Add version number to the cover page, generated from the version file.

[nasm.git] / parser.c

/* parser.c   source line parser 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 27/iii/95 by Simon Tatham
 */

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

#include "nasm.h"
#include "nasmlib.h"
#include "parser.h"
#include "float.h"

static long reg_flags[] = {            /* sizes and special flags */
    0, REG8, REG_AL, REG_AX, REG8, REG8, REG16, REG16, REG8, REG_CL,
    REG_CREG, REG_CREG, REG_CREG, REG_CR4, REG_CS, REG_CX, REG8,
    REG16, REG8, REG_DREG, REG_DREG, REG_DREG, REG_DREG, REG_DREG,
    REG_DREG, REG_DESS, REG_DX, REG_EAX, REG32, REG32, REG_ECX,
    REG32, REG32, REG_DESS, REG32, REG32, REG_FSGS, REG_FSGS,
    MMXREG, MMXREG, MMXREG, MMXREG, MMXREG, MMXREG, MMXREG, MMXREG,
    REG16, REG16, REG_DESS, FPU0, FPUREG, FPUREG, FPUREG, FPUREG,
    FPUREG, FPUREG, FPUREG, REG_TREG, REG_TREG, REG_TREG, REG_TREG,
    REG_TREG,
    XMMREG, XMMREG, XMMREG, XMMREG, XMMREG, XMMREG, XMMREG, XMMREG
};

enum {                                 /* special tokens */
    S_BYTE, S_DWORD, S_FAR, S_LONG, S_NEAR, S_NOSPLIT, S_QWORD,
    S_SHORT, S_TO, S_TWORD, S_WORD
};

static int is_comma_next (void);

static int i;
static struct tokenval tokval;
static efunc error;
static struct ofmt *outfmt;  /* Structure of addresses of output routines */
static loc_t *location;      /* Pointer to current line's segment,offset */

void parser_global_info (struct ofmt *output, loc_t *locp) 
{
    outfmt = output;
    location = locp;
}

insn *parse_line (int pass, char *buffer, insn *result,
                  efunc errfunc, evalfunc evaluate, ldfunc ldef) 
{
    int operand;
    int critical;
    struct eval_hints hints;

    result->forw_ref = FALSE;
    error = errfunc;

    stdscan_reset();
    stdscan_bufptr = buffer;
    i = stdscan(NULL, &tokval);

    result->label = NULL;              /* Assume no label */
    result->eops = NULL;               /* must do this, whatever happens */
    result->operands = 0;              /* must initialise this */

    if (i==0) {                        /* blank line - ignore */
        result->opcode = -1;           /* and no instruction either */
        return result;
    }
    if (i != TOKEN_ID && i != TOKEN_INSN && i != TOKEN_PREFIX &&
        (i!=TOKEN_REG || (REG_SREG & ~reg_flags[tokval.t_integer]))) {
        error (ERR_NONFATAL, "label or instruction expected"
               " at start of line");
        result->opcode = -1;
        return result;
    }

    if (i == TOKEN_ID) {               /* there's a label here */
        result->label = tokval.t_charptr;
        i = stdscan(NULL, &tokval);
        if (i == ':') {                /* skip over the optional colon */
            i = stdscan(NULL, &tokval);
        } else if (i == 0) {
            error (ERR_WARNING|ERR_WARN_OL|ERR_PASS1,
                   "label alone on a line without a colon might be in error");
        }
        if (i != TOKEN_INSN || tokval.t_integer != I_EQU)
        {
            /*
             * FIXME: location->segment could be NO_SEG, in which case
             * it is possible we should be passing 'abs_seg'. Look into this.
             * Work out whether that is *really* what we should be doing.
             * Generally fix things. I think this is right as it is, but
             * am still not certain.
             */
            ldef (result->label, location->segment,
                  location->offset, NULL, TRUE, FALSE, outfmt, errfunc);
        }
    }

    if (i==0) {
        result->opcode = -1;           /* this line contains just a label */
        return result;
    }

    result->nprefix = 0;
    result->times = 1L;

    while (i == TOKEN_PREFIX ||
           (i==TOKEN_REG && !(REG_SREG & ~reg_flags[tokval.t_integer]))) 
    {
        /*
         * Handle special case: the TIMES prefix.
         */
        if (i == TOKEN_PREFIX && tokval.t_integer == P_TIMES) {
            expr *value;

            i = stdscan(NULL, &tokval);
            value = evaluate (stdscan, NULL, &tokval, NULL, pass0, error, NULL);
            i = tokval.t_type;
            if (!value) {              /* but, error in evaluator */
                result->opcode = -1;   /* unrecoverable parse error: */
                return result;         /* ignore this instruction */
            }
            if (!is_simple (value)) {
                error (ERR_NONFATAL,
                       "non-constant argument supplied to TIMES");
                result->times = 1L;
            } else {
                result->times = value->value;
                if (value->value < 0) {
                    error(ERR_NONFATAL, "TIMES value %d is negative",
                          value->value);
                    result->times = 0;
                }
            }
        } else {
            if (result->nprefix == MAXPREFIX)
                error (ERR_NONFATAL,
                       "instruction has more than %d prefixes", MAXPREFIX);
            else
                result->prefixes[result->nprefix++] = tokval.t_integer;
            i = stdscan(NULL, &tokval);
        }
    }

    if (i != TOKEN_INSN) {
        if (result->nprefix > 0 && i == 0) {
            /*
             * Instruction prefixes are present, but no actual
             * instruction. This is allowed: at this point we
             * invent a notional instruction of RESB 0.
             */
            result->opcode = I_RESB;
            result->operands = 1;
            result->oprs[0].type = IMMEDIATE;
            result->oprs[0].offset = 0L;
            result->oprs[0].segment = result->oprs[0].wrt = NO_SEG;
            return result;
        } else {
            error (ERR_NONFATAL, "parser: instruction expected");
            result->opcode = -1;
            return result;
        }
    }

    result->opcode = tokval.t_integer;
    result->condition = tokval.t_inttwo;

    /*
     * RESB, RESW and RESD cannot be satisfied with incorrectly
     * evaluated operands, since the correct values _must_ be known
     * on the first pass. Hence, even in pass one, we set the
     * `critical' flag on calling evaluate(), so that it will bomb
     * out on undefined symbols. Nasty, but there's nothing we can
     * do about it.
     *
     * For the moment, EQU has the same difficulty, so we'll
     * include that.
     */
    if (result->opcode == I_RESB ||
        result->opcode == I_RESW ||
        result->opcode == I_RESD ||
        result->opcode == I_RESQ ||
        result->opcode == I_REST ||
        result->opcode == I_EQU ||
        result->opcode == I_INCBIN)  /* fbk */
    {
        critical = pass0;
    }
    else
        critical = (pass==2 ? 2 : 0);

    if (result->opcode == I_DB ||
        result->opcode == I_DW ||
        result->opcode == I_DD ||
        result->opcode == I_DQ ||
        result->opcode == I_DT ||
        result->opcode == I_INCBIN) 
    {
        extop *eop, **tail = &result->eops, **fixptr;
        int oper_num = 0;

        result->eops_float = FALSE;

        /*
         * Begin to read the DB/DW/DD/DQ/DT/INCBIN operands.
         */
        while (1) {
            i = stdscan(NULL, &tokval);
            if (i == 0)
                break;
            fixptr = tail;
            eop = *tail = nasm_malloc(sizeof(extop));
            tail = &eop->next;
            eop->next = NULL;
            eop->type = EOT_NOTHING;
            oper_num++;

            if (i == TOKEN_NUM && tokval.t_charptr && is_comma_next()) {
                eop->type = EOT_DB_STRING;
                eop->stringval = tokval.t_charptr;
                eop->stringlen = tokval.t_inttwo;
                i = stdscan(NULL, &tokval);       /* eat the comma */
                continue;
            }

            if ((i == TOKEN_FLOAT && is_comma_next()) || i == '-') {
                long sign = +1L;

                if (i == '-') {
                    char *save = stdscan_bufptr;
                    i = stdscan(NULL, &tokval);
                    sign = -1L;
                    if (i != TOKEN_FLOAT || !is_comma_next()) {
                        stdscan_bufptr = save;
                        i = tokval.t_type = '-';
                    }
                }

                if (i == TOKEN_FLOAT) {
                    eop->type = EOT_DB_STRING;
                    result->eops_float = TRUE;
                    if (result->opcode == I_DD)
                        eop->stringlen = 4;
                    else if (result->opcode == I_DQ)
                        eop->stringlen = 8;
                    else if (result->opcode == I_DT)
                        eop->stringlen = 10;
                    else {
                        error(ERR_NONFATAL, "floating-point constant"
                              " encountered in `D%c' instruction",
                              result->opcode == I_DW ? 'W' : 'B');
                        /*
                         * fix suggested by Pedro Gimeno... original line
                         * was:
                         * eop->type = EOT_NOTHING;
                         */
                        eop->stringlen = 0;
                    }
                    eop = nasm_realloc(eop, sizeof(extop)+eop->stringlen);
                    tail = &eop->next;
                    *fixptr = eop;
                    eop->stringval = (char *)eop + sizeof(extop);
                    if (eop->stringlen < 4 ||
                        !float_const (tokval.t_charptr, sign,
                                      (unsigned char *)eop->stringval,
                                      eop->stringlen, error))
                        eop->type = EOT_NOTHING;
                    i = stdscan(NULL, &tokval);       /* eat the comma */
                    continue;
                }
            }

            /* anything else */ 
            {
                expr *value;
                value = evaluate (stdscan, NULL, &tokval, NULL,
                                  critical, error, NULL);
                i = tokval.t_type;
                if (!value) {          /* error in evaluator */
                    result->opcode = -1;/* unrecoverable parse error: */
                    return result;     /* ignore this instruction */
                }
                if (is_unknown(value)) {
                    eop->type = EOT_DB_NUMBER;
                    eop->offset = 0;   /* doesn't matter what we put */
                    eop->segment = eop->wrt = NO_SEG;   /* likewise */
                } else if (is_reloc(value)) {
                    eop->type = EOT_DB_NUMBER;
                    eop->offset = reloc_value(value);
                    eop->segment = reloc_seg(value);
                    eop->wrt = reloc_wrt(value);
                } else {
                    error (ERR_NONFATAL,
                           "operand %d: expression is not simple"
                           " or relocatable", oper_num);
                }
            }

            /*
             * We're about to call stdscan(), which will eat the
             * comma that we're currently sitting on between
             * arguments. However, we'd better check first that it
             * _is_ a comma.
             */
            if (i == 0)                /* also could be EOL */
                break;
            if (i != ',') {
                error (ERR_NONFATAL, "comma expected after operand %d",
                       oper_num);
                result->opcode = -1;/* unrecoverable parse error: */
                return result;     /* ignore this instruction */
            }
        }

        if (result->opcode == I_INCBIN) {
            /*
             * Correct syntax for INCBIN is that there should be
             * one string operand, followed by one or two numeric
             * operands.
             */
            if (!result->eops || result->eops->type != EOT_DB_STRING)
                error (ERR_NONFATAL, "`incbin' expects a file name");
            else if (result->eops->next &&
                     result->eops->next->type != EOT_DB_NUMBER)
                error (ERR_NONFATAL, "`incbin': second parameter is",
                       " non-numeric");
            else if (result->eops->next && result->eops->next->next &&
                     result->eops->next->next->type != EOT_DB_NUMBER)
                error (ERR_NONFATAL, "`incbin': third parameter is",
                       " non-numeric");
            else if (result->eops->next && result->eops->next->next &&
                     result->eops->next->next->next)
                error (ERR_NONFATAL, "`incbin': more than three parameters");
            else
                return result;
            /*
             * If we reach here, one of the above errors happened.
             * Throw the instruction away.
             */
            result->opcode = -1;
            return result;
        } else /* DB ... */
            if (oper_num == 0)
                error (ERR_WARNING|ERR_PASS1,
                       "no operand for data declaration");
            else
                result->operands = oper_num;

        return result;
    }

    /* right. Now we begin to parse the operands. There may be up to three
     * of these, separated by commas, and terminated by a zero token. */

    for (operand = 0; operand < 3; operand++) {
        expr *value;                   /* used most of the time */
        int mref;                      /* is this going to be a memory ref? */
        int bracket;                   /* is it a [] mref, or a & mref? */
        int setsize = 0;

        result->oprs[operand].addr_size = 0;/* have to zero this whatever */
        result->oprs[operand].eaflags = 0;   /* and this */
        result->oprs[operand].opflags = 0;

        i = stdscan(NULL, &tokval);
        if (i == 0) break;             /* end of operands: get out of here */
        result->oprs[operand].type = 0;   /* so far, no override */
        while (i == TOKEN_SPECIAL)      {/* size specifiers */
            switch ((int)tokval.t_integer) {
              case S_BYTE:
                if (!setsize)            /* we want to use only the first */
                    result->oprs[operand].type |= BITS8;
                setsize = 1;
                break;
              case S_WORD:
                if (!setsize)
                    result->oprs[operand].type |= BITS16;
                setsize = 1;
                break;
              case S_DWORD:
              case S_LONG:
                if (!setsize)
                    result->oprs[operand].type |= BITS32;
                setsize = 1;
                break;
              case S_QWORD:
                if (!setsize)
                    result->oprs[operand].type |= BITS64;
                setsize = 1;
                break;
              case S_TWORD:
                if (!setsize)
                    result->oprs[operand].type |= BITS80;
                setsize = 1;
                break;
              case S_TO:
                result->oprs[operand].type |= TO;
                break;
              case S_FAR:
                result->oprs[operand].type |= FAR;
                break;
              case S_NEAR:
                result->oprs[operand].type |= NEAR;
                break;
              case S_SHORT:
                result->oprs[operand].type |= SHORT;
                break;
              default:
                error (ERR_NONFATAL, "invalid operand size specification");
            }
            i = stdscan(NULL, &tokval);
        }

        if (i == '[' || i == '&') {    /* memory reference */
            mref = TRUE;
            bracket = (i == '[');
            i = stdscan(NULL, &tokval);
            if (i == TOKEN_SPECIAL) {  /* check for address size override */
                if (tasm_compatible_mode) {
                  switch ((int)tokval.t_integer) {
                    /* For TASM compatibility a size override inside the
                     * brackets changes the size of the operand, not the
                     * address type of the operand as it does in standard
                     * NASM syntax. Hence:
                     *
                     *  mov     eax,[DWORD val]
                     *
                     * is valid syntax in TASM compatibility mode. Note that
                     * you lose the ability to override the default address
                     * type for the instruction, but we never use anything
                     * but 32-bit flat model addressing in our code.
                     */
                    case S_BYTE:
                      result->oprs[operand].type |= BITS8;
                      break;
                    case S_WORD:
                      result->oprs[operand].type |= BITS16;
                      break;
                    case S_DWORD:
                    case S_LONG:
                      result->oprs[operand].type |= BITS32;
                      break;
                    case S_QWORD:
                      result->oprs[operand].type |= BITS64;
                      break;
                    case S_TWORD:
                      result->oprs[operand].type |= BITS80;
                      break;
                    default:
                      error (ERR_NONFATAL, "invalid operand size specification");
                  }
                } else {
                  /* Standard NASM compatible syntax */
                  switch ((int)tokval.t_integer) {
                    case S_NOSPLIT:
                      result->oprs[operand].eaflags |= EAF_TIMESTWO;
                      break;
                    case S_BYTE:
                      result->oprs[operand].eaflags |= EAF_BYTEOFFS;
                      break;
                    case S_WORD:
                      result->oprs[operand].addr_size = 16;
                      result->oprs[operand].eaflags |= EAF_WORDOFFS;
                      break;
                    case S_DWORD:
                    case S_LONG:
                      result->oprs[operand].addr_size = 32;
                      result->oprs[operand].eaflags |= EAF_WORDOFFS;
                      break;
                    default:
                      error (ERR_NONFATAL, "invalid size specification in"
                             " effective address");
                  }
                }
                i = stdscan(NULL, &tokval);
            }
        } else {                       /* immediate operand, or register */
            mref = FALSE;
            bracket = FALSE;           /* placate optimisers */
        }

        value = evaluate (stdscan, NULL, &tokval,
                          &result->oprs[operand].opflags,
                          critical, error, &hints);
        i = tokval.t_type;
        if (result->oprs[operand].opflags & OPFLAG_FORWARD) {
            result->forw_ref = TRUE;
        }
        if (!value) {                  /* error in evaluator */
            result->opcode = -1;       /* unrecoverable parse error: */
            return result;             /* ignore this instruction */
        }
        if (i == ':' && mref) {        /* it was seg:offset */
            /*
             * Process the segment override.
             */
            if (value[1].type!=0 || value->value!=1 ||
                REG_SREG & ~reg_flags[value->type])
                error (ERR_NONFATAL, "invalid segment override");
            else if (result->nprefix == MAXPREFIX)
                error (ERR_NONFATAL,
                       "instruction has more than %d prefixes",
                       MAXPREFIX);
            else
                result->prefixes[result->nprefix++] = value->type;

            i = stdscan(NULL, &tokval);        /* then skip the colon */
            if (i == TOKEN_SPECIAL) {  /* another check for size override */
                switch ((int)tokval.t_integer) {
                  case S_WORD:
                    result->oprs[operand].addr_size = 16;
                    break;
                  case S_DWORD:
                  case S_LONG:
                    result->oprs[operand].addr_size = 32;
                    break;
                  default:
                    error (ERR_NONFATAL, "invalid size specification in"
                           " effective address");
                }
                i = stdscan(NULL, &tokval);
            }
            value = evaluate (stdscan, NULL, &tokval,
                              &result->oprs[operand].opflags,
                              critical, error, &hints);
            i = tokval.t_type;
            if (result->oprs[operand].opflags & OPFLAG_FORWARD) {
                result->forw_ref = TRUE;
            }
            /* and get the offset */
            if (!value) {              /* but, error in evaluator */
                result->opcode = -1;   /* unrecoverable parse error: */
                return result;         /* ignore this instruction */
            }
        }
        if (mref && bracket) {         /* find ] at the end */
            if (i != ']') {
                error (ERR_NONFATAL, "parser: expecting ]");
                do {                   /* error recovery again */
                    i = stdscan(NULL, &tokval);
                } while (i != 0 && i != ',');
            } else                     /* we got the required ] */
                i = stdscan(NULL, &tokval);
        } else {                       /* immediate operand */
            if (i != 0 && i != ',' && i != ':') {
                error (ERR_NONFATAL, "comma or end of line expected");
                do {                   /* error recovery */
                    i = stdscan(NULL, &tokval);
                } while (i != 0 && i != ',');
            } else if (i == ':') {
                result->oprs[operand].type |= COLON;
            }
        }

        /* now convert the exprs returned from evaluate() into operand
         * descriptions... */

        if (mref) {                    /* it's a memory reference */
            expr *e = value;
            int b, i, s;               /* basereg, indexreg, scale */
            long o;                    /* offset */

            b = i = -1, o = s = 0;
            result->oprs[operand].hintbase = hints.base;
            result->oprs[operand].hinttype = hints.type;

            if (e->type <= EXPR_REG_END) {   /* this bit's a register */
                if (e->value == 1) /* in fact it can be basereg */
                    b = e->type;
                else           /* no, it has to be indexreg */
                    i = e->type, s = e->value;
                e++;
            }
            if (e->type && e->type <= EXPR_REG_END)   /* it's a 2nd register */
            {
                if (b != -1)               /* If the first was the base, ... */
                    i = e->type, s = e->value;  /* second has to be indexreg */

                else if (e->value != 1)          /* If both want to be index */
                {
                    error(ERR_NONFATAL, "beroset-p-592-invalid effective address");
                    result->opcode = -1;
                    return result;
                } 
                else
                    b = e->type;
                e++;
            }
            if (e->type != 0) {        /* is there an offset? */
                if (e->type <= EXPR_REG_END)  /* in fact, is there an error? */
                {
                    error (ERR_NONFATAL, "beroset-p-603-invalid effective address");
                    result->opcode = -1;
                    return result;
                } 
                else 
                {
                    if (e->type == EXPR_UNKNOWN) {
                        o = 0;                       /* doesn't matter what */
                        result->oprs[operand].wrt = NO_SEG;     /* nor this */
                        result->oprs[operand].segment = NO_SEG;  /* or this */
                        while (e->type) e++;   /* go to the end of the line */
                    } 
                    else 
                    {
                        if (e->type == EXPR_SIMPLE) {
                            o = e->value;
                            e++;
                        }
                        if (e->type == EXPR_WRT) {
                            result->oprs[operand].wrt = e->value;
                            e++;
                        } else
                            result->oprs[operand].wrt = NO_SEG;
                        /*
                         * Look for a segment base type.
                         */
                        if (e->type && e->type < EXPR_SEGBASE) {
                            error (ERR_NONFATAL, "beroset-p-630-invalid effective address");
                            result->opcode = -1;
                            return result;
                        }
                        while (e->type && e->value == 0)
                            e++;
                        if (e->type && e->value != 1) {
                            error (ERR_NONFATAL, "beroset-p-637-invalid effective address");
                            result->opcode = -1;
                            return result;
                        }
                        if (e->type) {
                            result->oprs[operand].segment =
                                e->type - EXPR_SEGBASE;
                            e++;
                        } else
                            result->oprs[operand].segment = NO_SEG;
                        while (e->type && e->value == 0)
                            e++;
                        if (e->type) {
                            error (ERR_NONFATAL, "beroset-p-650-invalid effective address");
                            result->opcode = -1;
                            return result;
                        }
                    }
                }
            } else {
                o = 0;
                result->oprs[operand].wrt = NO_SEG;
                result->oprs[operand].segment = NO_SEG;
            }

            if (e->type != 0) {    /* there'd better be nothing left! */
                error (ERR_NONFATAL, "beroset-p-663-invalid effective address");
                result->opcode = -1;
                return result;
            }

            result->oprs[operand].type |= MEMORY;
            if (b==-1 && (i==-1 || s==0))
                result->oprs[operand].type |= MEM_OFFS;
            result->oprs[operand].basereg = b;
            result->oprs[operand].indexreg = i;
            result->oprs[operand].scale = s;
            result->oprs[operand].offset = o;
        } 
        else                                  /* it's not a memory reference */
        {
            if (is_just_unknown(value)) {     /* it's immediate but unknown */
                result->oprs[operand].type |= IMMEDIATE;
                result->oprs[operand].offset = 0;   /* don't care */
                result->oprs[operand].segment = NO_SEG; /* don't care again */
                result->oprs[operand].wrt = NO_SEG;/* still don't care */
            } 
            else if (is_reloc(value))         /* it's immediate */
            {
                result->oprs[operand].type |= IMMEDIATE;
                result->oprs[operand].offset = reloc_value(value);
                result->oprs[operand].segment = reloc_seg(value);
                result->oprs[operand].wrt = reloc_wrt(value);
                if (is_simple(value)) {
                    if (reloc_value(value)==1)
                        result->oprs[operand].type |= UNITY;
                    if (optimizing>=0) {
                        if (reloc_value(value) >= -128 &&
                                 reloc_value(value) <= 127)
                            result->oprs[operand].type |= SBYTE;
                    }
                }
            } 
            else               /* it's a register */
            {
                if (value->type>=EXPR_SIMPLE || value->value!=1) {
                    error (ERR_NONFATAL, "invalid operand type");
                    result->opcode = -1;
                    return result;
                }

                /*
                 * check that its only 1 register, not an expression...
                 */
                for (i = 1; value[i].type; i++)
                    if (value[i].value) {
                        error (ERR_NONFATAL, "invalid operand type");
                        result->opcode = -1;
                        return result;
                    }

                /* clear overrides, except TO which applies to FPU regs */
                if (result->oprs[operand].type & ~TO) {
                    /*
                     * we want to produce a warning iff the specified size
                     * is different from the register size
                     */
                    i = result->oprs[operand].type & SIZE_MASK;
                }
                else
                    i = 0;

                result->oprs[operand].type &= TO;
                result->oprs[operand].type |= REGISTER;
                result->oprs[operand].type |= reg_flags[value->type];
                result->oprs[operand].basereg = value->type;

                if (i && (result->oprs[operand].type & SIZE_MASK) != i)
                    error (ERR_WARNING|ERR_PASS1,
                           "register size specification ignored");
            }
        }
    }

    result->operands = operand;       /* set operand count */

    while (operand<3)                  /* clear remaining operands */
        result->oprs[operand++].type = 0;

    /*
     * Transform RESW, RESD, RESQ, REST into RESB.
     */
    switch (result->opcode) {
      case I_RESW: result->opcode=I_RESB; result->oprs[0].offset*=2; break;
      case I_RESD: result->opcode=I_RESB; result->oprs[0].offset*=4; break;
      case I_RESQ: result->opcode=I_RESB; result->oprs[0].offset*=8; break;
      case I_REST: result->opcode=I_RESB; result->oprs[0].offset*=10; break;
    }

    return result;
}

static int is_comma_next (void) 
{
    char *p;
    int i;
    struct tokenval tv;

    p = stdscan_bufptr;
    i = stdscan (NULL, &tv);
    stdscan_bufptr = p;
    return (i == ',' || i == ';' || !i);
}

void cleanup_insn (insn *i) 
{
    extop *e;

    while (i->eops) {
        e = i->eops;
        i->eops = i->eops->next;
        nasm_free (e);
    }
}