rdf2ihx.c

开源的nasm编译器源码,研究编译器原理很有帮且

/* rdf2ihx: convert an RDOFF object file to Intel Hex format.  This is based
   on rdf2bin.  Note that this program only writes 16-bit HEX. */

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

#include "rdfload.h"
#include "rdoff.h"
#include "nasmlib.h"
#include "symtab.h"

long origin = 0;
int align = 16;

/* This function writes a single n-byte data record to of.  Maximum value
   for n is 255. */
static int write_data_record(FILE *of, int ofs, int nbytes,
			     unsigned char *data)
{
  int i, iofs;
  unsigned int checksum;

  iofs = ofs;
  fprintf(of, ":%02X%04X00", nbytes, ofs);
  checksum = 0;
  for (i=0; i<nbytes; i++) {
    fprintf(of, "%02X", data[i]);
    ofs++;
    checksum += data[i];
  }
  checksum = checksum +		/* current checksum */
    nbytes +			/* RECLEN (one byte) */
    ((iofs >> 8) & 0xff) +	/* high byte of load offset */
    (iofs & 0xff);		/* low byte of load offset */
  checksum = ~checksum + 1;
  fprintf(of, "%02X\n", checksum&0xff);
  return(ofs);
}

int main(int argc, char **argv)
{
  rdfmodule *m;
  int tmp;
  FILE *of;
  char *padding;
  unsigned char *segbin[2];
  int pad[2], segn, ofs, i;
  long segaddr;
  unsigned int checksum;
  symtabEnt *s;

  if (argc < 2) {
    puts("Usage: rdf2ihx [-o relocation-origin] [-p segment-alignment] "
	 "input-file  output-file");
    return(1);
  }

  argv++, argc--;

  while (argc > 2) {
    if (strcmp(*argv,"-o") == 0) {
      argv++, argc--;
      origin = readnum(*argv, &tmp);
      if (tmp) {
	fprintf(stderr,"rdf2ihx: invalid parameter: %s\n",*argv);
	return 1;
      }
    } else if (strcmp(*argv,"-p") == 0) {
      argv++, argc--;
      align = readnum(*argv, &tmp);
      if (tmp) {
	fprintf(stderr,"rdf2ihx: invalid parameter: %s\n",*argv);
	return 1;
      }
    } else 
      break;
    argv++, argc--;
  }
  if (argc < 2) {
    puts("rdf2ihx: required parameter missing");
    return -1;
  }
  m = rdfload(*argv);

  if (!m) {
    rdfperror("rdf2ihx",*argv);
    return 1;
  }
  printf("relocating %s: origin=%lx, align=%d\n",*argv, origin, align);

  m->textrel = origin;
  m->datarel = origin + m->f.seg[0].length;
  if (m->datarel % align != 0) {
    pad[0] = align - (m->datarel % align);
    m->datarel += pad[0];
  } else {
    pad[0] = 0;
  }

  m->bssrel = m->datarel + m->f.seg[1].length;
  if (m->bssrel % align != 0) {
    pad[1] = align - (m->bssrel % align);
    m->bssrel += pad[1];
  } else {
    pad[1] = 0;
  }

  printf("code: %08lx\ndata: %08lx\nbss:  %08lx\n",
	 m->textrel, m->datarel, m->bssrel);

  rdf_relocate(m);

  argv++;

  of = fopen(*argv,"w");
  if (!of) {
    fprintf(stderr,"rdf2ihx: could not open output file %s\n",*argv);
    return(1);
  }

  padding = malloc(align);
  if (!padding) {
    fprintf(stderr,"rdf2ihx: out of memory\n");
    return(1);
  }

  /* write extended segment address record */
  fprintf(of, ":02000002");	/* Record mark, reclen, load offset & rectyp
				   fields for ext. seg. address record */
  segaddr = ((origin >> 16) & 0xffff);	/* segment address */
  fprintf(of, "%04X", (unsigned int)(segaddr & 0xffff));
  checksum = 0x02 +		/* reclen */
    0x0000 +			/* Load Offset */
    0x02 +			/* Rectyp */
    (segaddr & 0xff) +		/* USBA low */
    ((segaddr >> 8) & 0xff);	/* USBA high */
  checksum = ~checksum + 1;	/* two's-complement the checksum */
  fprintf(of, "%02X\n", checksum & 0xff);

  /* See if there's a '_main' symbol in the symbol table */
  if ((s=symtabFind(m->symtab, "_main")) == NULL) {
    printf("No _main symbol found, no start segment address record added\n");
  } else {
    printf("_main symbol found at %04x:%04x\n", s->segment, 
	   (unsigned int)(s->offset & 0xffff));
    /* Create a start segment address record for the _main symbol. */
    segaddr = ((s->segment & 0xffff) << 16) + ((s->offset) & 0xffff);
    fprintf(of, ":04000003");	/* Record mark, reclen, load offset & rectyp
				   fields for start seg. addr. record */
    fprintf(of, "%08lX", segaddr); /* CS/IP field */
    checksum = 0x04 +		/* reclen */
      0x0000 +			/* load offset */
      0x03 +			/* Rectyp */
      (segaddr & 0xff) +	/* low-low byte of segaddr */
      ((segaddr >> 8) & 0xff) +	/* low-high byte of segaddr */
      ((segaddr >> 16) & 0xff) + /* high-low byte of segaddr */
      ((segaddr >> 24) & 0xff);	/* high-high byte of segaddr */
    checksum = ~checksum + 1;	/* two's complement */
    fprintf(of, "%02X\n", checksum & 0xff);
  }

  /* Now it's time to write data records from the code and data segments in.
     This current version doesn't check for segment overflow; proper behavior
     should be to output a segment address record for the code and data
     segments.  Something to do. */
  ofs = 0;
  segbin[0] = m->t;
  segbin[1] = m->d;
  for (segn=0; segn<2; segn++) {
    int mod, adr;

    if (m->f.seg[segn].length == 0)
      continue;
    for (i=0; i+15<m->f.seg[segn].length; i+=16) {
      ofs = write_data_record(of, ofs, 16, &segbin[segn][i]);
    }
    if ((mod=m->f.seg[segn].length & 0x000f) != 0) {
      adr = m->f.seg[segn].length & 0xfff0;
      ofs = write_data_record(of, ofs, mod, &segbin[segn][adr]);
    }
  }
  /* output an end of file record */
  fprintf(of, ":00000001FF\n");

  fclose(of);
  return 0;
}