From bc6424cdf290d1767fa4cb92da560bafd563c584 Mon Sep 17 00:00:00 2001
From: ketmar <ketmar@ketmar.no-ip.org>
Date: Thu, 25 Jun 2020 05:45:04 +0000
Subject: [PATCH] fixed macro argument expander (it will not drop expression
 tail anymore)

FossilOrigin-Name: 7d8537dd373a41b5ac3b0c54824a2bf5bb7eafd14ebd49b64a9fa2d2b5e08415
---
 src/urasm.c | 78 +++++++++++++++++++++++++++++++++----------------------------
 1 file changed, 42 insertions(+), 36 deletions(-)

diff --git a/src/urasm.c b/src/urasm.c
index 0302aed..04ee039 100644
--- a/src/urasm.c
+++ b/src/urasm.c
@@ -2848,12 +2848,12 @@ static int piIFX (void) { return piIFAll(1); }
 // first term char will not be skipped
 // must return pointer to the first char after expression end
 static const char *getValueCB (urasm_exprval_t *res, const char *expr, uint16_t addr, int donteval, int *defined, int *error) {
-  char name[257], *p = name;
-  //
+  char name[257];
+  char *p = name;
+
   if (curmacro == NULL) fatal("'=' outside of macro");
   if (*expr++ != '=') fatal("'=' expected!");
-  //fprintf(stderr, "GV: [%s]\n", expr);
-  //
+
   expr = strSkipSpaces(expr);
   while (*expr) {
     if (isAlphaDigit(*expr) || *expr == '_') {
@@ -2864,14 +2864,14 @@ static const char *getValueCB (urasm_exprval_t *res, const char *expr, uint16_t
     break;
   }
   *p = 0;
+
   expr = strSkipSpaces(expr);
   for (int f = 0; f < curmacro->mac->argc; ++f) {
     if (strcasecmp(name, curmacro->mac->argnames[f]) == 0) {
       if (*expr == '[') {
         urasm_exprval_t v;
-        int l = strlen(curmacro->argvals[f]);
-        //
-        ++expr;
+        int l = (int)strlen(curmacro->argvals[f]);
+        ++expr; // skip "["
         urasm_exprval_init(&v);
         expr = urasm_expr_ex(&v, expr, addr, &donteval, defined, error);
         if (*error) return expr;
@@ -2886,24 +2886,27 @@ static const char *getValueCB (urasm_exprval_t *res, const char *expr, uint16_t
         return expr;
       } else {
         urasm_expr_ex(res, curmacro->argvals[f], addr, &donteval, defined, error);
-        //fprintf(stderr, "GV: [%s] [%s] [%d]\n", name, curmacro->argvals[f], res->val);
         return expr;
       }
     }
   }
+
   fatal("unknown macro variable: '%s'", name);
 }
 
 
 //!0: error; oprlen is opr size (w/o ending 0), it's 255 for now
+// opr starts with '=' (invariant)
 static int expandCB (char *opr, int oprlen) {
   char name[257], *p = name, *op = opr;
-  //
+
   if (curmacro == NULL) fatal("'=' outside of macro");
-  if (*op++ != '=') fatal("'=' expected!");
+  if (*op++ != '=') fatal("'=' expected!"); // just in case
   //fprintf(stderr, "expand: [%s]\n", opr);
-  //fatal("!!!");
-  op = strSkipSpaces(op);
+
+  if (!isAlpha(op[0])) return 0; // nothing to do
+
+  // copy argument name
   while (*op) {
     if (isAlphaDigit(*op) || *op == '_') {
       if (p-name > 250) fatal("id too long");
@@ -2913,35 +2916,38 @@ static int expandCB (char *opr, int oprlen) {
     break;
   }
   *p = 0;
+
+  // expand argument? we only need to expand `=arg[n]`
   op = strSkipSpaces(op);
+  if (op[0] != '[') return 0;
+
   for (int f = 0; f < curmacro->mac->argc; ++f) {
     if (strcasecmp(name, curmacro->mac->argnames[f]) == 0) {
-      if (*op == '[') {
-        urasm_exprval_t v;
-        int l = strlen(curmacro->argvals[f]), error = 0, defined = 1, donteval = 0;
-        //
-        ++op;
-        urasm_exprval_init(&v);
-        op = (char *)urasm_expr_ex(&v, op, pc, &donteval, &defined, &error);
-        if (error) return -1;
-        if (op == NULL || *op != ']' || v.str != NULL) return -1;
-        op = strSkipSpaces(op+1);
-        if (*op) return -1;
-        if (v.val < 0) v.val += l;
-        if (v.val < 0 || v.val >= l) {
-          strcpy(opr, "?");
-        } else {
-          opr[0] = curmacro->argvals[f][v.val];
-          opr[1] = 0;
-        }
-        return 0;
-      }
-      //
-      strncpy(opr, curmacro->argvals[f], oprlen);
-      opr[oprlen-1] = 0;
-      return (*op ? -1 : 0);
+      if (*op != '[') abort(); // assertion, just in case
+      // replace argument with character
+      // used for `=regpair[0]`
+      urasm_exprval_t v;
+      int error = 0, defined = 1, donteval = 0;
+      ++op; // skip '['
+      urasm_exprval_init(&v);
+      op = (char *)urasm_expr_ex(&v, op, pc, &donteval, &defined, &error);
+      if (error) return -1;
+      // result should be a number
+      if (op == NULL || *op != ']' || v.str != NULL) return -1;
+      ++op; // skip ']'
+      // it is guaranteed to have more than one char in opr
+      // so we can simply put char from argument value, and remove other expression chars
+      const int l = (int)strlen(curmacro->argvals[f]);
+      if (v.val < 0) v.val += l; // negative: indexing from the end
+      if (v.val < 0 || v.val >= l) fatal("index %d is out of bounds for macro argument '%s'", v.val, curmacro->mac->argnames[f]);
+      // copy char
+      opr[0] = curmacro->argvals[f][v.val];
+      // remove other chars
+      memmove(opr+1, op, strlen(op)+1);
+      return 0;
     }
   }
+
   fatal("unknown macro variable: '%s'", name);
 }
 
-- 
2.11.4.GIT