/*
 * C version of 9_9_1.x68
 *
 * Converts an ASCII string-representation of a decimal number to binary.  It
 * lacks the error detection that assembly allows.
 */

#include "stdio.h"

unsigned short ascii_to_bcd(char * ascii, char * bcdspc) {
  unsigned short n = 0;
  for(;;++n) {
    char c = *ascii++;
    if (!c) break;
    c -= 0x30;
    *bcdspc++ = c;
  }
  return n;
}

long bcd_to_binary(unsigned short n, char * bcdspc) {
  long acc = 0;
  unsigned short i;
  for(i = 0; i < n; ++i) {
    // should catch overflows, possible in assembly
    acc *= 10;
    acc += (unsigned long) bcdspc[i];
  }
  return acc;
}

static char * ASCIIEX = "1979";
static char BCDSPC[256];

int main(char ** args, int argv) {
  unsigned short n;
  long d;
  n = ascii_to_bcd(ASCIIEX, BCDSPC);
  d = bcd_to_binary(n, BCDSPC);
  printf("%d\n", d);
}