * if walked, would give the macro lines in reverse order; this
 * means that we can walk the list when expanding a macro, and thus
 * push the lines on to the `expansion' field in _istk_ in reverse
 * order (so that when popped back off they are in the right
 * order). It may seem cockeyed, and it relies on my design having
 * an even number of steps in, but it works...
 *
 * Some of these structures, rather than being actual lines, are
 * markers delimiting the end of the expansion of a given macro.
 * This is for use in the cycle-tracking and %rep-handling code.
 * Such structures have `finishes' non-NULL, and `first' NULL. All
 * others have `finishes' NULL, but `first' may still be NULL if
 * the line is blank.
 */
struct Line
{
    Line *next;
    MMacro *finishes;
    Token *first;
};

/*
 * To handle an arbitrary level of file inclusion, we maintain a
 * stack (ie linked list) of these things.
 */
struct Include
{
    Include *next;
    FILE *fp;
    Cond *conds;
    Line *expansion;
    char *fname;
    int lineno, lineinc;
    MMacro *mstk;               /* stack of active macros/reps */
};

/*
 * Include search path. This is simply a list of strings which get
 * prepended, in turn, to the name of an include file, in an
 * attempt to find the file if it's not in the current directory.
 */
struct IncPath
{
    IncPath *next;
    char *path;
};

/*
 * Conditional assembly: we maintain a separate stack of these for
 * each level of file inclusion. (The only reason we keep the
 * stacks separate is to ensure that a stray `%endif' in a file
 * included from within the true branch of a `%if' won't terminate
 * it and cause confusion: instead, rightly, it'll cause an error.)
 */
struct Cond
{
    Cond *next;
    int state;
};
enum
{
    /*
     * These states are for use just after %if or %elif: IF_TRUE
     * means the condition has evaluated to truth so we are
     * currently emitting, whereas IF_FALSE means we are not
     * currently emitting but will start doing so if a %else comes
     * up. In these states, all directives are admissible: %elif,
     * %else and %endif. (And of course %if.)
     */
    COND_IF_TRUE, COND_IF_FALSE,
    /*
     * These states come up after a %else: ELSE_TRUE means we're
     * emitting, and ELSE_FALSE means we're not. In ELSE_* states,
     * any %elif or %else will cause an error.
     */
    COND_ELSE_TRUE, COND_ELSE_FALSE,
    /*
     * This state means that we're not emitting now, and also that
     * nothing until %endif will be emitted at all. It's for use in
     * two circumstances: (i) when we've had our moment of emission
     * and have now started seeing %elifs, and (ii) when the
     * condition construct in question is contained within a
     * non-emitting branch of a larger condition construct.
     */
    COND_NEVER
};
#define emitting(x) ( (x) == COND_IF_TRUE || (x) == COND_ELSE_TRUE )

/*
 * Condition codes. Note that we use c_ prefix not C_ because C_ is
 * used in nasm.h for the "real" condition codes. At _this_ level,
 * we treat CXZ and ECXZ as condition codes, albeit non-invertible
 * ones, so we need a different enum...
 */
static char *conditions[] = {
    "a", "ae", "b", "be", "c", "cxz", "e", "ecxz", "g", "ge", "l", "le",
    "na", "nae", "nb", "nbe", "nc", "ne", "ng", "nge", "nl", "nle", "no",
    "np", "ns", "nz", "o", "p", "pe", "po", "s", "z"
};
enum
{
    c_A, c_AE, c_B, c_BE, c_C, c_CXZ, c_E, c_ECXZ, c_G, c_GE, c_L, c_LE,
    c_NA, c_NAE, c_NB, c_NBE, c_NC, c_NE, c_NG, c_NGE, c_NL, c_NLE, c_NO,
    c_NP, c_NS, c_NZ, c_O, c_P, c_PE, c_PO, c_S, c_Z
};
static int inverse_ccs[] = {
    c_NA, c_NAE, c_NB, c_NBE, c_NC, -1, c_NE, -1, c_NG, c_NGE, c_NL, c_NLE,
    c_A, c_AE, c_B, c_BE, c_C, c_E, c_G, c_GE, c_L, c_LE, c_O, c_P, c_S,
    c_Z, c_NO, c_NP, c_PO, c_PE, c_NS, c_NZ
};

/*
 * Directive names.
 */
static char *directives[] = {
    "%arg",
    "%assign", "%clear", "%define", "%elif", "%elifctx", "%elifdef",
    "%elifid", "%elifidn", "%elifidni", "%elifnctx", "%elifndef",
    "%elifnid", "%elifnidn", "%elifnidni", "%elifnnum", "%elifnstr",
    "%elifnum", "%elifstr", "%else", "%endif", "%endm", "%endmacro",
    "%endrep", "%error", "%exitrep", "%iassign", "%idefine", "%if",
    "%ifctx", "%ifdef", "%ifid", "%ifidn", "%ifidni", "%ifnctx",
    "%ifndef", "%ifnid", "%ifnidn", "%ifnidni", "%ifnnum",
    "%ifnstr", "%ifnum", "%ifstr", "%imacro", "%include",
    "%ixdefine", "%line",
    "%local",
    "%macro", "%pop", "%push", "%rep", "%repl", "%rotate",
    "%stacksize",
    "%strlen", "%substr", "%undef", "%xdefine"
};
enum
{
    PP_ARG,
    PP_ASSIGN, PP_CLEAR, PP_DEFINE, PP_ELIF, PP_ELIFCTX, PP_ELIFDEF,
    PP_ELIFID, PP_ELIFIDN, PP_ELIFIDNI, PP_ELIFNCTX, PP_ELIFNDEF,
    PP_ELIFNID, PP_ELIFNIDN, PP_ELIFNIDNI, PP_ELIFNNUM, PP_ELIFNSTR,
    PP_ELIFNUM, PP_ELIFSTR, PP_ELSE, PP_ENDIF, PP_ENDM, PP_ENDMACRO,
    PP_ENDREP, PP_ERROR, PP_EXITREP, PP_IASSIGN, PP_IDEFINE, PP_IF,
    PP_IFCTX, PP_IFDEF, PP_IFID, PP_IFIDN, PP_IFIDNI, PP_IFNCTX,
    PP_IFNDEF, PP_IFNID, PP_IFNIDN, PP_IFNIDNI, PP_IFNNUM,
    PP_IFNSTR, PP_IFNUM, PP_IFSTR, PP_IMACRO, PP_INCLUDE,
    PP_IXDEFINE, PP_LINE,
    PP_LOCAL,
    PP_MACRO, PP_POP, PP_PUSH, PP_REP, PP_REPL, PP_ROTATE,
    PP_STACKSIZE,
    PP_STRLEN, PP_SUBSTR, PP_UNDEF, PP_XDEFINE
};


/* For TASM compatibility we need to be able to recognise TASM compatible
 * conditional compilation directives. Using the NASM pre-processor does
 * not work, so we look for them specifically from the following list and
 * then jam in the equivalent NASM directive into the input stream.
 */

#ifndef MAX
#       define MAX(a,b) ( ((a) > (b)) ? (a) : (b))
#endif

enum
{
    TM_ARG, TM_ELIF, TM_ELSE, TM_ENDIF, TM_IF, TM_IFDEF, TM_IFDIFI,
    TM_IFNDEF, TM_INCLUDE, TM_LOCAL
};

static char *tasm_directives[] = {
    "arg", "elif", "else", "endif", "if", "ifdef", "ifdifi",
    "ifndef", "include", "local"
};

static int StackSize = 4;
static char *StackPointer = "ebp";
static int ArgOffset = 8;
static int LocalOffset = 4;


static Context *cstk;
static Include *istk;
static IncPath *ipath = NULL;

static efunc __error;           /* Pointer to client-provided error reporting function */
static evalfunc evaluate;

static int pass;                /* HACK: pass 0 = generate dependencies only */

static unsigned long unique;    /* unique identifier numbers */

static Line *predef = NULL;

static ListGen *list;

/*
 * The number of hash values we use for the macro lookup tables.
 * FIXME: We should *really* be able to configure this at run time,
 * or even have the hash table automatically expanding when necessary.
 */
#define NHASH 31

/*
 * The current set of multi-line macros we have defined.
 */
static MMacro *mmacros[NHASH];

/*
 * The current set of single-line macros we have defined.
 */
static SMacro *smacros[NHASH];

/*
 * The multi-line macro we are currently defining, or the %rep
 * block we are currently reading, if any.
 */
static MMacro *defining;

/*
 * The number of macro parameters to allocate space for at a time.
 */
#define PARAM_DELTA 16

/*
 * The standard macro set: defined as `static char *stdmac[]'. Also
 * gives our position in the macro set, when we're processing it.
 */
#include "macros.c"
static char **stdmacpos;

/*
 * The extra standard macros that come from the object format, if
 * any.
 */
static char **extrastdmac = NULL;
int any_extrastdmac;

/*
 * Tokens are allocated in blocks to improve speed
 */
#define TOKEN_BLOCKSIZE 4096
static Token *freeTokens = NULL;
struct Blocks {
        Blocks *next;
        void *chunk;
};

static Blocks blocks = { NULL, NULL };

/*
 * Forward declarations.
 */
static Token *expand_mmac_params(Token * tline);
static Token *expand_smacro(Token * tline);
static Token *expand_id(Token * tline);
static Context *get_ctx(char *name, int all_contexts);
static void make_tok_num(Token * tok, long val);
static void error(int severity, char *fmt, ...);
static void *new_Block(size_t size);
static void delete_Blocks(void);
static Token *new_Token(Token * next, int type, char *text, int txtlen);
static Token *delete_Token(Token * t);

/*
 * Macros for safe checking of token pointers, avoid *(NULL)
 */
#define tok_type_(x,t) ((x) && (x)->type == (t))
#define skip_white_(x) if (tok_type_((x), TOK_WHITESPACE)) (x)=(x)->next
#define tok_is_(x,v) (tok_type_((x), TOK_OTHER) && !strcmp((x)->text,(v)))
#define tok_isnt_(x,v) ((x) && ((x)->type!=TOK_OTHER || strcmp((x)->text,(v))))

/* Handle TASM specific directives, which do not contain a % in
 * front of them. We do it here because I could not find any other
 * place to do it for the moment, and it is a hack (ideally it would
 * be nice to be able to use the NASM pre-processor to do it).
 */
static char *
check_tasm_directive(char *line)
{
    int i, j, k, m, len;
    char *p = line, *oldline, oldchar;

    /* Skip whitespace */
    while (isspace(*p) && *p != 0)
        p++;

    /* Binary search for the directive name */
    i = -1;
    j = sizeof(tasm_directives) / sizeof(*tasm_directives);
    len = 0;
    while (!isspace(p[len]) && p[len] != 0)
        len++;
    if (len)
    {
        oldchar = p[len];
        p[len] = 0;
        while (j - i > 1)
        {
            k = (j + i) / 2;
            m = nasm_stricmp(p, tasm_directives[k]);
            if (m == 0)
            {
                /* We have found a directive, so jam a % in front of it
                 * so that NASM will then recognise it as one if it's own.
                 */
                p[len] = oldchar;
                len = strlen(p);
                oldline = line;
                line = nasm_malloc(len + 2);
                line[0] = '%';
                if (k == TM_IFDIFI)
                {
                    /* NASM does not recognise IFDIFI, so we convert it to
                     * %ifdef BOGUS. This is not used in NASM comaptible
                     * code, but does need to parse for the TASM macro
                     * package.
                     */
                    strcpy(line + 1, "ifdef BOGUS");
                }
                else
                {
                    memcpy(line + 1, p, len + 1);
                }
                nasm_free(oldline);
                return line;
            }
            else if (m < 0)
            {
                j = k;
            }
            else
                i = k;
        }
        p[len] = oldchar;
    }
    return line;
}

/*
 * The pre-preprocessing stage... This function translates line
 * number indications as they emerge from GNU cpp (`# lineno "file"
 * flags') into NASM preprocessor line number indications (`%line
 * lineno file').
 */
static char *
prepreproc(char *line)
{
    int lineno, fnlen;
    char *fname, *oldline;

    if (line[0] == '#' && line[1] == ' ')
    {
        oldline = line;
        fname = oldline + 2;
        lineno = atoi(fname);
        fname += strspn(fname, "0123456789 ");
        if (*fname == '"')
            fname++;
        fnlen = strcspn(fname, "\"");
        line = nasm_malloc(20 + fnlen);
        sprintf(line, "%%line %d %.*s", lineno, fnlen, fname);
        nasm_free(oldline);
    }
    if (tasm_compatible_mode)
        return check_tasm_directive(line);
    return line;
}

/*
 * The hash function for macro lookups. Note that due to some
 * macros having case-insensitive names, the hash function must be
 * invariant under case changes. We implement this by applying a
 * perfectly normal hash function to the uppercase of the string.
 */
static int
hash(char *s)
{
    unsigned int h = 0;
    int i = 0;
    /*
     * Powers of three, mod 31.
     */
    static const int multipliers[] = {
        1, 3, 9, 27, 19, 26, 16, 17, 20, 29, 25, 13, 8, 24, 10,
        30, 28, 22, 4, 12, 5, 15, 14, 11, 2, 6, 18, 23, 7, 21
    };


    while (*s)
    {
        h += multipliers[i] * (unsigned char) (toupper(*s));
        s++;
        if (++i >= sizeof(multipliers) / sizeof(*multipliers))
            i = 0;
    }
    h %= NHASH;
    return h;
}

/*
 * Free a linked list of tokens.
 */
static void
free_tlist(Token * list)
{
    while (list)
    {
        list = delete_Token(list);
    }
}

/*
 * Free a linked list of lines.
 */
static void
free_llist(Line * list)
{
    Line *l;
    while (list)
    {
        l = list;
        list = list->next;
        free_tlist(l->first);
        nasm_free(l);
    }
}

/*
 * Free an MMacro
 */
static void
free_mmacro(MMacro * m)
{
    nasm_free(m->name);
    free_tlist(m->dlist);
    nasm_free(m->defaults);
    free_llist(m->expansion);
    nasm_free(m);
}

/*
 * Pop the context stack.
 */
static void
ctx_pop(void)
{
    Context *c = cstk;
    SMacro *smac, *s;

    cstk = cstk->next;
    smac = c->localmac;
    while (smac)
    {
        s = smac;
        smac = smac->next;
        nasm_free(s->name);
        free_tlist(s->expansion);
        nasm_free(s);
    }
    nasm_free(c->name);
    nasm_free(c);
}

#define BUF_DELTA 512
/*
 * Read a line from the top file in istk, handling multiple CR/LFs
 * at the end of the line read, and handling spurious ^Zs. Will
 * return lines from the standard macro set if this has not already
 * been done.
 */
static char *
read_line(void)
{
    char *buffer, *p, *q;
    int bufsize, continued_count;

    if (stdmacpos)
    {
        if (*stdmacpos)
        {
            char *ret = nasm_strdup(*stdmacpos++);
            if (!*stdmacpos && any_extrastdmac)
            {
                stdmacpos = extrastdmac;
                any_extrastdmac = FALSE;
                return ret;
            }
            /*
             * Nasty hack: here we push the contents of `predef' on
             * to the top-level expansion stack, since this is the
             * most convenient way to implement the pre-include and
             * pre-define features.
             */
            if (!*stdmacpos)
            {
                Line *pd, *l;
                Token *head, **tail, *t;

                for (pd = predef; pd; pd = pd->next)
                {
                    head = NULL;
                    tail = &head;
                    for (t = pd->first; t; t = t->next)
                    {
                        *tail = new_Token(NULL, t->type, t->text, 0);
                        tail = &(*tail)->next;
                    }
                    l = nasm_malloc(sizeof(Line));
                    l->next = istk->expansion;
                    l->first = head;
                    l->finishes = FALSE;
                    istk->expansion = l;
                }
            }
            return ret;
        }
        else
        {
            stdmacpos = NULL;
        }
    }

    bufsize = BUF_DELTA;
    buffer = nasm_malloc(BUF_DELTA);
    p = buffer;
    continued_count = 0;
    while (1)
    {
        q = fgets(p, bufsize - (p - buffer), istk->fp);
        if (!q)
            break;
        p += strlen(p);
        if (p > buffer && p[-1] == '\n')
        {
           /* Convert backslash-CRLF line continuation sequences into
              nothing at all (for DOS and Windows) */
           if (((p - 2) > buffer) && (p[-3] == '\\') && (p[-2] == '\r')) {
               p -= 3;
               *p = 0;
               continued_count++;
           }
           /* Also convert backslash-LF line continuation sequences into
              nothing at all (for Unix) */
           else if (((p - 1) > buffer) && (p[-2] == '\\')) {
               p -= 2;
               *p = 0;
               continued_count++;
           }
           else {
               break;
           }
        }
        if (p - buffer > bufsize - 10)
        {
            long offset = p - buffer;
            bufsize += BUF_DELTA;
            buffer = nasm_realloc(buffer, bufsize);
            p = buffer + offset;        /* prevent stale-pointer problems */
        }
    }

    if (!q && p == buffer)
    {
        nasm_free(buffer);
        return NULL;
    }

    src_set_linnum(src_get_linnum() + istk->lineinc + continued_count);

    /*
     * Play safe: remove CRs as well as LFs, if any of either are
     * present at the end of the line.
     */
    while (--p >= buffer && (*p == '\n' || *p == '\r'))
        *p = '\0';

    /*
     * Handle spurious ^Z, which may be inserted into source files
     * by some file transfer utilities.
     */
    buffer[strcspn(buffer, "\032")] = '\0';

    list->line(LIST_READ, buffer);

    return buffer;
}

/*
 * Tokenise a line of text. This is a very simple process since we
 * don't need to parse the value out of e.g. numeric tokens: we
 * simply split one string into many.
 */
static Token *
tokenise(char *line)
{
    char *p = line;
    int type;
    Token *list = NULL;
    Token *t, **tail = &list;

    while (*line)
    {
        p = line;
        if (*p == '%')
        {
                p++;
                if ( isdigit(*p) ||
                        ((*p == '-' || *p == '+') && isdigit(p[1])) ||
                        ((*p == '+') && (isspace(p[1]) || !p[1])))
                                {
                        do
                        {
                        p++;
                        }
                        while (isdigit(*p));
                        type = TOK_PREPROC_ID;
                }
                else if (*p == '{')
                {
                        p++;
                        while (*p && *p != '}')
                        {
                        p[-1] = *p;
                        p++;
                        }
                        p[-1] = '\0';
                        if (*p)
                        p++;
                        type = TOK_PREPROC_ID;
                }
                else if (isidchar(*p) ||
                                ((*p == '!' || *p == '%' || *p == '$') &&
                                        isidchar(p[1])))
                {
                        do
                        {
                        p++;
                        }
                        while (isidchar(*p));
                        type = TOK_PREPROC_ID;
                }
                else
                {
                        type = TOK_OTHER;
                        if (*p == '%')
                                p++;
                }
        }
        else if (isidstart(*p) || (*p == '$' && isidstart(p[1])))
        {
            type = TOK_ID;
            p++;
            while (*p && isidchar(*p))
                p++;
        }
        else if (*p == '\'' || *p == '"')
        {
            /*
             * A string token.
             */
            char c = *p;
            p++;
            type = TOK_STRING;
            while (*p && *p != c)
                p++;
            if (*p)
            {
                p++;
            }
            else
            {
                error(ERR_WARNING, "unterminated string");
            }
        }
        else if (isnumstart(*p))
        {
            /*
             * A number token.
             */
            type = TOK_NUMBER;
            p++;
            while (*p && isnumchar(*p))
                p++;
        }
        else if (isspace(*p))
        {
            type = TOK_WHITESPACE;
            p++;
            while (*p && isspace(*p))
                p++;
            /*
             * Whitespace just before end-of-line is discarded by
             * pretending it's a comment; whitespace just before a
             * comment gets lumped into the comment.
             */
            if (!*p || *p == ';')
            {
                type = TOK_COMMENT;
                while (*p)
                    p++;
            }
        }
        else if (*p == ';')
        {
            type = TOK_COMMENT;
            while (*p)
                p++;
        }
        else
        {
            /*
             * Anything else is an operator of some kind. We check
             * for all the double-character operators (>>, <<, //,
             * %%, <=, >=, ==, !=, <>, &&, ||, ^^), but anything
             * else is a single-character operator.
             */
            type = TOK_OTHER;
            if ((p[0] == '>' && p[1] == '>') ||
                    (p[0] == '<' && p[1] == '<') ||
                    (p[0] == '/' && p[1] == '/') ||
                    (p[0] == '<' && p[1] == '=') ||
                    (p[0] == '>' && p[1] == '=') ||
                    (p[0] == '=' && p[1] == '=') ||
                    (p[0] == '!' && p[1] == '=') ||
                    (p[0] == '<' && p[1] == '>') ||
                    (p[0] == '&' && p[1] == '&') ||
                    (p[0] == '|' && p[1] == '|') ||
                    (p[0] == '^' && p[1] == '^'))
            {
                p++;
            }
            p++;
        }
        if (type != TOK_COMMENT)
        {
            *tail = t = new_Token(NULL, type, line, p - line);
            tail = &t->next;
        }
        line = p;
    }
    return list;
}

/*
 * this function allocates a new managed block of memory and
 * returns a pointer to the block.  The managed blocks are 
 * deleted only all at once by the delete_Blocks function.
 */
static void *
new_Block(size_t size)
{
        Blocks *b = &blocks;
        
        /* first, get to the end of the linked list      */
        while (b->next)
                b = b->next;
        /* now allocate the requested chunk */
        b->chunk = nasm_malloc(size);
        
        /* now allocate a new block for the next request */
        b->next = nasm_malloc(sizeof(Blocks));
        /* and initialize the contents of the new block */
        b->next->next = NULL;
        b->next->chunk = NULL;
        return b->chunk;
}

/*
 * this function deletes all managed blocks of memory
 */
static void
delete_Blocks(void)
{
        Blocks *a,*b = &blocks;

        /* 
         * keep in mind that the first block, pointed to by blocks
         * is a static and not dynamically allocated, so we don't 
         * free it.
         */
        while (b)
        {
                if (b->chunk)
                        nasm_free(b->chunk);
                a = b;
                b = b->next;
                if (a != &blocks)
                        nasm_free(a);
        }
}       

/*
 *  this function creates a new Token and passes a pointer to it 
 *  back to the caller.  It sets the type and text elements, and
 *  also the mac and next elements to NULL.
 */
static Token *
new_Token(Token * next, int type, char *text, int txtlen)
{
    Token *t;
    int i;

    if (freeTokens == NULL)
    {
        freeTokens = (Token *)new_Block(TOKEN_BLOCKSIZE * sizeof(Token));
        for (i = 0; i < TOKEN_BLOCKSIZE - 1; i++)
            freeTokens[i].next = &freeTokens[i + 1];
        freeTokens[i].next = NULL;
    }
    t = freeTokens;
    freeTokens = t->next;
    t->next = next;
    t->mac = NULL;
    t->type = type;
    if (type == TOK_WHITESPACE || text == NULL)
    {
        t->text = NULL;
    }
    else
    {
        if (txtlen == 0)
            txtlen = strlen(text);
        t->text = nasm_malloc(1 + txtlen);
        strncpy(t->text, text, txtlen);
        t->text[txtlen] = '\0';
    }
    return t;
}

static Token *
delete_Token(Token * t)
{
    Token *next = t->next;
    nasm_free(t->text);
    t->next = freeTokens;
    freeTokens = t;
    return next;
}

/*
 * Convert a line of tokens back into text.
 * If expand_locals is not zero, identifiers of the form "%$*xxx"
 * will be transformed into ..@ctxnum.xxx
 */
static char *
detoken(Token * tlist, int expand_locals)
{
    Token *t;
    int len;
    char *line, *p;

    len = 0;
    for (t = tlist; t; t = t->next)
    {
        if (t->type == TOK_PREPROC_ID && t->text[1] == '!')
        {
            char *p = getenv(t->text + 2);
            nasm_free(t->text);
            if (p)
                t->text = nasm_strdup(p);
            else
                t->text = NULL;
        }
        /* Expand local macros here and not during preprocessing */
        if (expand_locals &&
                t->type == TOK_PREPROC_ID && t->text &&
                t->text[0] == '%' && t->text[1] == '$')
        {
            Context *ctx = get_ctx(t->text, FALSE);
            if (ctx)
            {
                char buffer[40];
                char *p, *q = t->text + 2;

                q += strspn(q, "$");
                sprintf(buffer, "..@%lu.", ctx->number);
                p = nasm_strcat(buffer, q);
                nasm_free(t->text);
                t->text = p;
            }
        }
        if (t->type == TOK_WHITESPACE)
        {
            len++;
        }
        else if (t->text)
        {
            len += strlen(t->text);
        }
    }
    p = line = nasm_malloc(len + 1);
    for (t = tlist; t; t = t->next)
    {
        if (t->type == TOK_WHITESPACE)
        {
            *p = ' ';
                p++;
                *p = '\0';
        }
        else if (t->text)
        {
            strcpy(p, t->text);
            p += strlen(p);
        }
    }
    *p = '\0';
    return line;
}

/*
 * A scanner, suitable for use by the expression evaluator, which
 * operates on a line of Tokens. Expects a pointer to a pointer to
 * the first token in the line to be passed in as its private_data
 * field.
 */
static int
ppscan(void *private_data, struct tokenval *tokval)
{
    Token **tlineptr = private_data;
    Token *tline;

    do
    {
        tline = *tlineptr;
        *tlineptr = tline ? tline->next : NULL;
    }
    while (tline && (tline->type == TOK_WHITESPACE ||
                    tline->type == TOK_COMMENT));

    if (!tline)
        return tokval->t_type = TOKEN_EOS;

    if (tline->text[0] == '$' && !tline->text[1])
        return tokval->t_type = TOKEN_HERE;
    if (tline->text[0] == '$' && tline->text[1] == '$' && !tline->text[1])
        return tokval->t_type = TOKEN_BASE;

    if (tline->type == TOK_ID)
    {
        tokval->t_charptr = tline->text;
        if (tline->text[0] == '$')
        {
            tokval->t_charptr++;
            return tokval->t_type = TOKEN_ID;
        }

        /*
         * This is the only special case we actually need to worry
         * about in this restricted context.
         */
        if (!nasm_stricmp(tline->text, "seg"))
            return tokval->t_type = TOKEN_SEG;

        return tokval->t_type = TOKEN_ID;
    }

    if (tline->type == TOK_NUMBER)
    {
        int rn_error;

        tokval->t_integer = readnum(tline->text, &rn_error);
        if (rn_error)
            return tokval->t_type = TOKEN_ERRNUM;
        tokval->t_charptr = NULL;
        return tokval->t_type = TOKEN_NUM;
    }

    if (tline->type == TOK_STRING)
    {
        int rn_warn;
        char q, *r;
        int l;

        r = tline->text;
        q = *r++;
        l = strlen(r);

        if (l == 0 || r[l - 1] != q)
            return tokval->t_type = TOKEN_ERRNUM;
        tokval->t_integer = readstrnum(r, l - 1, &rn_warn);
        if (rn_warn)
            error(ERR_WARNING | ERR_PASS1, "character constant too long");
        tokval->t_charptr = NULL;
        return tokval->t_type = TOKEN_NUM;
    }

    if (tline->type == TOK_OTHER)
    {
        if (!strcmp(tline->text, "<<"))
            return tokval->t_type = TOKEN_SHL;
        if (!strcmp(tline->text, ">>"))
            return tokval->t_type = TOKEN_SHR;
        if (!strcmp(tline->text, "//"))
            return tokval->t_type = TOKEN_SDIV;
        if (!strcmp(tline->text, "%%"))
            return tokval->t_type = TOKEN_SMOD;
        if (!strcmp(tline->text, "=="))
            return tokval->t_type = TOKEN_EQ;
        if (!strcmp(tline->text, "<>"))
            return tokval->t_type = TOKEN_NE;
        if (!strcmp(tline->text, "!="))
            return tokval->t_type = TOKEN_NE;
        if (!strcmp(tline->text, "<="))
            return tokval->t_type = TOKEN_LE;
        if (!strcmp(tline->text, ">="))
            return tokval->t_type = TOKEN_GE;
        if (!strcmp(tline->text, "&&"))
            return tokval->t_type = TOKEN_DBL_AND;
        if (!strcmp(tline->text, "^^"))
            return tokval->t_type = TOKEN_DBL_XOR;
        if (!strcmp(tline->text, "||"))
            return tokval->t_type = TOKEN_DBL_OR;
    }

    /*
     * We have no other options: just return the first character of
     * the token text.
     */
    return tokval->t_type = tline->text[0];
}

/*
 * Compare a string to the name of an existing macro; this is a
 * simple wrapper which calls either strcmp or nasm_stricmp
 * depending on the value of the `casesense' parameter.
 */
static int
mstrcmp(char *p, char *q, int casesense)
{
    return casesense ? strcmp(p, q) : nasm_stricmp(p, q);
}

/*
 * Return the Context structure associated with a %$ token. Return
 * NULL, having _already_ reported an error condition, if the
 * context stack isn't deep enough for the supplied number of $
 * signs.
 * If all_contexts == TRUE, contexts that enclose current are
 * also scanned for such smacro, until it is found; if not -
 * only the context that directly results from the number of $'s
 * in variable's name.
 */
static Context *
get_ctx(char *name, int all_contexts)
{
    Context *ctx;
    SMacro *m;
    int i;

    if (!name || name[0] != '%' || name[1] != '$')
        return NULL;

    if (!cstk)
    {
        error(ERR_NONFATAL, "`%s': context stack is empty", name);
        return NULL;
    }

    for (i = strspn(name + 2, "$"), ctx = cstk; (i > 0) && ctx; i--)
    {
        ctx = ctx->next;
/*        i--;  Lino - 02/25/02 */
    }
    if (!ctx)
    {
        error(ERR_NONFATAL, "`%s': context stack is only"
                " %d level%s deep", name, i - 1, (i == 2 ? "" : "s"));
        return NULL;
    }
    if (!all_contexts)
        return ctx;

    do
    {
        /* Search for this smacro in found context */
        m = ctx->localmac;
        while (m)
        {
            if (!mstrcmp(m->name, name, m->casesense))
                return ctx;
            m = m->next;
        }
        ctx = ctx->next;
    }
    while (ctx);
    return NULL;
}

/* Add a slash to the end of a path if it is missing. We use the
 * forward slash to make it compatible with Unix systems.
 */
static void
backslash(char *s)
{
    int pos = strlen(s);
    if (s[pos - 1] != '\\' && s[pos - 1] != '/')
    {
        s[pos] = '/';
        s[pos + 1] = '\0';
    }
}

/*
 * Open an include file. This routine must always return a valid
 * file pointer if it returns - it's responsible for throwing an
 * ERR_FATAL and bombing out completely if not. It should also try
 * the include path one by one until it finds the file or reaches
 * the end of the path.
 */
static FILE *
inc_fopen(char *file)
{
    FILE *fp;
    char *prefix = "", *combine;
    IncPath *ip = ipath;
    static int namelen = 0;
    int len = strlen(file);

    while (1)
    {
        combine = nasm_malloc(strlen(prefix) + 1 + len + 1);
        strcpy(combine, prefix);
        if (prefix[0] != 0)
            backslash(combine);
        strcat(combine, file);
        fp = fopen(combine, "r");
        if (pass == 0 && fp)
        {
            namelen += strlen(combine) + 1;
            if (namelen > 62)
            {
                printf(" \\\n  ");
                namelen = 2;
            }
            printf(" %s", combine);
        }
        nasm_free(combine);
        if (fp)
            return fp;
        if (!ip)
            break;
        prefix = ip->path;
        ip = ip->next;
    }

    error(ERR_FATAL, "unable to open include file `%s'", file);
    return NULL;                /* never reached - placate compilers */
}

/*
 * Determine if we should warn on defining a single-line macro of
 * name `name', with `nparam' parameters. If nparam is 0 or -1, will
 * return TRUE if _any_ single-line macro of that name is defined.
 * Otherwise, will return TRUE if a single-line macro with either
 * `nparam' or no parameters is defined.
 *
 * If a macro with precisely the right number of parameters is
 * defined, or nparam is -1, the address of the definition structure
 * will be returned in `defn'; otherwise NULL will be returned. If `defn'
 * is NULL, no action will be taken regarding its contents, and no
 * error will occur.
 *
 * Note that this is also called with nparam zero to resolve
 * `ifdef'.
 *
 * If you already know which context macro belongs to, you can pass
 * the context pointer as first parameter; if you won't but name begins
 * with %$ the context will be automatically computed. If all_contexts
 * is true, macro will be searched in outer contexts as well.
 */
static int
smacro_defined(Context * ctx, char *name, int nparam, SMacro ** defn,
        int nocase)
{
    SMacro *m;

    if (ctx)
        m = ctx->localmac;
    else if (name[0] == '%' && name[1] == '$')
    {
        if (cstk)
            ctx = get_ctx(name, FALSE);
        if (!ctx)
            return FALSE;       /* got to return _something_ */
        m = ctx->localmac;
    }
    else
        m = smacros[hash(name)];

    while (m)
    {
        if (!mstrcmp(m->name, name, m->casesense && nocase) &&
                (nparam <= 0 || m->nparam == 0 || nparam == m->nparam))
        {
            if (defn)
            {
                if (nparam == m->nparam || nparam == -1)
                    *defn = m;
                else
                    *defn = NULL;
            }
            return TRUE;
        }
        m = m->next;
    }

    return FALSE;
}

/*
 * Count and mark off the parameters in a multi-line macro call.
 * This is called both from within the multi-line macro expansion
 * code, and also to mark off the default parameters when provided
 * in a %macro definition line.
 */
static void
count_mmac_params(Token * t, int *nparam, Token *** params)
{
    int paramsize, brace;

    *nparam = paramsize = 0;
    *params = NULL;
    while (t)
    {
        if (*nparam >= paramsize)
        {
            paramsize += PARAM_DELTA;
            *params = nasm_realloc(*params, sizeof(**params) * paramsize);
        }
        skip_white_(t);
        brace = FALSE;
        if (tok_is_(t, "{"))
            brace = TRUE;
        (*params)[(*nparam)++] = t;
        while (tok_isnt_(t, brace ? "}" : ","))
            t = t->next;
        if (t)
        {                       /* got a comma/brace */
            t = t->next;
            if (brace)
            {
                /*
                 * Now we've found the closing brace, look further
                 * for the comma.
                 */
                skip_white_(t);
                if (tok_isnt_(t, ","))
                {
                    error(ERR_NONFATAL,
                            "braces do not enclose all of macro parameter");
                    while (tok_isnt_(t, ","))
                        t = t->next;
                }
                if (t)
                    t = t->next;        /* eat the comma */
            }
        }
    }
}

/*
 * Determine whether one of the various `if' conditions is true or
 * not.
 *
 * We must free the tline we get passed.
 */
static int
if_condition(Token * tline, int i)
{
    int j, casesense;
    Token *t, *tt, **tptr, *origline;
    struct tokenval tokval;
    expr *evalresult;

    origline = tline;

    switch (i)
    {
        case PP_IFCTX:
        case PP_ELIFCTX:
        case PP_IFNCTX:
        case PP_ELIFNCTX:
            j = FALSE;          /* have we matched yet? */
            while (cstk && tline)
            {
                skip_white_(tline);
                if (!tline || tline->type != TOK_ID)
                {
                    error(ERR_NONFATAL,
                            "`%s' expects context identifiers",
                            directives[i]);
                    free_tlist(origline);
                    return -1;
                }
                if (!nasm_stricmp(tline->text, cstk->name))
                    j = TRUE;
                tline = tline->next;
            }
            if (i == PP_IFNCTX || i == PP_ELIFNCTX)
                j = !j;
            free_tlist(origline);
            return j;

        case PP_IFDEF:
        case PP_ELIFDEF:
        case PP_IFNDEF:
        case PP_ELIFNDEF:
            j = FALSE;          /* have we matched yet? */
            while (tline)
            {
                skip_white_(tline);
                if (!tline || (tline->type != TOK_ID &&
                                (tline->type != TOK_PREPROC_ID ||
                                        tline->text[1] != '$')))
                {
                    error(ERR_NONFATAL,
                            "`%%if%sdef' expects macro identifiers",
                            (i == PP_ELIFNDEF ? "n" : ""));
                    free_tlist(origline);
                    return -1;
                }
                if (smacro_defined(NULL, tline->text, 0, NULL, 1))
                    j = TRUE;
                tline = tline->next;
            }
            if (i == PP_IFNDEF || i == PP_ELIFNDEF)
                j = !j;
            free_tlist(origline);
            return j;

        case PP_IFIDN:
        case PP_ELIFIDN:
        case PP_IFNIDN:
        case PP_ELIFNIDN:
        case PP_IFIDNI:
        case PP_ELIFIDNI:
        case PP_IFNIDNI:
        case PP_ELIFNIDNI:
            tline = expand_smacro(tline);
            t = tt = tline;
            while (tok_isnt_(tt, ","))
                tt = tt->next;
            if (!tt)
            {
                error(ERR_NONFATAL,
                        "`%s' expects two comma-separated arguments",
                        directives[i]);
                free_tlist(tline);
                return -1;
            }
            tt = tt->next;
            casesense = (i == PP_IFIDN || i == PP_ELIFIDN ||
                    i == PP_IFNIDN || i == PP_ELIFNIDN);
            j = TRUE;           /* assume equality unless proved not */
            while ((t->type != TOK_OTHER || strcmp(t->text, ",")) && tt)
            {
                if (tt->type == TOK_OTHER && !strcmp(tt->text, ","))
                {
                    error(ERR_NONFATAL, "`%s': more than one comma on line",
                            directives[i]);
                    free_tlist(tline);
                    return -1;
                }
                if (t->type == TOK_WHITESPACE)
                {
                    t = t->next;
                    continue;
                }
                else if (tt->type == TOK_WHITESPACE)
                {
                    tt = tt->next;
                    continue;
                }
                else if (tt->type != t->type ||
                        mstrcmp(tt->text, t->text, casesense))
                {
                    j = FALSE;  /* found mismatching tokens */
                    break;
                }
                else
                {
                    t = t->next;
                    tt = tt->next;
                    continue;
                }
            }
            if ((t->type != TOK_OTHER || strcmp(t->text, ",")) || tt)
                j = FALSE;      /* trailing gunk on one end or other */
            if (i == PP_IFNIDN || i == PP_ELIFNIDN ||
                    i == PP_IFNIDNI || i == PP_ELIFNIDNI)
                j = !j;
            free_tlist(tline);
            return j;

        case PP_IFID:
        case PP_ELIFID:
        case PP_IFNID:
        case PP_ELIFNID:
        case PP_IFNUM:
        case PP_ELIFNUM:
        case PP_IFNNUM:
        case PP_ELIFNNUM:
        case PP_IFSTR:
        case PP_ELIFSTR:
        case PP_IFNSTR:
        case PP_ELIFNSTR:
            tline = expand_smacro(tline);
            t = tline;
            while (tok_type_(t, TOK_WHITESPACE))
                t = t->next;
            j = FALSE;          /* placate optimiser */
            if (t)
                switch (i)
                {
                    case PP_IFID:
                    case PP_ELIFID:
                    case PP_IFNID:
                    case PP_ELIFNID:
                        j = (t->type == TOK_ID);
                        break;
                    case PP_IFNUM:
                    case PP_ELIFNUM:
                    case PP_IFNNUM:
                    case PP_ELIFNNUM:
                        j = (t->type == TOK_NUMBER);
                        break;
                    case PP_IFSTR:
                    case PP_ELIFSTR:
                    case PP_IFNSTR:
                    case PP_ELIFNSTR:
                        j = (t->type == TOK_STRING);
                        break;
                }
            if (i == PP_IFNID || i == PP_ELIFNID ||
                    i == PP_IFNNUM || i == PP_ELIFNNUM ||
                    i == PP_IFNSTR || i == PP_ELIFNSTR)
                j = !j;
            free_tlist(tline);
            return j;

        case PP_IF:
        case PP_ELIF:
            t = tline = expand_smacro(tline);
            tptr = &t;
            tokval.t_type = TOKEN_INVALID;
            evalresult = evaluate(ppscan, tptr, &tokval,
                    NULL, pass | CRITICAL, error, NULL);
            free_tlist(tline);
            if (!evalresult)
                return -1;
            if (tokval.t_type)
                error(ERR_WARNING,
                        "trailing garbage after expression ignored");
            if (!is_simple(evalresult))
            {
                error(ERR_NONFATAL,
                        "non-constant value given to `%s'", directives[i]);
                return -1;
            }
            return reloc_value(evalresult) != 0;

        default:
            error(ERR_FATAL,
                    "preprocessor directive `%s' not yet implemented",
                    directives[i]);
            free_tlist(origline);
            return -1;          /* yeah, right */
    }
}

/*
 * Expand macros in a string. Used in %error and %include directives.
 * First tokenise the string, apply "expand_smacro" and then de-tokenise back.
 * The returned variable should ALWAYS be freed after usage.
 */
void
expand_macros_in_string(char **p)
{
    Token *line = tokenise(*p);
    line = expand_smacro(line);
    *p = detoken(line, FALSE);
}

/*
 * Find out if a line contains a preprocessor directive, and deal
 * with it if so.
 * 
 * If a directive _is_ found, we are expected to free_tlist() the
 * line.
 *
 * Return values go like this:
 * 
 * bit 0 is set if a directive was found (so the line gets freed)
 */
static int
do_directive(Token * tline)
{
    int i, j, k, m, nparam, nolist;
    int offset;
    char *p, *mname;
    Include *inc;
    Context *ctx;
    Cond *cond;
    SMacro *smac, **smhead;
    MMacro *mmac;
    Token *t, *tt, *param_start, *macro_start, *last, **tptr, *origline;
    Line *l;
    struct tokenval tokval;
    expr *evalresult;
    MMacro *tmp_defining;       /* Used when manipulating rep_nest */

    origline = tline;

    skip_white_(tline);
    if (!tok_type_(tline, TOK_PREPROC_ID) ||
            (tline->text[1] == '%' || tline->text[1] == '$'
                    || tline->text[1] == '!'))
        return 0;

    i = -1;
    j = sizeof(directives) / sizeof(*directives);
    while (j - i > 1)
    {
        k = (j + i) / 2;
        m = nasm_stricmp(tline->text, directives[k]);
        if (m == 0) {
                if (tasm_compatible_mode) {
                i = k;
                j = -2;
                } else if (k != PP_ARG && k != PP_LOCAL && k != PP_STACKSIZE) {
                    i = k;
                j = -2;
                }
            break;
        }
        else if (m < 0) {
            j = k;
        }
        else
            i = k;
    }

    /*
     * If we're in a non-emitting branch of a condition construct,
     * or walking to the end of an already terminated %rep block,
     * we should ignore all directives except for condition
     * directives.
     */
    if (((istk->conds && !emitting(istk->conds->state)) ||
                    (istk->mstk && !istk->mstk->in_progress)) &&
            i != PP_IF && i != PP_ELIF &&
            i != PP_IFCTX && i != PP_ELIFCTX &&
            i != PP_IFDEF && i != PP_ELIFDEF &&
            i != PP_IFID && i != PP_ELIFID &&
            i != PP_IFIDN && i != PP_ELIFIDN &&
            i != PP_IFIDNI && i != PP_ELIFIDNI &&
            i != PP_IFNCTX && i != PP_ELIFNCTX &&
            i != PP_IFNDEF && i != PP_ELIFNDEF &&
            i != PP_IFNID && i != PP_ELIFNID &&
            i != PP_IFNIDN && i != PP_ELIFNIDN &&
            i != PP_IFNIDNI && i != PP_ELIFNIDNI &&
            i != PP_IFNNUM && i != PP_ELIFNNUM &&
            i != PP_IFNSTR && i != PP_ELIFNSTR &&
            i != PP_IFNUM && i != PP_ELIFNUM &&
            i != PP_IFSTR && i != PP_ELIFSTR && i != PP_ELSE && i != PP_ENDIF)
    {
        return 0;
    }

    /*
     * If we're defining a macro or reading a %rep block, we should
     * ignore all directives except for %macro/%imacro (which
     * generate an error), %endm/%endmacro, and (only if we're in a
     * %rep block) %endrep. If we're in a %rep block, another %rep
     * causes an error, so should be let through.
     */
    if (defining && i != PP_MACRO && i != PP_IMACRO &&
            i != PP_ENDMACRO && i != PP_ENDM &&
            (defining->name || (i != PP_ENDREP && i != PP_REP)))
    {
        return 0;
    }

    if (j != -2)
    {
        error(ERR_NONFATAL, "unknown preprocessor directive `%s'",
                tline->text);
        return 0;               /* didn't get it */
    }

    switch (i)
    {
        case PP_STACKSIZE:
            /* Directive to tell NASM what the default stack size is. The
             * default is for a 16-bit stack, and this can be overriden with
             * %stacksize large.
             * the following form:
             *
             *      ARG arg1:WORD, arg2:DWORD, arg4:QWORD
             */
            tline = tline->next;
            if (tline && tline->type == TOK_WHITESPACE)
                tline = tline->next;
            if (!tline || tline->type != TOK_ID)
            {
                error(ERR_NONFATAL, "`%%stacksize' missing size parameter");
                free_tlist(origline);
                return 3;
            }
            if (nasm_stricmp(tline->text, "flat") == 0)
            {
                /* All subsequent ARG directives are for a 32-bit stack */
                StackSize = 4;
                StackPointer = "ebp";
                ArgOffset = 8;
                LocalOffset = 4;
            }
            else if (nasm_stricmp(tline->text, "large") == 0)
            {
                /* All subsequent ARG directives are for a 16-bit stack,
                 * far function call.
                 */
                StackSize = 2;
                StackPointer = "bp";
                ArgOffset = 4;
                LocalOffset = 2;
            }
            else if (nasm_stricmp(tline->text, "small") == 0)
            {
                /* All subsequent ARG directives are for a 16-bit stack,
                   * far function call. We don't support near functions.
                 */
                StackSize = 2;
                StackPointer = "bp";
                ArgOffset = 6;
                LocalOffset = 2;
            }
            else
            {
                error(ERR_NONFATAL, "`%%stacksize' invalid size type");
                free_tlist(origline);
                return 3;
            }
            free_tlist(origline);
            return 3;

        case PP_ARG:
            /* TASM like ARG directive to define arguments to functions, in
             * the following form:
             *
             *      ARG arg1:WORD, arg2:DWORD, arg4:QWORD
             */
            offset = ArgOffset;
            do
            {
                char *arg, directive[256];
                int size = StackSize;

                /* Find the argument name */
                tline = tline->next;
                if (tline && tline->type == TOK_WHITESPACE)
                    tline = tline->next;
                if (!tline || tline->type != TOK_ID)
                {
                    error(ERR_NONFATAL, "`%%arg' missing argument parameter");
                    free_tlist(origline);
                    return 3;
                }
                arg = tline->text;

                /* Find the argument size type */
                tline = tline->next;
                if (!tline || tline->type != TOK_OTHER
                        || tline->text[0] != ':')
                {
                    error(ERR_NONFATAL,
                            "Syntax error processing `%%arg' directive");
                    free_tlist(origline);
                    return 3;
                }
                tline = tline->next;
                if (!tline || tline->type != TOK_ID)
                {
                    error(ERR_NONFATAL,
                            "`%%arg' missing size type parameter");
                    free_tlist(origline);
                    return 3;
                }

                /* Allow macro expansion of type parameter */
                tt = tokenise(tline->text);
                tt = expand_smacro(tt);
                if (nasm_stricmp(tt->text, "byte") == 0)
                {
                    size = MAX(StackSize, 1);
                }
                else if (nasm_stricmp(tt->text, "word") == 0)
                {
                    size = MAX(StackSize, 2);
                }
                else if (nasm_stricmp(tt->text, "dword") == 0)
                {
                    size = MAX(StackSize, 4);
                }
                else if (nasm_stricmp(tt->text, "qword") == 0)
                {
                    size = MAX(StackSize, 8);
                }
                else if (nasm_stricmp(tt->text, "tword") == 0)
                {
                    size = MAX(StackSize, 10);
                }
                else
                {
                    error(ERR_NONFATAL,
                            "Invalid size type for `%%arg' missing directive");
                    free_tlist(tt);
                    free_tlist(origline);
                    return 3;
                }
                free_tlist(tt);

                /* Now define the macro for the argument */
                sprintf(directive, "%%define %s (%s+%d)", arg, StackPointer,
                        offset);
                do_directive(tokenise(directive));
                offset += size;

                /* Move to the next argument in the list */
                tline = tline->next;
                if (tline && tline->type == TOK_WHITESPACE)
                    tline = tline->next;
            }
            while (tline && tline->type == TOK_OTHER
                    && tline->text[0] == ',');
            free_tlist(origline);
            return 3;

        case PP_LOCAL:
            /* TASM like LOCAL directive to define local variables for a
             * function, in the following form:
             *
             *      LOCAL local1:WORD, local2:DWORD, local4:QWORD = LocalSize
             *
             * The '= LocalSize' at the end is ignored by NASM, but is
             * required by TASM to define the local parameter size (and used
             * by the TASM macro package).
             */
            offset = LocalOffset;
            do
            {
                char *local, directive[256];
                int size = StackSize;

                /* Find the argument name */
                tline = tline->next;
                if (tline && tline->type == TOK_WHITESPACE)
                    tline = tline->next;
                if (!tline || tline->type != TOK_ID)
                {
                    error(ERR_NONFATAL,
                            "`%%local' missing argument parameter");
                    free_tlist(origline);
                    return 3;
                }
                local = tline->text;

                /* Find the argument size type */
                tline = tline->next;
                if (!tline || tline->type != TOK_OTHER
                        || tline->text[0] != ':')
                {
                    error(ERR_NONFATAL,
                            "Syntax error processing `%%local' directive");
                    free_tlist(origline);
                    return 3;
                }
                tline = tline->next;
                if (!tline || tline->type != TOK_ID)
                {
                    error(ERR_NONFATAL,
                            "`%%local' missing size type parameter");
                    free_tlist(origline);
                    return 3;
                }

                /* Allow macro expansion of type parameter */
                tt = tokenise(tline->text);
                tt = expand_smacro(tt);
                if (nasm_stricmp(tt->text, "byte") == 0)
                {
                    size = MAX(StackSize, 1);
                }
                else if (nasm_stricmp(tt->text, "word") == 0)
                {
                    size = MAX(StackSize, 2);
                }
                else if (nasm_stricmp(tt->text, "dword") == 0)
                {
                    size = MAX(StackSize, 4);
                }
                else if (nasm_stricmp(tt->text, "qword") == 0)
                {
                    size = MAX(StackSize, 8);
                }
                else if (nasm_stricmp(tt->text, "tword") == 0)
                {
                    size = MAX(StackSize, 10);
                }
                else
                {
                    error(ERR_NONFATAL,
                            "Invalid size type for `%%local' missing directive");
                    free_tlist(tt);
                    free_tlist(origline);
                    return 3;
                }
                free_tlist(tt);

                /* Now define the macro for the argument */
                sprintf(directive, "%%define %s (%s-%d)", local, StackPointer,
                        offset);
                do_directive(tokenise(directive));
                offset += size;

                /* Now define the assign to setup the enter_c macro correctly */
                sprintf(directive, "%%assign %%$localsize %%$localsize+%d",
                        size);
                do_directive(tokenise(directive));

                /* Move to the next argument in the list */
                tline = tline->next;
                if (tline && tline->type == TOK_WHITESPACE)
                    tline = tline->next;
            }
            while (tline && tline->type == TOK_OTHER
                    && tline->text[0] == ',');
            free_tlist(origline);
            return 3;

        case PP_CLEAR:
            if (tline->next)
                error(ERR_WARNING,
                        "trailing garbage after `%%clear' ignored");
            for (j = 0; j < NHASH; j++)
            {
                while (mmacros[j])
                {
                    MMacro *m = mmacros[j];
                    mmacros[j] = m->next;
                    free_mmacro(m);
                }
                while (smacros[j])
                {
                    SMacro *s = smacros[j];
                    smacros[j] = smacros[j]->next;
                    nasm_free(s->name);
                    free_tlist(s->expansion);
                    nasm_free(s);
                }
            }
            free_tlist(origline);
            return 3;

        case PP_INCLUDE:
            tline = tline->next;
            skip_white_(tline);
            if (!tline || (tline->type != TOK_STRING &&
                            tline->type != TOK_INTERNAL_STRING))
            {
                error(ERR_NONFATAL, "`%%include' expects a file name");
                free_tlist(origline);
                return 3;       /* but we did _something_ */
            }
            if (tline->next)
                error(ERR_WARNING,
                        "trailing garbage after `%%include' ignored");
            if (tline->type != TOK_INTERNAL_STRING)
            {
                p = tline->text + 1;    /* point past the quote to the name */
                p[strlen(p) - 1] = '\0';        /* remove the trailing quote */
            }
            else
                p = tline->text;        /* internal_string is easier */
            expand_macros_in_string(&p);
            inc = nasm_malloc(sizeof(Include));
            inc->next = istk;
            inc->conds = NULL;
            inc->fp = inc_fopen(p);
            inc->fname = src_set_fname(p);
            inc->lineno = src_set_linnum(0);
            inc->lineinc = 1;
            inc->expansion = NULL;
            inc->mstk = NULL;
            istk = inc;
            list->uplevel(LIST_INCLUDE);
            free_tlist(origline);
            return 5;

        case PP_PUSH:
            tline = tline->next;
            skip_white_(tline);
            tline = expand_id(tline);
            if (!tok_type_(tline, TOK_ID))
            {
                error(ERR_NONFATAL, "`%%push' expects a context identifier");
                free_tlist(origline);
                return 3;       /* but we did _something_ */
            }
            if (tline->next)
                error(ERR_WARNING, "trailing garbage after `%%push' ignored");
            ctx = nasm_malloc(sizeof(Context));
            ctx->next = cstk;
            ctx->localmac = NULL;
            ctx->name = nasm_strdup(tline->text);
            ctx->number = unique++;
            cstk = ctx;
            free_tlist(origline);
            break;

        case PP_REPL:
            tline = tline->next;
            skip_white_(tline);
            tline = expand_id(tline);
            if (!tok_type_(tline, TOK_ID))
            {
                error(ERR_NONFATAL, "`%%repl' expects a context identifier");
                free_tlist(origline);
                return 3;       /* but we did _something_ */
            }
            if (tline->next)
                error(ERR_WARNING, "trailing garbage after `%%repl' ignored");
            if (!cstk)
                error(ERR_NONFATAL, "`%%repl': context stack is empty");
            else
            {
                nasm_free(cstk->name);
                cstk->name = nasm_strdup(tline->text);
            }
            free_tlist(origline);
            break;

        case PP_POP:
            if (tline->next)
                error(ERR_WARNING, "trailing garbage after `%%pop' ignored");
            if (!cstk)
                error(ERR_NONFATAL,
                        "`%%pop': context stack is already empty");
            else
                ctx_pop();
            free_tlist(origline);
            break;

        case PP_ERROR:
            tline->next = expand_smacro(tline->next);
            tline = tline->next;
            skip_white_(tline);
            if (tok_type_(tline, TOK_STRING))
            {
                p = tline->text + 1;    /* point past the quote to the name */
                p[strlen(p) - 1] = '\0';        /* remove the trailing quote */
                expand_macros_in_string(&p);
                error(ERR_NONFATAL, "%s", p);
                nasm_free(p);
            }
            else
            {
                p = detoken(tline, FALSE);
                error(ERR_WARNING, "%s", p);
                nasm_free(p);
            }
            free_tlist(origline);
            break;

        case PP_IF:
        case PP_IFCTX:
        case PP_IFDEF:
        case PP_IFID:
        case PP_IFIDN:
        case PP_IFIDNI:
        case PP_IFNCTX:
        case PP_IFNDEF:
        case PP_IFNID:
        case PP_IFNIDN:
        case PP_IFNIDNI:
        case PP_IFNNUM:
        case PP_IFNSTR:
        case PP_IFNUM:
        case PP_IFSTR:
            if (istk->conds && !emitting(istk->conds->state))
                j = COND_NEVER;
            else
            {
                j = if_condition(tline->next, i);
                tline->next = NULL;     /* it got freed */
                free_tlist(origline);
                j = j < 0 ? COND_NEVER : j ? COND_IF_TRUE : COND_IF_FALSE;
            }
            cond = nasm_malloc(sizeof(Cond));
            cond->next = istk->conds;
            cond->state = j;
            istk->conds = cond;
            return (j == COND_IF_TRUE ? 3 : 1);

        case PP_ELIF:
        case PP_ELIFCTX:
        case PP_ELIFDEF:
        case PP_ELIFID:
        case PP_ELIFIDN:
        case PP_ELIFIDNI:
        case PP_ELIFNCTX:
        case PP_ELIFNDEF:
        case PP_ELIFNID:
        case PP_ELIFNIDN:
        case PP_ELIFNIDNI:
        case PP_ELIFNNUM:
        case PP_ELIFNSTR:
        case PP_ELIFNUM:
        case PP_ELIFSTR:
            if (!istk->conds)
                error(ERR_FATAL, "`%s': no matching `%%if'", directives[i]);
            if (emitting(istk->conds->state)
                    || istk->conds->state == COND_NEVER)
                istk->conds->state = COND_NEVER;
            else
            {
                j = if_condition(expand_mmac_params(tline->next), i);
                tline->next = NULL;     /* it got freed */
                free_tlist(origline);
                istk->conds->state =
                        j < 0 ? COND_NEVER : j ? COND_IF_TRUE : COND_IF_FALSE;
            }
            return (istk->conds->state == COND_IF_TRUE ? 5 : 1);

        case PP_ELSE:
            if (tline->next)
                error(ERR_WARNING, "trailing garbage after `%%else' ignored");
            if (!istk->conds)
                error(ERR_FATAL, "`%%else': no matching `%%if'");
            if (emitting(istk->conds->state)
                    || istk->conds->state == COND_NEVER)
                istk->conds->state = COND_ELSE_FALSE;
            else
                istk->conds->state = COND_ELSE_TRUE;
            free_tlist(origline);
            return 5;

        case PP_ENDIF:
            if (tline->next)
                error(ERR_WARNING,
                        "trailing garbage after `%%endif' ignored");
            if (!istk->conds)
                error(ERR_FATAL, "`%%endif': no matching `%%if'");
            cond = istk->conds;
            istk->conds = cond->next;
            nasm_free(cond);
            free_tlist(origline);
            return 5;

        case PP_MACRO:
        case PP_IMACRO:
            if (defining)
                error(ERR_FATAL,
                        "`%%%smacro': already defining a macro",
                        (i == PP_IMACRO ? "i" : ""));
            tline = tline->next;
            skip_white_(tline);
            tline = expand_id(tline);
            if (!tok_type_(tline, TOK_ID))
            {
                error(ERR_NONFATAL,
                        "`%%%smacro' expects a macro name",
                        (i == PP_IMACRO ? "i" : ""));
                return 3;
            }
            defining = nasm_malloc(sizeof(MMacro));
            defining->name = nasm_strdup(tline->text);
            defining->casesense = (i == PP_MACRO);
            defining->plus = FALSE;
            defining->nolist = FALSE;
            defining->in_progress = FALSE;
            defining->rep_nest = NULL;
            tline = expand_smacro(tline->next);
            skip_white_(tline);
            if (!tok_type_(tline, TOK_NUMBER))
            {
                error(ERR_NONFATAL,
                        "`%%%smacro' expects a parameter count",
                        (i == PP_IMACRO ? "i" : ""));
                defining->nparam_min = defining->nparam_max = 0;
            }
            else
            {
                defining->nparam_min = defining->nparam_max =
                        readnum(tline->text, &j);
                if (j)
                    error(ERR_NONFATAL,
                            "unable to parse parameter count `%s'",
                            tline->text);
            }
            if (tline && tok_is_(tline->next, "-"))
            {
                tline = tline->next->next;
                if (tok_is_(tline, "*"))
                    defining->nparam_max = INT_MAX;
                else if (!tok_type_(tline, TOK_NUMBER))
                    error(ERR_NONFATAL,
                            "`%%%smacro' expects a parameter count after `-'",
                            (i == PP_IMACRO ? "i" : ""));
                else
                {
                    defining->nparam_max = readnum(tline->text, &j);
                    if (j)
                        error(ERR_NONFATAL,
                                "unable to parse parameter count `%s'",
                                tline->text);
                    if (defining->nparam_min > defining->nparam_max)
                        error(ERR_NONFATAL,
                                "minimum parameter count exceeds maximum");
                }
            }
            if (tline && tok_is_(tline->next, "+"))
            {
                tline = tline->next;
                defining->plus = TRUE;
            }
            if (tline && tok_type_(tline->next, TOK_ID) &&
                    !nasm_stricmp(tline->next->text, ".nolist"))
            {
                tline = tline->next;
                defining->nolist = TRUE;
            }
            mmac = mmacros[hash(defining->name)];
            while (mmac)
            {
                if (!strcmp(mmac->name, defining->name) &&
                        (mmac->nparam_min <= defining->nparam_max
                                || defining->plus)
                        && (defining->nparam_min <= mmac->nparam_max
                                || mmac->plus))
                {
                    error(ERR_WARNING,
                            "redefining multi-line macro `%s'",
                            defining->name);
                    break;
                }
                mmac = mmac->next;
            }
            /*
             * Handle default parameters.
             */
            if (tline && tline->next)
            {
                defining->dlist = tline->next;
                tline->next = NULL;
                count_mmac_params(defining->dlist, &defining->ndefs,
                        &defining->defaults);
            }
            else
            {
                defining->dlist = NULL;
                defining->defaults = NULL;
            }
            defining->expansion = NULL;
            free_tlist(origline);
            return 1;

        case PP_ENDM:
        case PP_ENDMACRO:
            if (!defining)
            {
                error(ERR_NONFATAL, "`%s': not defining a macro",
                        tline->text);
                return 3;
            }
            k = hash(defining->name);
            defining->next = mmacros[k];
            mmacros[k] = defining;
            defining = NULL;
            free_tlist(origline);
            return 5;

        case PP_ROTATE:
            if (tline->next && tline->next->type == TOK_WHITESPACE)
                tline = tline->next;
            t = expand_smacro(tline->next);
            tline->next = NULL;
            free_tlist(origline);
            tline = t;
            tptr = &t;
            tokval.t_type = TOKEN_INVALID;
            evalresult =
                    evaluate(ppscan, tptr, &tokval, NULL, pass, error, NULL);
            free_tlist(tline);
            if (!evalresult)
                return 3;
            if (tokval.t_type)
                error(ERR_WARNING,
                        "trailing garbage after expression ignored");
            if (!is_simple(evalresult))
            {
                error(ERR_NONFATAL, "non-constant value given to `%%rotate'");
                return 3;
            }
            mmac = istk->mstk;
            while (mmac && !mmac->name) /* avoid mistaking %reps for macros */
                mmac = mmac->next_active;
            if (!mmac)
                error(ERR_NONFATAL,
                        "`%%rotate' invoked outside a macro call");
            mmac->rotate = mmac->rotate + reloc_value(evalresult);
            if (mmac->rotate < 0)
                mmac->rotate = mmac->nparam - (-mmac->rotate) % mmac->nparam;
            mmac->rotate %= mmac->nparam;
            return 1;

        case PP_REP:
            nolist = FALSE;
            tline = tline->next;
            if (tline->next && tline->next->type == TOK_WHITESPACE)
                tline = tline->next;
            if (tline->next && tline->next->type == TOK_ID &&
                    !nasm_stricmp(tline->next->text, ".nolist"))
            {
                tline = tline->next;
                nolist = TRUE;
            }
            t = expand_smacro(tline->next);
            tline->next = NULL;
            free_tlist(origline);
            tline = t;
            tptr = &t;
            tokval.t_type = TOKEN_INVALID;
            evalresult =
                    evaluate(ppscan, tptr, &tokval, NULL, pass, error, NULL);
            free_tlist(tline);
            if (!evalresult)
                return 3;
            if (tokval.t_type)
                error(ERR_WARNING,
                        "trailing garbage after expression ignored");
            if (!is_simple(evalresult))
            {
                error(ERR_NONFATAL, "non-constant value given to `%%rep'");
                return 3;
            }
            tmp_defining = defining;
            defining = nasm_malloc(sizeof(MMacro));
            defining->name = NULL;      /* flags this macro as a %rep block */
            defining->casesense = 0;
            defining->plus = FALSE;
            defining->nolist = nolist;
            defining->in_progress = reloc_value(evalresult) + 1;
            defining->nparam_min = defining->nparam_max = 0;
            defining->defaults = NULL;
            defining->dlist = NULL;
            defining->expansion = NULL;
            defining->next_active = istk->mstk;
            defining->rep_nest = tmp_defining;
            return 1;

        case PP_ENDREP:
            if (!defining || defining->name)
            {
                error(ERR_NONFATAL, "`%%endrep': no matching `%%rep'");
                return 3;
            }

            /*
             * Now we have a "macro" defined - although it has no name
             * and we won't be entering it in the hash tables - we must
             * push a macro-end marker for it on to istk->expansion.
             * After that, it will take care of propagating itself (a
             * macro-end marker line for a macro which is really a %rep
             * block will cause the macro to be re-expanded, complete
             * with another macro-end marker to ensure the process
             * continues) until the whole expansion is forcibly removed
             * from istk->expansion by a %exitrep.
             */
            l = nasm_malloc(sizeof(Line));
            l->next = istk->expansion;
            l->finishes = defining;
            l->first = NULL;
            istk->expansion = l;

            istk->mstk = defining;

            list->uplevel(defining->nolist ? LIST_MACRO_NOLIST : LIST_MACRO);
            tmp_defining = defining;
            defining = defining->rep_nest;
            free_tlist(origline);
            return 1;

        case PP_EXITREP:
            /*
             * We must search along istk->expansion until we hit a
             * macro-end marker for a macro with no name. Then we set
             * its `in_progress' flag to 0.
             */
            for (l = istk->expansion; l; l = l->next)
                if (l->finishes && !l->finishes->name)
                    break;

            if (l)
                l->finishes->in_progress = 0;
            else
                error(ERR_NONFATAL, "`%%exitrep' not within `%%rep' block");
            free_tlist(origline);
            return 1;

        case PP_XDEFINE:
        case PP_IXDEFINE:
        case PP_DEFINE:
        case PP_IDEFINE:
            tline = tline->next;
            skip_white_(tline);
            tline = expand_id(tline);
            if (!tline || (tline->type != TOK_ID &&
                            (tline->type != TOK_PREPROC_ID ||
                                    tline->text[1] != '$')))
            {
                error(ERR_NONFATAL,
                        "`%%%s%sdefine' expects a macro identifier",
                        ((i == PP_IDEFINE || i == PP_IXDEFINE) ? "i" : ""),
                        ((i == PP_XDEFINE || i == PP_IXDEFINE) ? "x" : ""));
                free_tlist(origline);
                return 3;
            }

            ctx = get_ctx(tline->text, FALSE);
            if (!ctx)
                smhead = &smacros[hash(tline->text)];
            else
                smhead = &ctx->localmac;
            mname = tline->text;
            last = tline;
            param_start = tline = tline->next;
            nparam = 0;

            /* Expand the macro definition now for %xdefine and %ixdefine */
            if ((i == PP_XDEFINE) || (i == PP_IXDEFINE))
                tline = expand_smacro(tline);

            if (tok_is_(tline, "("))
            {
                /*
                 * This macro has parameters.
                 */

                tline = tline->next;
                while (1)
                {
                    skip_white_(tline);
                    if (!tline)
                    {
                        error(ERR_NONFATAL, "parameter identifier expected");
                        free_tlist(origline);
                        return 3;
                    }
                    if (tline->type != TOK_ID)
                    {
                        error(ERR_NONFATAL,
                                "`%s': parameter identifier expected",
                                tline->text);
                        free_tlist(origline);
                        return 3;
                    }
                    tline->type = TOK_SMAC_PARAM + nparam++;
                    tline = tline->next;
                    skip_white_(tline);
                    if (tok_is_(tline, ","))
                    {
                        tline = tline->next;
                        continue;
                    }
                    if (!tok_is_(tline, ")"))
                    {
                        error(ERR_NONFATAL,
                                "`)' expected to terminate macro template");
                        free_tlist(origline);
                        return 3;
                    }
                    break;
                }
                last = tline;
                tline = tline->next;
            }
            if (tok_type_(tline, TOK_WHITESPACE))
                last = tline, tline = tline->next;
            macro_start = NULL;
            last->next = NULL;
            t = tline;
            while (t)
            {
                if (t->type == TOK_ID)
                {
                    for (tt = param_start; tt; tt = tt->next)
                        if (tt->type >= TOK_SMAC_PARAM &&
                                !strcmp(tt->text, t->text))
                            t->type = tt->type;
                }
                tt = t->next;
                t->next = macro_start;
                macro_start = t;
                t = tt;
            }
            /*
             * Good. We now have a macro name, a parameter count, and a
             * token list (in reverse order) for an expansion. We ought
             * to be OK just to create an SMacro, store it, and let
             * free_tlist have the rest of the line (which we have
             * carefully re-terminated after chopping off the expansion
             * from the end).
             */
            if (smacro_defined(ctx, mname, nparam, &smac, i == PP_DEFINE))
            {
                if (!smac)
                {
                    error(ERR_WARNING,
                            "single-line macro `%s' defined both with and"
                            " without parameters", mname);
                    free_tlist(origline);
                    free_tlist(macro_start);
                    return 3;
                }
                else
                {
                    /*
                     * We're redefining, so we have to take over an
                     * existing SMacro structure. This means freeing
                     * what was already in it.
                     */
                    nasm_free(smac->name);
                    free_tlist(smac->expansion);
                }
            }
            else
            {
                smac = nasm_malloc(sizeof(SMacro));
                smac->next = *smhead;
                *smhead = smac;
            }
            smac->name = nasm_strdup(mname);
            smac->casesense = ((i == PP_DEFINE) || (i == PP_XDEFINE));
            smac->nparam = nparam;
            smac->expansion = macro_start;
            smac->in_progress = FALSE;
            free_tlist(origline);
            return 3;

        case PP_UNDEF:
            tline = tline->next;
            skip_white_(tline);
            tline = expand_id(tline);
            if (!tline || (tline->type != TOK_ID &&
                            (tline->type != TOK_PREPROC_ID ||
                                    tline->text[1] != '$')))
            {
                error(ERR_NONFATAL, "`%%undef' expects a macro identifier");
                free_tlist(origline);
                return 3;
            }
            if (tline->next)
            {
                error(ERR_WARNING,
                        "trailing garbage after macro name ignored");
            }

            /* Find the context that symbol belongs to */
            ctx = get_ctx(tline->text, FALSE);
            if (!ctx)
                smhead = &smacros[hash(tline->text)];
            else
                smhead = &ctx->localmac;

            mname = tline->text;
            last = tline;
            last->next = NULL;

            /*
             * We now have a macro name... go hunt for it.
             */
            while (smacro_defined(ctx, mname, -1, &smac, 1))
            {
                /* Defined, so we need to find its predecessor and nuke it */
                SMacro **s;
                for (s = smhead; *s && *s != smac; s = &(*s)->next);
                if (*s)
                {
                    *s = smac->next;
                    nasm_free(smac->name);
                    free_tlist(smac->expansion);
                    nasm_free(smac);
                }
            }
            free_tlist(origline);
            return 3;

        case PP_STRLEN:
            tline = tline->next;
            skip_white_(tline);
            tline = expand_id(tline);
            if (!tline || (tline->type != TOK_ID &&
                            (tline->type != TOK_PREPROC_ID ||
                                    tline->text[1] != '$')))
            {
                error(ERR_NONFATAL,
                        "`%%strlen' expects a macro identifier as first parameter");
                free_tlist(origline);
                return 3;
            }
            ctx = get_ctx(tline->text, FALSE);
            if (!ctx)
                smhead = &smacros[hash(tline->text)];
            else
                smhead = &ctx->localmac;
            mname = tline->text;
            last = tline;
            tline = expand_smacro(tline->next);
            last->next = NULL;

            t = tline;
            while (tok_type_(t, TOK_WHITESPACE))
                t = t->next;
            /* t should now point to the string */
            if (t->type != TOK_STRING)
            {
                error(ERR_NONFATAL,
                        "`%%strlen` requires string as second parameter");
                free_tlist(tline);
                free_tlist(origline);
                return 3;
            }

            macro_start = nasm_malloc(sizeof(*macro_start));
            macro_start->next = NULL;
            make_tok_num(macro_start, strlen(t->text) - 2);
            macro_start->mac = NULL;

            /*
             * We now have a macro name, an implicit parameter count of
             * zero, and a numeric token to use as an expansion. Create
             * and store an SMacro.
             */
            if (smacro_defined(ctx, mname, 0, &smac, i == PP_STRLEN))
            {
                if (!smac)
                    error(ERR_WARNING,
                            "single-line macro `%s' defined both with and"
                            " without parameters", mname);
                else
                {
                    /*
                     * We're redefining, so we have to take over an
                     * existing SMacro structure. This means freeing
                     * what was already in it.
                     */
                    nasm_free(smac->name);
                    free_tlist(smac->expansion);
                }
            }
            else
            {
                smac = nasm_malloc(sizeof(SMacro));
                smac->next = *smhead;
                *smhead = smac;
            }
            smac->name = nasm_strdup(mname);
            smac->casesense = (i == PP_STRLEN);
            smac->nparam = 0;
            smac->expansion = macro_start;
            smac->in_progress = FALSE;
            free_tlist(tline);
            free_tlist(origline);
            return 3;

        case PP_SUBSTR:
            tline = tline->next;
            skip_white_(tline);
            tline = expand_id(tline);
            if (!tline || (tline->type != TOK_ID &&
                            (tline->type != TOK_PREPROC_ID ||
                                    tline->text[1] != '$')))
            {
                error(ERR_NONFATAL,
                        "`%%substr' expects a macro identifier as first parameter");
                free_tlist(origline);
                return 3;
            }
            ctx = get_ctx(tline->text, FALSE);
            if (!ctx)
                smhead = &smacros[hash(tline->text)];
            else
                smhead = &ctx->localmac;
            mname = tline->text;
            last = tline;
            tline = expand_smacro(tline->next);
            last->next = NULL;

            t = tline->next;
            while (tok_type_(t, TOK_WHITESPACE))
                t = t->next;

            /* t should now point to the string */
            if (t->type != TOK_STRING)
            {
                error(ERR_NONFATAL,
                        "`%%substr` requires string as second parameter");
                free_tlist(tline);
                free_tlist(origline);
                return 3;
            }

            tt = t->next;
            tptr = &tt;
            tokval.t_type = TOKEN_INVALID;
            evalresult =
                    evaluate(ppscan, tptr, &tokval, NULL, pass, error, NULL);
            if (!evalresult)
            {
                free_tlist(tline);
                free_tlist(origline);
                return 3;
            }
            if (!is_simple(evalresult))
            {
                error(ERR_NONFATAL, "non-constant value given to `%%substr`");
                free_tlist(tline);
                free_tlist(origline);
                return 3;
            }

            macro_start = nasm_malloc(sizeof(*macro_start));
            macro_start->next = NULL;
            macro_start->text = nasm_strdup("'''");
            if (evalresult->value > 0
                    && evalresult->value < strlen(t->text) - 1)
            {
                macro_start->text[1] = t->text[evalresult->value];
            }
            else
            {
                macro_start->text[2] = '\0';
            }
            macro_start->type = TOK_STRING;
            macro_start->mac = NULL;

            /*
             * We now have a macro name, an implicit parameter count of
             * zero, and a numeric token to use as an expansion. Create
             * and store an SMacro.
             */
            if (smacro_defined(ctx, mname, 0, &smac, i == PP_SUBSTR))
            {
                if (!smac)
                    error(ERR_WARNING,
                            "single-line macro `%s' defined both with and"
                            " without parameters", mname);
                else
                {
                    /*
                     * We're redefining, so we have to take over an
                     * existing SMacro structure. This means freeing
                     * what was already in it.
                     */
                    nasm_free(smac->name);
                    free_tlist(smac->expansion);
                }
            }
            else
            {
                smac = nasm_malloc(sizeof(SMacro));
                smac->next = *smhead;
                *smhead = smac;
            }
            smac->name = nasm_strdup(mname);
            smac->casesense = (i == PP_SUBSTR);
            smac->nparam = 0;
            smac->expansion = macro_start;
            smac->in_progress = FALSE;
            free_tlist(tline);
            free_tlist(origline);
            return 3;


        case PP_ASSIGN:
        case PP_IASSIGN:
            tline = tline->next;
            skip_white_(tline);
            tline = expand_id(tline);
            if (!tline || (tline->type != TOK_ID &&
                            (tline->type != TOK_PREPROC_ID ||
                                    tline->text[1] != '$')))
            {
                error(ERR_NONFATAL,
                        "`%%%sassign' expects a macro identifier",
                        (i == PP_IASSIGN ? "i" : ""));
                free_tlist(origline);
                return 3;
            }
            ctx = get_ctx(tline->text, FALSE);
            if (!ctx)
                smhead = &smacros[hash(tline->text)];
            else
                smhead = &ctx->localmac;
            mname = tline->text;
            last = tline;
            tline = expand_smacro(tline->next);
            last->next = NULL;

            t = tline;
            tptr = &t;
            tokval.t_type = TOKEN_INVALID;
            evalresult =
                    evaluate(ppscan, tptr, &tokval, NULL, pass, error, NULL);
            free_tlist(tline);
            if (!evalresult)
            {
                free_tlist(origline);
                return 3;
            }

            if (tokval.t_type)
                error(ERR_WARNING,
                        "trailing garbage after expression ignored");

            if (!is_simple(evalresult))
            {
                error(ERR_NONFATAL,
                        "non-constant value given to `%%%sassign'",
                        (i == PP_IASSIGN ? "i" : ""));
                free_tlist(origline);
                return 3;
            }

            macro_start = nasm_malloc(sizeof(*macro_start));
            macro_start->next = NULL;
            make_tok_num(macro_start, reloc_value(evalresult));
            macro_start->mac = NULL;

            /*
             * We now have a macro name, an implicit parameter count of
             * zero, and a numeric token to use as an expansion. Create
             * and store an SMacro.
             */
            if (smacro_defined(ctx, mname, 0, &smac, i == PP_ASSIGN))
            {
                if (!smac)
                    error(ERR_WARNING,
                            "single-line macro `%s' defined both with and"
                            " without parameters", mname);
                else
                {
                    /*
                     * We're redefining, so we have to take over an
                     * existing SMacro structure. This means freeing
                     * what was already in it.
                     */
                    nasm_free(smac->name);
                    free_tlist(smac->expansion);
                }
            }
            else
            {
                smac = nasm_malloc(sizeof(SMacro));
                smac->next = *smhead;
                *smhead = smac;
            }
            smac->name = nasm_strdup(mname);
            smac->casesense = (i == PP_ASSIGN);
            smac->nparam = 0;
            smac->expansion = macro_start;
            smac->in_progress = FALSE;
            free_tlist(origline);
            return 3;

        case PP_LINE:
            /*
             * Syntax is `%line nnn[+mmm] [filename]'
             */
            tline = tline->next;
            skip_white_(tline);
            if (!tok_type_(tline, TOK_NUMBER))
            {
                error(ERR_NONFATAL, "`%%line' expects line number");
                free_tlist(origline);
                return 3;
            }
            k = readnum(tline->text, &j);
            m = 1;
            tline = tline->next;
            if (tok_is_(tline, "+"))
            {
                tline = tline->next;
                if (!tok_type_(tline, TOK_NUMBER))
                {
                    error(ERR_NONFATAL, "`%%line' expects line increment");
                    free_tlist(origline);
                    return 3;
                }
                m = readnum(tline->text, &j);
                tline = tline->next;
            }
            skip_white_(tline);
            src_set_linnum(k);
            istk->lineinc = m;
            if (tline)
            {
                nasm_free(src_set_fname(detoken(tline, FALSE)));
            }
            free_tlist(origline);
            return 5;

        default:
            error(ERR_FATAL,
                    "preprocessor directive `%s' not yet implemented",
                    directives[i]);
            break;
    }
    return 3;
}

/*
 * Ensure that a macro parameter contains a condition code and
 * nothing else. Return the condition code index if so, or -1
 * otherwise.
 */
static int
find_cc(Token * t)
{
    Token *tt;
    int i, j, k, m;

    skip_white_(t);
    if (t->type != TOK_ID)
        return -1;
    tt = t->next;
    skip_white_(tt);
    if (tt && (tt->type != TOK_OTHER || strcmp(tt->text, ",")))
        return -1;

    i = -1;
    j = sizeof(conditions) / sizeof(*conditions);
    while (j - i > 1)
    {
        k = (j + i) / 2;
        m = nasm_stricmp(t->text, conditions[k]);
        if (m == 0)
        {
            i = k;
            j = -2;
            break;
        }
        else if (m < 0)
        {
            j = k;
        }
        else
            i = k;
    }
    if (j != -2)
        return -1;
    return i;
}

/*
 * Expand MMacro-local things: parameter references (%0, %n, %+n,
 * %-n) and MMacro-local identifiers (%%foo).
 */
static Token *
expand_mmac_params(Token * tline)
{
    Token *t, *tt, **tail, *thead;

    tail = &thead;
    thead = NULL;

    while (tline)
    {
        if (tline->type == TOK_PREPROC_ID &&
                (((tline->text[1] == '+' || tline->text[1] == '-')
                                && tline->text[2]) || tline->text[1] == '%'
                        || (tline->text[1] >= '0' && tline->text[1] <= '9')))
        {
            char *text = NULL;
            int type = 0, cc;   /* type = 0 to placate optimisers */
            char tmpbuf[30];
            int n, i;
            MMacro *mac;

            t = tline;
            tline = tline->next;

            mac = istk->mstk;
            while (mac && !mac->name)   /* avoid mistaking %reps for macros */
                mac = mac->next_active;
            if (!mac)
                error(ERR_NONFATAL, "`%s': not in a macro call", t->text);
            else
                switch (t->text[1])
                {
                        /*
                         * We have to make a substitution of one of the
                         * forms %1, %-1, %+1, %%foo, %0.
                         */
                    case '0':
                        type = TOK_NUMBER;
                        sprintf(tmpbuf, "%d", mac->nparam);
                        text = nasm_strdup(tmpbuf);
                        break;
                    case '%':
                        type = TOK_ID;
                        sprintf(tmpbuf, "..@%lu.", mac->unique);
                        text = nasm_strcat(tmpbuf, t->text + 2);
                        break;
                    case '-':
                        n = atoi(t->text + 2) - 1;
                        if (n >= mac->nparam)
                            tt = NULL;
                        else
                        {
                            if (mac->nparam > 1)
                                n = (n + mac->rotate) % mac->nparam;
                            tt = mac->params[n];
                        }
                        cc = find_cc(tt);
                        if (cc == -1)
                        {
                            error(ERR_NONFATAL,
                                    "macro parameter %d is not a condition code",
                                    n + 1);
                            text = NULL;
                        }
                        else
                        {
                            type = TOK_ID;
                            if (inverse_ccs[cc] == -1)
                            {
                                error(ERR_NONFATAL,
                                        "condition code `%s' is not invertible",
                                        conditions[cc]);
                                text = NULL;
                            }
                            else
                                text =
                                        nasm_strdup(conditions[inverse_ccs
                                                 [cc]]);
                        }
                        break;
                    case '+':
                        n = atoi(t->text + 2) - 1;
                        if (n >= mac->nparam)
                            tt = NULL;
                        else
                        {
                            if (mac->nparam > 1)
                                n = (n + mac->rotate) % mac->nparam;
                            tt = mac->params[n];
                        }
                        cc = find_cc(tt);
                        if (cc == -1)
                        {
                            error(ERR_NONFATAL,
                                    "macro parameter %d is not a condition code",
                                    n + 1);
                            text = NULL;
                        }
                        else
                        {
                            type = TOK_ID;
                            text = nasm_strdup(conditions[cc]);
                        }
                        break;
                    default:
                        n = atoi(t->text + 1) - 1;
                        if (n >= mac->nparam)
                            tt = NULL;
                        else
                        {
                            if (mac->nparam > 1)
                                n = (n + mac->rotate) % mac->nparam;
                            tt = mac->params[n];
                        }
                        if (tt)
                        {
                            for (i = 0; i < mac->paramlen[n]; i++)
                            {
                                *tail =
                                        new_Token(NULL, tt->type, tt->text,
                                        0);
                                tail = &(*tail)->next;
                                tt = tt->next;
                            }
                        }
                        text = NULL;    /* we've done it here */
                        break;
                }
            if (!text)
            {
                delete_Token(t);
            }
            else
            {
                *tail = t;
                tail = &t->next;
                t->type = type;
                nasm_free(t->text);
                t->text = text;
                t->mac = NULL;
            }
            continue;
        }
        else
        {
            t = *tail = tline;
            tline = tline->next;
            t->mac = NULL;
            tail = &t->next;
        }
    }
    *tail = NULL;
    t = thead;
    for (; t && (tt = t->next) != NULL; t = t->next)
        switch (t->type)
        {
            case TOK_WHITESPACE:
                if (tt->type == TOK_WHITESPACE)
                {
                    t->next = delete_Token(tt);
                }
                break;
            case TOK_ID:
                if (tt->type == TOK_ID || tt->type == TOK_NUMBER)
                {
                    char *tmp = nasm_strcat(t->text, tt->text);
                    nasm_free(t->text);
                    t->text = tmp;
                    t->next = delete_Token(tt);
                }
                break;
            case TOK_NUMBER:
                if (tt->type == TOK_NUMBER)
                {
                    char *tmp = nasm_strcat(t->text, tt->text);
                    nasm_free(t->text);
                    t->text = tmp;
                    t->next = delete_Token(tt);
                }
                break;
        }

    return thead;
}

/*
 * Expand all single-line macro calls made in the given line.
 * Return the expanded version of the line. The original is deemed
 * to be destroyed in the process. (In reality we'll just move
 * Tokens from input to output a lot of the time, rather than
 * actually bothering to destroy and replicate.)
 */
static Token *
expand_smacro(Token * tline)
{
    Token *t, *tt, *mstart, **tail, *thead;
    SMacro *head = NULL, *m;
    Token **params;
    int *paramsize;
    int nparam, sparam, brackets, rescan;
    Token *org_tline = tline;
    Context *ctx;
    char *mname;

    /*
     * Trick: we should avoid changing the start token pointer since it can
     * be contained in "next" field of other token. Because of this
     * we allocate a copy of first token and work with it; at the end of
     * routine we copy it back
     */
    if (org_tline)
    {
        tline =
                new_Token(org_tline->next, org_tline->type, org_tline->text,
                0);
        tline->mac = org_tline->mac;
        nasm_free(org_tline->text);
        org_tline->text = NULL;
    }

  again:
    tail = &thead;
    thead = NULL;

    while (tline)
    {                           /* main token loop */
        if ((mname = tline->text))
        {
            /* if this token is a local macro, look in local context */
            if (tline->type == TOK_ID || tline->type == TOK_PREPROC_ID)
                ctx = get_ctx(mname, TRUE);
            else
                ctx = NULL;
            if (!ctx)
                head = smacros[hash(mname)];
            else
                head = ctx->localmac;
            /*
             * We've hit an identifier. As in is_mmacro below, we first
             * check whether the identifier is a single-line macro at
             * all, then think about checking for parameters if
             * necessary.
             */
            for (m = head; m; m = m->next)
                if (!mstrcmp(m->name, mname, m->casesense))
                    break;
            if (m)
            {
                mstart = tline;
                params = NULL;
                paramsize = NULL;
                if (m->nparam == 0)
                {
                    /*
                     * Simple case: the macro is parameterless. Discard the
                     * one token that the macro call took, and push the
                     * expansion back on the to-do stack.
                     */
                    if (!m->expansion)
                    {
                        if (!strcmp("__FILE__", m->name))
                        {
                            long num = 0;
                            src_get(&num, &(tline->text));
                            nasm_quote(&(tline->text));
                            tline->type = TOK_STRING;
                            continue;
                        }
                        if (!strcmp("__LINE__", m->name))
                        {
                            nasm_free(tline->text);
                            make_tok_num(tline, src_get_linnum());
                            continue;
                        }
                        tline = delete_Token(tline);
                        continue;
                    }
                }
                else
                {
                    /*
                     * Complicated case: at least one macro with this name
                     * exists and takes parameters. We must find the
                     * parameters in the call, count them, find the SMacro
                     * that corresponds to that form of the macro call, and
                     * substitute for the parameters when we expand. What a
                     * pain.
                     */
                    tline = tline->next;
                    skip_white_(tline);
                    if (!tok_is_(tline, "("))
                    {
                        /*
                         * This macro wasn't called with parameters: ignore
                         * the call. (Behaviour borrowed from gnu cpp.)
                         */
                        tline = mstart;
                        m = NULL;
                    }
                    else
                    {
                        int paren = 0;
                        int white = 0;
                        brackets = 0;
                        nparam = 0;
                        tline = tline->next;
                        sparam = PARAM_DELTA;
                        params = nasm_malloc(sparam * sizeof(Token *));
                        params[0] = tline;
                        paramsize = nasm_malloc(sparam * sizeof(int));
                        paramsize[0] = 0;
                        for (;; tline = tline->next)
                        {       /* parameter loop */
                            if (!tline)
                            {
                                error(ERR_NONFATAL,
                                        "macro call expects terminating `)'");
                                break;
                            }
                            if (tline->type == TOK_WHITESPACE
                                    && brackets <= 0)
                            {
                                if (paramsize[nparam])
                                    white++;
                                else
                                    params[nparam] = tline->next;
                                continue;       /* parameter loop */
                            }
                            if (tline->type == TOK_OTHER
                                    && tline->text[1] == 0)
                            {
                                char ch = tline->text[0];
                                if (ch == ',' && !paren && brackets <= 0)
                                {
                                    if (++nparam >= sparam)
                                    {
                                        sparam += PARAM_DELTA;
                                        params = nasm_realloc(params,
                                                sparam * sizeof(Token *));
                                        paramsize = nasm_realloc(paramsize,
                                                sparam * sizeof(int));
                                    }
                                    params[nparam] = tline->next;
                                    paramsize[nparam] = 0;
                                    white = 0;
                                    continue;   /* parameter loop */
                                }
                                if (ch == '{' &&
                                        (brackets > 0 || (brackets == 0 &&
                                                        !paramsize[nparam])))
                                {
                                    if (!(brackets++))
                                    {
                                        params[nparam] = tline->next;
                                        continue;       /* parameter loop */
                                    }
                                }
                                if (ch == '}' && brackets > 0)
                                    if (--brackets == 0)
                                    {
                                        brackets = -1;
                                        continue;       /* parameter loop */
                                    }
                                if (ch == '(' && !brackets)
                                    paren++;
                                if (ch == ')' && brackets <= 0)
                                    if (--paren < 0)
                                        break;
                            }
                            if (brackets < 0)
                            {
                                brackets = 0;
                                error(ERR_NONFATAL, "braces do not "
                                        "enclose all of macro parameter");
                            }
                            paramsize[nparam] += white + 1;
                            white = 0;
                        }       /* parameter loop */
                        nparam++;
                        while (m && (m->nparam != nparam ||
                                        mstrcmp(m->name, mname,
                                                m->casesense)))
                            m = m->next;
                        if (!m)
                            error(ERR_WARNING | ERR_WARN_MNP,
                                    "macro `%s' exists, "
                                    "but not taking %d parameters",
                                    mstart->text, nparam);
                    }
                }
                if (m && m->in_progress)
                    m = NULL;
                if (!m)         /* in progess or didn't find '(' or wrong nparam */
                {
                    /* 
                     * Design question: should we handle !tline, which
                     * indicates missing ')' here, or expand those
                     * macros anyway, which requires the (t) test a few
                     * lines down?  
                     */
                    nasm_free(params);
                    nasm_free(paramsize);
                    tline = mstart;
                }
                else
                {
                    /*
                     * Expand the macro: we are placed on the last token of the
                     * call, so that we can easily split the call from the
                     * following tokens. We also start by pushing an SMAC_END
                     * token for the cycle removal.
                     */
                    t = tline;
                    if (t)
                    {
                        tline = t->next;
                        t->next = NULL;
                    }
                    tt = new_Token(tline, TOK_SMAC_END, NULL, 0);
                    tt->mac = m;
                    m->in_progress = TRUE;
                    tline = tt;
                    for (t = m->expansion; t; t = t->next)
                    {
                        if (t->type >= TOK_SMAC_PARAM)
                        {
                            Token *pcopy = tline, **ptail = &pcopy;
                            Token *ttt, *pt;
                            int i;

                            ttt = params[t->type - TOK_SMAC_PARAM];
                            for (i = paramsize[t->type - TOK_SMAC_PARAM];
                                    --i >= 0;)
                            {
                                pt = *ptail =
                                        new_Token(tline, ttt->type, ttt->text,
                                        0);
                                ptail = &pt->next;
                                ttt = ttt->next;
                            }
                            tline = pcopy;
                        }
                        else
                        {
                            tt = new_Token(tline, t->type, t->text, 0);
                            tline = tt;
                        }
                    }

                    /*
                     * Having done that, get rid of the macro call, and clean
                     * up the parameters.
                     */
                    nasm_free(params);
                    nasm_free(paramsize);
                    free_tlist(mstart);
                    continue;   /* main token loop */
                }
            }
        }

        if (tline->type == TOK_SMAC_END)
        {
            tline->mac->in_progress = FALSE;
            tline = delete_Token(tline);
        }
        else
        {
            t = *tail = tline;
            tline = tline->next;
            t->mac = NULL;
            t->next = NULL;
            tail = &t->next;
        }
    }

    /*
     * Now scan the entire line and look for successive TOK_IDs that resulted
     * after expansion (they can't be produced by tokenise()). The successive
     * TOK_IDs should be concatenated.
     * Also we look for %+ tokens and concatenate the tokens before and after
     * them (without white spaces in between).
     */
    t = thead;
    rescan = 0;
    while (t)
    {
        while (t && t->type != TOK_ID && t->type != TOK_PREPROC_ID)
            t = t->next;
        if (!t || !t->next)
            break;
        if (t->next->type == TOK_ID ||
                t->next->type == TOK_PREPROC_ID ||
                t->next->type == TOK_NUMBER)
        {
            char *p = nasm_strcat(t->text, t->next->text);
            nasm_free(t->text);
            t->next = delete_Token(t->next);
            t->text = p;
            rescan = 1;
        }
        else if (t->next->type == TOK_WHITESPACE && t->next->next &&
                t->next->next->type == TOK_PREPROC_ID &&
                strcmp(t->next->next->text, "%+") == 0)
        {
            /* free the next whitespace, the %+ token and next whitespace */
            int i;
            for (i = 1; i <= 3; i++)
            {
                if (!t->next || (i != 2 && t->next->type != TOK_WHITESPACE))
                    break;
                t->next = delete_Token(t->next);
            }                   /* endfor */
        }
        else
            t = t->next;
    }
    /* If we concatenaded something, re-scan the line for macros */
    if (rescan)
    {
        tline = thead;
        goto again;
    }

    if (org_tline)
    {
        if (thead)
        {
            *org_tline = *thead;
            /* since we just gave text to org_line, don't free it */
            thead->text = NULL;
            delete_Token(thead);
        }
        else
        {
            /* the expression expanded to empty line;
               we can't return NULL for some reasons
               we just set the line to a single WHITESPACE token. */
            memset(org_tline, 0, sizeof(*org_tline));
            org_tline->text = NULL;
            org_tline->type = TOK_WHITESPACE;
        }
        thead = org_tline;
    }

    return thead;
}

/*
 * Similar to expand_smacro but used exclusively with macro identifiers
 * right before they are fetched in. The reason is that there can be
 * identifiers consisting of several subparts. We consider that if there
 * are more than one element forming the name, user wants a expansion,
 * otherwise it will be left as-is. Example:
 *
 *      %define %$abc cde
 *
 * the identifier %$abc will be left as-is so that the handler for %define
 * will suck it and define the corresponding value. Other case:
 *
 *      %define _%$abc cde
 *
 * In this case user wants name to be expanded *before* %define starts
 * working, so we'll expand %$abc into something (if it has a value;
 * otherwise it will be left as-is) then concatenate all successive
 * PP_IDs into one.
 */
static Token *
expand_id(Token * tline)
{
    Token *cur, *oldnext = NULL;

    if (!tline || !tline->next)
        return tline;

    cur = tline;
    while (cur->next &&
            (cur->next->type == TOK_ID ||
        cur->next->type == TOK_PREPROC_ID || cur->next->type == TOK_NUMBER))
        cur = cur->next;

    /* If identifier consists of just one token, don't expand */
    if (cur == tline)
        return tline;

    if (cur)
    {
        oldnext = cur->next;    /* Detach the tail past identifier */
        cur->next = NULL;       /* so that expand_smacro stops here */
    }

    tline = expand_smacro(tline);

    if (cur)
    {
        /* expand_smacro possibly changhed tline; re-scan for EOL */
        cur = tline;
        while (cur && cur->next)
            cur = cur->next;
        if (cur)
            cur->next = oldnext;
    }

    return tline;
}

/*
 * Determine whether the given line constitutes a multi-line macro
 * call, and return the MMacro structure called if so. Doesn't have
 * to check for an initial label - that's taken care of in
 * expand_mmacro - but must check numbers of parameters. Guaranteed
 * to be called with tline->type == TOK_ID, so the putative macro
 * name is easy to find.
 */
static MMacro *
is_mmacro(Token * tline, Token *** params_array)
{
    MMacro *head, *m;
    Token **params;
    int nparam;

    head = mmacros[hash(tline->text)];

    /*
     * Efficiency: first we see if any macro exists with the given
     * name. If not, we can return NULL immediately. _Then_ we
     * count the parameters, and then we look further along the
     * list if necessary to find the proper MMacro.
     */
    for (m = head; m; m = m->next)
        if (!mstrcmp(m->name, tline->text, m->casesense))
            break;
    if (!m)
        return NULL;

    /*
     * OK, we have a potential macro. Count and demarcate the
     * parameters.
     */
    count_mmac_params(tline->next, &nparam, &params);

    /*
     * So we know how many parameters we've got. Find the MMacro
     * structure that handles this number.
     */
    while (m)
    {
        if (m->nparam_min <= nparam && (m->plus || nparam <= m->nparam_max))
        {
            /*
             * This one is right. Just check if cycle removal
             * prohibits us using it before we actually celebrate...
             */
            if (m->in_progress)
            {
#if 0
                error(ERR_NONFATAL,
                        "self-reference in multi-line macro `%s'", m->name);
#endif
                nasm_free(params);
                return NULL;
            }
            /*
             * It's right, and we can use it. Add its default
             * parameters to the end of our list if necessary.
             */
            if (m->defaults && nparam < m->nparam_min + m->ndefs)
            {
                params =
                        nasm_realloc(params,
                        ((m->nparam_min + m->ndefs + 1) * sizeof(*params)));
                while (nparam < m->nparam_min + m->ndefs)
                {
                    params[nparam] = m->defaults[nparam - m->nparam_min];
                    nparam++;
                }
            }
            /*
             * If we've gone over the maximum parameter count (and
             * we're in Plus mode), ignore parameters beyond
             * nparam_max.
             */
            if (m->plus && nparam > m->nparam_max)
                nparam = m->nparam_max;
            /*
             * Then terminate the parameter list, and leave.
             */
            if (!params)
            {                   /* need this special case */
                params = nasm_malloc(sizeof(*params));
                nparam = 0;
            }
            params[nparam] = NULL;
            *params_array = params;
            return m;
        }
        /*
         * This one wasn't right: look for the next one with the
         * same name.
         */
        for (m = m->next; m; m = m->next)
            if (!mstrcmp(m->name, tline->text, m->casesense))
                break;
    }

    /*
     * After all that, we didn't find one with the right number of
     * parameters. Issue a warning, and fail to expand the macro.
     */
    error(ERR_WARNING | ERR_WARN_MNP,
            "macro `%s' exists, but not taking %d parameters",
            tline->text, nparam);
    nasm_free(params);
    return NULL;
}

/*
 * Expand the multi-line macro call made by the given line, if
 * there is one to be expanded. If there is, push the expansion on
 * istk->expansion and return 1. Otherwise return 0.
 */
static int
expand_mmacro(Token * tline)
{
    Token *startline = tline;
    Token *label = NULL;
    int dont_prepend = 0;
    Token **params, *t, *tt;
    MMacro *m;
    Line *l, *ll;
    int i, nparam, *paramlen;

    t = tline;
    skip_white_(t);
/*    if (!tok_type_(t, TOK_ID))  Lino 02/25/02 */
    if (!tok_type_(t, TOK_ID) && !tok_type_(t, TOK_PREPROC_ID))
        return 0;
    m = is_mmacro(t, &params);
    if (!m)
    {
        Token *last;
        /*
         * We have an id which isn't a macro call. We'll assume
         * it might be a label; we'll also check to see if a
         * colon follows it. Then, if there's another id after
         * that lot, we'll check it again for macro-hood.
         */
        label = last = t;
        t = t->next;
        if (tok_type_(t, TOK_WHITESPACE))
            last = t, t = t->next;
        if (tok_is_(t, ":"))
        {
            dont_prepend = 1;
            last = t, t = t->next;
            if (tok_type_(t, TOK_WHITESPACE))
                last = t, t = t->next;
        }
        if (!tok_type_(t, TOK_ID) || (m = is_mmacro(t, &params)) == NULL)
            return 0;
        last->next = NULL;
        tline = t;
    }

    /*
     * Fix up the parameters: this involves stripping leading and
     * trailing whitespace, then stripping braces if they are
     * present.
     */
    for (nparam = 0; params[nparam]; nparam++)
        ;
    paramlen = nparam ? nasm_malloc(nparam * sizeof(*paramlen)) : NULL;

    for (i = 0; params[i]; i++)
    {
        int brace = FALSE;
        int comma = (!m->plus || i < nparam - 1);

        t = params[i];
        skip_white_(t);
        if (tok_is_(t, "{"))
            t = t->next, brace = TRUE, comma = FALSE;
        params[i] = t;
        paramlen[i] = 0;
        while (t)
        {
            if (comma && t->type == TOK_OTHER && !strcmp(t->text, ","))
                break;          /* ... because we have hit a comma */
            if (comma && t->type == TOK_WHITESPACE && tok_is_(t->next, ","))
                break;          /* ... or a space then a comma */
            if (brace && t->type == TOK_OTHER && !strcmp(t->text, "}"))
                break;          /* ... or a brace */
            t = t->next;
            paramlen[i]++;
        }
    }

    /*
     * OK, we have a MMacro structure together with a set of
     * parameters. We must now go through the expansion and push
     * copies of each Line on to istk->expansion. Substitution of
     * parameter tokens and macro-local tokens doesn't get done
     * until the single-line macro substitution process; this is
     * because delaying them allows us to change the semantics
     * later through %rotate.
     *
     * First, push an end marker on to istk->expansion, mark this
     * macro as in progress, and set up its invocation-specific
     * variables.
     */
    ll = nasm_malloc(sizeof(Line));
    ll->next = istk->expansion;
    ll->finishes = m;
    ll->first = NULL;
    istk->expansion = ll;

    m->in_progress = TRUE;
    m->params = params;
    m->iline = tline;
    m->nparam = nparam;
    m->rotate = 0;
    m->paramlen = paramlen;
    m->unique = unique++;
    m->lineno = 0;

    m->next_active = istk->mstk;
    istk->mstk = m;

    for (l = m->expansion; l; l = l->next)
    {
        Token **tail;

        ll = nasm_malloc(sizeof(Line));
        ll->finishes = NULL;
        ll->next = istk->expansion;
        istk->expansion = ll;
        tail = &ll->first;

        for (t = l->first; t; t = t->next)
        {
            Token *x = t;
            if (t->type == TOK_PREPROC_ID &&
                    t->text[1] == '0' && t->text[2] == '0')
            {
                dont_prepend = -1;
                x = label;
                if (!x)
                    continue;
            }
            tt = *tail = new_Token(NULL, x->type, x->text, 0);
            tail = &tt->next;
        }
        *tail = NULL;
    }

    /*
     * If we had a label, push it on as the first line of
     * the macro expansion.
     */
    if (label)
    {
        if (dont_prepend < 0)
            free_tlist(startline);
        else
        {
            ll = nasm_malloc(sizeof(Line));
            ll->finishes = NULL;
            ll->next = istk->expansion;
            istk->expansion = ll;
            ll->first = startline;
            if (!dont_prepend)
            {
                while (label->next)
                    label = label->next;
                label->next = tt = new_Token(NULL, TOK_OTHER, ":", 0);
            }
        }
    }

    list->uplevel(m->nolist ? LIST_MACRO_NOLIST : LIST_MACRO);

    return 1;
}

/*
 * Since preprocessor always operate only on the line that didn't
 * arrived yet, we should always use ERR_OFFBY1. Also since user
 * won't want to see same error twice (preprocessing is done once
 * per pass) we will want to show errors only during pass one.
 */
static void
error(int severity, char *fmt, ...)
{
    va_list arg;
    char buff[1024];

    /* If we're in a dead branch of IF or something like it, ignore the error */
    if (istk->conds && !emitting(istk->conds->state))
        return;

    va_start(arg, fmt);
    vsprintf(buff, fmt, arg);
    va_end(arg);

    if (istk->mstk && istk->mstk->name)
        __error(severity | ERR_PASS1, "(%s:%d) %s", istk->mstk->name,
                istk->mstk->lineno, buff);
    else
        __error(severity | ERR_PASS1, "%s", buff);
}

static void
pp_reset(char *file, int apass, efunc errfunc, evalfunc eval,
        ListGen * listgen)
{
    int h;

    __error = errfunc;
    cstk = NULL;
    istk = nasm_malloc(sizeof(Include));
    istk->next = NULL;
    istk->conds = NULL;
    istk->expansion = NULL;
    istk->mstk = NULL;
    istk->fp = fopen(file, "r");
    istk->fname = NULL;
    src_set_fname(nasm_strdup(file));
    src_set_linnum(0);
    istk->lineinc = 1;
    if (!istk->fp)
        error(ERR_FATAL | ERR_NOFILE, "unable to open input file `%s'", file);
    defining = NULL;
    for (h = 0; h < NHASH; h++)
    {
        mmacros[h] = NULL;
        smacros[h] = NULL;
    }
    unique = 0;
        if (tasm_compatible_mode) {
            stdmacpos = stdmac;
        } else {
                stdmacpos = &stdmac[TASM_MACRO_COUNT];
        }
    any_extrastdmac = (extrastdmac != NULL);
    list = listgen;
    evaluate = eval;
    pass = apass;
}

static char *
pp_getline(void)
{
    char *line;
    Token *tline;

    while (1)
    {
        /*
         * Fetch a tokenised line, either from the macro-expansion
         * buffer or from the input file.
         */
        tline = NULL;
        while (istk->expansion && istk->expansion->finishes)
        {
            Line *l = istk->expansion;
            if (!l->finishes->name && l->finishes->in_progress > 1)
            {
                Line *ll;

                /*
                 * This is a macro-end marker for a macro with no
                 * name, which means it's not really a macro at all
                 * but a %rep block, and the `in_progress' field is
                 * more than 1, meaning that we still need to
                 * repeat. (1 means the natural last repetition; 0
                 * means termination by %exitrep.) We have
                 * therefore expanded up to the %endrep, and must
                 * push the whole block on to the expansion buffer
                 * again. We don't bother to remove the macro-end
                 * marker: we'd only have to generate another one
                 * if we did.
                 */
                l->finishes->in_progress--;
                for (l = l->finishes->expansion; l; l = l->next)
                {
                    Token *t, *tt, **tail;

                    ll = nasm_malloc(sizeof(Line));
                    ll->next = istk->expansion;
                    ll->finishes = NULL;
                    ll->first = NULL;
                    tail = &ll->first;

                    for (t = l->first; t; t = t->next)
                    {
                        if (t->text || t->type == TOK_WHITESPACE)
                        {
                            tt = *tail = new_Token(NULL, t->type, t->text, 0);
                            tail = &tt->next;
                        }
                    }

                    istk->expansion = ll;
                }
            }
            else
            {
                /*
                 * Check whether a `%rep' was started and not ended
                 * within this macro expansion. This can happen and
                 * should be detected. It's a fatal error because
                 * I'm too confused to work out how to recover
                 * sensibly from it.
                 */
                if (defining)
                {
                    if (defining->name)
                        error(ERR_PANIC, "defining with name in expansion");
                    else if (istk->mstk->name)
                        error(ERR_FATAL, "`%%rep' without `%%endrep' within"
                                " expansion of macro `%s'", istk->mstk->name);
                }

                /*
                 * FIXME:  investigate the relationship at this point between
                 * istk->mstk and l->finishes
                 */
                {
                    MMacro *m = istk->mstk;
                    istk->mstk = m->next_active;
                    if (m->name)
                    {
                        /*
                         * This was a real macro call, not a %rep, and
                         * therefore the parameter information needs to
                         * be freed.
                         */
                        nasm_free(m->params);
                        free_tlist(m->iline);
                        nasm_free(m->paramlen);
                        l->finishes->in_progress = FALSE;
                    }
                    else
                        free_mmacro(m);
                }
                istk->expansion = l->next;
                nasm_free(l);
                list->downlevel(LIST_MACRO);
            }
        }
        while (1)
        {                       /* until we get a line we can use */

            if (istk->expansion)
            {                   /* from a macro expansion */
                char *p;
                Line *l = istk->expansion;
                if (istk->mstk)
                    istk->mstk->lineno++;
                tline = l->first;
                istk->expansion = l->next;
                nasm_free(l);
                p = detoken(tline, FALSE);
                list->line(LIST_MACRO, p);
                nasm_free(p);
                break;
            }
            line = read_line();
            if (line)
            {                   /* from the current input file */
                line = prepreproc(line);
                tline = tokenise(line);
                nasm_free(line);
                break;
            }
            /*
             * The current file has ended; work down the istk
             */
            {
                Include *i = istk;
                fclose(i->fp);
                if (i->conds)
                    error(ERR_FATAL, "expected `%%endif' before end of file");
                istk = i->next;
                list->downlevel(LIST_INCLUDE);
                src_set_linnum(i->lineno);
                nasm_free(src_set_fname(i->fname));
                nasm_free(i);
                if (!istk)
                    return NULL;
            }
        }

        /*
         * We must expand MMacro parameters and MMacro-local labels
         * _before_ we plunge into directive processing, to cope
         * with things like `%define something %1' such as STRUC
         * uses. Unless we're _defining_ a MMacro, in which case
         * those tokens should be left alone to go into the
         * definition; and unless we're in a non-emitting
         * condition, in which case we don't want to meddle with
         * anything.
         */
        if (!defining && !(istk->conds && !emitting(istk->conds->state)))
            tline = expand_mmac_params(tline);

        /*
         * Check the line to see if it's a preprocessor directive.
         */
        if (do_directive(tline) & 1)
        {
            continue;
        }
        else if (defining)
        {
            /*
             * We're defining a multi-line macro. We emit nothing
             * at all, and just
             * shove the tokenised line on to the macro definition.
             */
            Line *l = nasm_malloc(sizeof(Line));
            l->next = defining->expansion;
            l->first = tline;
            l->finishes = FALSE;
            defining->expansion = l;
            continue;
        }
        else if (istk->conds && !emitting(istk->conds->state))
        {
            /*
             * We're in a non-emitting branch of a condition block.
             * Emit nothing at all, not even a blank line: when we
             * emerge from the condition we'll give a line-number
             * directive so we keep our place correctly.
             */
            free_tlist(tline);
            continue;
        }
        else if (istk->mstk && !istk->mstk->in_progress)
        {
            /*
             * We're in a %rep block which has been terminated, so
             * we're walking through to the %endrep without
             * emitting anything. Emit nothing at all, not even a
             * blank line: when we emerge from the %rep block we'll
             * give a line-number directive so we keep our place
             * correctly.
             */
            free_tlist(tline);
            continue;
        }
        else
        {
            tline = expand_smacro(tline);
            if (!expand_mmacro(tline))
            {
                /*
                 * De-tokenise the line again, and emit it.
                 */
                line = detoken(tline, TRUE);
                free_tlist(tline);
                break;
            }
            else
            {
                continue;       /* expand_mmacro calls free_tlist */
            }
        }
    }

    return line;
}

static void
pp_cleanup(int pass)
{
    int h;

    if (defining)
    {
        error(ERR_NONFATAL, "end of file while still defining macro `%s'",
                defining->name);
        free_mmacro(defining);
    }
    while (cstk)
        ctx_pop();
    for (h = 0; h < NHASH; h++)
    {
        while (mmacros[h])
        {
            MMacro *m = mmacros[h];
            mmacros[h] = mmacros[h]->next;
            free_mmacro(m);
        }
        while (smacros[h])
        {
            SMacro *s = smacros[h];
            smacros[h] = smacros[h]->next;
            nasm_free(s->name);
            free_tlist(s->expansion);
            nasm_free(s);
        }
    }
    while (istk)
    {
        Include *i = istk;
        istk = istk->next;
        fclose(i->fp);
        nasm_free(i->fname);
        nasm_free(i);
    }
    while (cstk)
        ctx_pop();
    if (pass == 0)
        {
                free_llist(predef);
                delete_Blocks();
        }
}

void
pp_include_path(char *path)
{
    IncPath *i;

    i = nasm_malloc(sizeof(IncPath));
    i->path = nasm_strdup(path);
    i->next = ipath;
    ipath = i;
}

void
pp_pre_include(char *fname)
{
    Token *inc, *space, *name;
    Line *l;

    name = new_Token(NULL, TOK_INTERNAL_STRING, fname, 0);
    space = new_Token(name, TOK_WHITESPACE, NULL, 0);
    inc = new_Token(space, TOK_PREPROC_ID, "%include", 0);

    l = nasm_malloc(sizeof(Line));
    l->next = predef;
    l->first = inc;
    l->finishes = FALSE;
    predef = l;
}

void
pp_pre_define(char *definition)
{
    Token *def, *space;
    Line *l;
    char *equals;

    equals = strchr(definition, '=');
    space = new_Token(NULL, TOK_WHITESPACE, NULL, 0);
    def = new_Token(space, TOK_PREPROC_ID, "%define", 0);
    if (equals)
        *equals = ' ';
    space->next = tokenise(definition);
    if (equals)
        *equals = '=';

    l = nasm_malloc(sizeof(Line));
    l->next = predef;
    l->first = def;
    l->finishes = FALSE;
    predef = l;
}

void
pp_pre_undefine(char *definition)
{
    Token *def, *space;
    Line *l;

    space = new_Token(NULL, TOK_WHITESPACE, NULL, 0);
    def = new_Token(space, TOK_PREPROC_ID, "%undef", 0);

    l = nasm_malloc(sizeof(Line));
    l->next = predef;
    l->first = def;
    l->finishes = FALSE;
    predef = l;
}

void
pp_extra_stdmac(char **macros)
{
    extrastdmac = macros;
}

static void
make_tok_num(Token * tok, long val)
{
    char numbuf[20];
    sprintf(numbuf, "%ld", val);
    tok->text = nasm_strdup(numbuf);
    tok->type = TOK_NUMBER;
}

Preproc nasmpp = {
    pp_reset,
    pp_getline,
    pp_cleanup
};