asc2bin.c

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <ctype.h>

uint8_t getNibble(char ascii) {
   uint8_t nibble = 0;
   if (ascii >= '0' && ascii <= '9') {
      nibble = (uint8_t)(ascii - '0');
   } else if (toupper(ascii) >= 'A' || toupper(ascii) <= 'F') {
      nibble = (uint8_t)(toupper(ascii) - 'A') + 0xA;
   }

   return nibble;
}

void main(int argc, char **argv) {
   FILE *ifp;
   FILE *ofp;

   int address;
   char idata[1003]; // Max 1000 ASCII characters + end of line and null terminator
   uint8_t odata;
   int i;
   uint8_t nibble;

   if (argc < 3) {
      printf("Usage: %s [source ASCII file] [converted binary file] [default load address]\n", argv[0]);
      return;
   }

   ifp = fopen(argv[1], "r");
   if (ifp == NULL) {
      printf("Error opening %s for reading\n", argv[1]);
      return;
   }
   ofp = fopen(argv[2], "w");
   if (ofp == NULL) {
      printf("Error opening %s for writing\n", argv[2]);
      return;
   }

   if (argc >= 4) {
      sscanf(argv[3],"%x",&address);
   } else {
      // set default load address to 0x0000
      address = 0x0000;
   }

   odata = (uint8_t) (address & 0x00FF);
   fwrite(&odata,1,1,ofp);
   odata = (uint8_t) ((address & 0xFF00) >> 8);
   fwrite(&odata,1,1,ofp);

   while (!feof(ifp)) {
      if (fgets(idata, 1001, ifp) != NULL) {
         if (idata[0] != '#') {
            i = 0;
            while ((idata[i] >= ' ') && (idata[i] != '#')) {
               if (idata[i] == ' ') {
                  i++;
               } else {
                  nibble = getNibble(idata[i]);
                  odata = nibble << 4;
                  nibble = getNibble(idata[i+1]);
                  odata = odata | nibble;
                  fwrite(&odata,1,1,ofp);
                  i += 2;
               }
            }
         }
      }
   }
}