/*
 * This ad hoc utility is used as part of building RAM-loadable
 * firmware images for targets with large RAM.  It reads the ramimage.m0
 * S-record file produced by TI's hex470 post-linker and re-emits it
 * in another SREC form that is suitable for feeding to fc-xram.
 */

#include <sys/types.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>

char *infname;
FILE *inf, *outf;
char srecbuf[80];
u_char srecbin[40], srecout[40];
int lineno;

decode_hex_byte(s)
	char *s;
{
	register int u, l;

	if (!isxdigit(s[0]) || !isxdigit(s[1]))
		return(-1);
	if (isdigit(s[0]))
		u = s[0] - '0';
	else if (isupper(s[0]))
		u = s[0] - 'A' + 10;
	else
		u = s[0] - 'a' + 10;
	if (isdigit(s[1]))
		l = s[1] - '0';
	else if (isupper(s[1]))
		l = s[1] - 'A' + 10;
	else
		l = s[1] - 'a' + 10;
	return((u << 4) | l);
}

srec2bin()
{
	register int i, l, b;

	l = decode_hex_byte(srecbuf + 2);
	if (l < 1) {
		fprintf(stderr, "%s line %d: S-record length octet is bad\n",
			infname, lineno);
		exit(1);
	}
	srecbin[0] = l;
	if (l > 35) {
		fprintf(stderr,
			"%s line %d: S-record is longer than expected\n",
			infname, lineno);
		exit(1);
	}
	for (i = 1; i <= l; i++) {
		b = decode_hex_byte(srecbuf + i*2 + 2);
		if (b < 0) {
			fprintf(stderr, "%s line %d: hex decode error\n",
				infname, lineno);
			exit(1);
		}
		srecbin[i] = b;
	}
	return(0);
}

srec_cksum()
{
	u_char accum;
	register int i, len;

	len = srecbin[0] + 1;
	accum = 0;
	for (i = 0; i < len; i++)
		accum += srecbin[i];
	if (accum != 0xFF) {
		fprintf(stderr, "%s line %d: bad checksum\n", infname, lineno);
		exit(1);
	}
	return(0);
}

emit_output_srec(type, buf)
	u_char *buf;
{
	int i;
	u_char accum = 0;

	putc('S', outf);
	putc(type, outf);
	for (i = 0; i < buf[0]; i++) {
		fprintf(outf, "%02X", buf[i]);
		accum += buf[i];
	}
	fprintf(outf, "%02X\n", ~accum & 0xFF);
	return 0;
}

transform_s3()
{
	int datalen;
	u_char *sp, *dp;
	int i;

	if (srecbin[0] < 6) {
		fprintf(stderr,
			"%s line %d: S3 record is too short\n",
			infname, lineno);
		exit(1);
	}
	datalen = srecbin[0] - 5;
	if (datalen & 1) {
		fprintf(stderr, "%s line %d: odd data length\n",
			infname, lineno);
		exit(1);
	}
	sp = srecbin;
	dp = srecout;
	for (i = 0; i < 5; i++)
		*dp++ = *sp++;
	for (i = 0; i < datalen; i += 2) {
		dp[0] = sp[1];
		dp[1] = sp[0];
		sp += 2;
		dp += 2;
	}
	return 0;
}

generate_vectors_record()
{
	u_char *dp;
	u_long addr;
	int i;

	srecout[0] = 28 + 5;
	srecout[1] = 0x00;
	srecout[2] = 0x80;
	srecout[3] = 0x00;
	srecout[4] = 0x00;
	dp = srecout + 5;
	for (i = 0; i < 7; i++) {
		addr = 0x01004000 + i * 4;
		*dp++ = addr;
		*dp++ = addr >> 8;
		*dp++ = addr >> 16;
		*dp++ = addr >> 24;
	}
	emit_output_srec('3', srecout);
	return 0;
}

generate_jump_record()
{
	srecout[0] = 5;
	srecout[1] = 0x01;
	srecout[2] = 0x00;
	srecout[3] = 0x40;
	srecout[4] = 0x58;
	emit_output_srec('7', srecout);
	return 0;
}

main(argc, argv)
	char **argv;
{
	if (argc < 2 || argc > 3) {
		fprintf(stderr, "usage: %s input.m0 [output.srec]\n", argv[0]);
		exit(1);
	}
	infname = argv[1];
	inf = fopen(infname, "r");
	if (!inf) {
		perror(infname);
		exit(1);
	}
	if (argc > 2) {
		outf = fopen(argv[2], "w");
		if (!outf) {
			perror(argv[2]);
			exit(1);
		}
	} else
		outf = stdout;
	for (lineno = 1; ; lineno++) {
		if (!fgets(srecbuf, sizeof srecbuf, inf)) {
			fprintf(stderr, "%s: premature EOF\n", infname);
			exit(1);
		}
		if (srecbuf[0] != 'S') {
			fprintf(stderr, "%s line %d: not an S-record\n",
				infname, lineno);
			exit(1);
		}
		srec2bin();
		srec_cksum();
		switch (srecbuf[1]) {
		case '0':
			emit_output_srec('0', srecbin);
			continue;
		case '3':
			transform_s3();
			emit_output_srec('3', srecout);
			continue;
		case '7':
			break;
		default:
			fprintf(stderr, "%s line %d: unexpected S%c record\n",
				infname, lineno, srecbuf[1]);
			exit(1);
		}
		break;
	}
	generate_vectors_record();
	generate_jump_record();
	exit(0);
}