pet-projects/DLW-1e/das/pass1.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <ctype.h>
   4 #include <assert.h>
   5 #include <errno.h>
   6
   7 #include "pass1.h"
   8 #include "file.h"
   9 #include "symbol_tbl.h"
  10 #include "error.h"
  11
  12 static char *read_label(char *line, int lcount, int line_nr, int *pass1_error)
  13 {
  14         int err;
  15         size_t len;
  16         char *p, label[LABEL_LEN];
  17
  18         p = strchr(line, ':');
  19         if (!p)
  20                 return line;
  21
  22         len = p - line;
  23         if (len >= (sizeof(label) - 1)) {
  24                 error(line_nr, "label is too big");
  25                 *pass1_error = 1;
  26         }
  27
  28         *p++ = '\0';
  29
  30         if (*pass1_error == 0) {
  31                 memset(label, 0, sizeof(label));
  32                 strncpy(label, line, sizeof(label) - 1);
  33                 err = symbol_tbl_insert(label, lcount, line_nr);
  34                 if (err)
  35                         *pass1_error = 1;
  36         }
  37
  38         return skip_spaces(p, strlen(p));
  39 }
  40
  41 /* das_pass1()
  42  *
  43  * Perform assembler first pass
  44  *
  45  *     o Populates the symbol table
  46  *     o Remove prefixed spaces
  47  *     o Remove labels
  48  *
  49  * asmfp: asm FILE pointer (input)
  50  * interfp: intermediate FILE pointer (output)
  51  * debug: debug mode
  52  */
  53 int das_pass1(FILE *asmfp, FILE *interfp, int debug)
  54 {
  55         char line[DEF_LINE_LEN], *p;
  56         int line_nr, lcount, err, ret;
  57
  58         err = lcount = 0;
  59
  60         for (line_nr = 1;; line_nr++) {
  61                 ret = file_read_line(asmfp, line, DEF_LINE_LEN);
  62                 if (ret == 1)
  63                         break;
  64
  65                 p = skip_spaces(line, strlen(line));
  66                 if (!p)
  67                         p = line;
  68
  69                 p = read_label(p, lcount, line_nr, &err);
  70
  71                 assert(p != NULL);
  72
  73                 ret = fprintf(interfp, "%s", p);
  74                 if (ret < 0) {
  75                         fatal("pass1 could not write to file: %s",
  76                               strerror(errno));
  77                 }
  78
  79                 if (isalpha(*p))
  80                         lcount += 2;
  81         }
  82
  83         if (debug)
  84                 symbol_tbl_dump();
  85
  86         return err;
  87 }