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/* Copyright (c) 1996-98, Timothy Mann */
/* $Id: load_cmd.c,v 1.4 2008/06/26 04:39:56 mann Exp $ */
/* This software may be copied, modified, and used for any purpose
* without fee, provided that (1) the above copyright notice is
* retained, and (2) modified versions are clearly marked as having
* been modified, with the modifier's name and the date included. */
/* TRS-80 DOS /cmd file loader.
*
* See the LDOS Quarterly, April 1, 1982 (Vol 1, No 4), for documentation
* of the TRS-80 DOS /cmd file format.
*/
#include <stdio.h>
#include <string.h>
#include "load_cmd.h"
int
load_cmd(FILE* f, unsigned char memory[1<<16],
unsigned char* loadmap, int verbosity, FILE* outf,
int isam, char* pds, int* xferaddr, int stopxfer)
{
int lastaddr = -1, lastcount = -1;
int c, a1, a2, a3, v, count, dummy, i;
int pflags1, pflags2;
char pentry[9];
int ientry, iaddr, iseek, ilen;
int status = LOAD_CMD_OK;
unsigned short addr; /* wrap at 2**16 */
if (loadmap) {
memset(loadmap, 0, 1<<16);
}
if (xferaddr) {
*xferaddr = -1;
} else {
xferaddr = &dummy;
}
for (;;) {
c = getc(f); /* get block type code */
if (c != 1 /* not loading bytes into memory */) {
if (verbosity >= VERBOSITY_MAP) {
if (lastaddr != -1) {
fprintf(outf, "loaded 0x%04x - 0x%04x\n",
lastaddr, lastaddr + lastcount - 1);
}
lastaddr = -1;
}
}
if (c == EOF) return status;
count = getc(f);
if (count == EOF) {
if (c == 3) return status;
return LOAD_CMD_EOF;
}
if (count == 0) count = 256;
switch (c) {
case 0: /* skip (used by Model I TRSDOS BOOT/SYS easter egg) */
if (verbosity >= VERBOSITY_MAP) {
fprintf(outf, "skip block, %d bytes\n", count);
}
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
}
break;
case 1: /* load bytes into memory */
a1 = getc(f);
if (a1 == EOF) return LOAD_CMD_EOF;
a2 = getc(f);
if (a2 == EOF) return LOAD_CMD_EOF;
addr = a1 + a2 * 256;
count -= 2;
if (count <= 0) count += 256;
if (verbosity >= VERBOSITY_MAP) {
if (verbosity >= VERBOSITY_DETAILED ||
addr != lastaddr + lastcount) {
if (lastaddr != -1) {
fprintf(outf, "loaded 0x%04x - 0x%04x\n",
lastaddr, lastaddr + lastcount - 1);
}
lastaddr = addr;
lastcount = count;
} else {
lastcount += count;
}
}
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
/* Don't load PDS front end if specific member requested */
if (!(pds && isam == -1)) {
memory[addr] = v;
if (loadmap) loadmap[addr]++;
}
addr++;
}
break;
case 2: /* transfer address and end of file */
if (count != 2) return c;
a1 = getc(f);
if (a1 == EOF) return LOAD_CMD_EOF;
a2 = getc(f);
if (a2 == EOF) return LOAD_CMD_EOF;
*xferaddr = a1 + a2 * 256;
if (verbosity >= VERBOSITY_MAP) {
fprintf(outf, "transfer address = 0x%04x\n", *xferaddr);
}
if (stopxfer) return status;
break;
case 3: /* end of file with no transfer address */
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
}
return status;
case 4: /* end of ISAM/PDS member */
if (verbosity >= VERBOSITY_MAP) {
fprintf(outf, "end of ISAM/PDS member\n");
}
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
}
if (isam != -1) return status;
if (verbosity >= VERBOSITY_MAP) {
fprintf(outf, "seek ptr = 0x%06lx\n", ftell(f));
}
break;
case 5: /* module header */
if (verbosity >= VERBOSITY_TEXT) {
fprintf(outf, "module header = \"");
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
putc(v, outf);
}
fprintf(outf, "\"\n");
} else {
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
}
}
break;
case 6: /* PDS header */
if (verbosity >= VERBOSITY_TEXT) {
fprintf(outf, "PDS header = \"");
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
putc(v, outf);
}
fprintf(outf, "\"\n");
} else {
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
}
}
break;
case 7: /* Patch name header */
if (verbosity >= VERBOSITY_TEXT) {
fprintf(outf, "patch name = \"");
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
putc(v, outf);
}
fprintf(outf, "\"\n");
} else {
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
}
}
break;
case 8: /* ISAM directory entry */
if (status == LOAD_CMD_OK) status = LOAD_CMD_ISAM;
if (count == 6 || count == 9) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
ientry = v;
a1 = getc(f);
if (a1 == EOF) return LOAD_CMD_EOF;
a2 = getc(f);
if (a2 == EOF) return LOAD_CMD_EOF;
iaddr = a1 + a2 * 256;
a1 = getc(f);
if (a1 == EOF) return LOAD_CMD_EOF;
a2 = getc(f);
if (a2 == EOF) return LOAD_CMD_EOF;
a3 = getc(f);
if (a3 == EOF) return LOAD_CMD_EOF;
iseek = (a2 << 16) + (a1 << 8) + a3;
} else {
return c;
}
if (count == 9) {
/* Is this right? */
a1 = getc(f);
if (a1 == EOF) return LOAD_CMD_EOF;
a2 = getc(f);
if (a2 == EOF) return LOAD_CMD_EOF;
a3 = getc(f);
if (a3 == EOF) return LOAD_CMD_EOF;
ilen = (a2 << 16) + (a1 << 8) + a3; /*???*/
} else {
ilen = -1;
}
if (verbosity >= VERBOSITY_MAP) {
fprintf(outf, "ISAM entry 0x%02x, transfer 0x%04x, seek ptr 0x%06x",
ientry, iaddr, iseek);
if (ilen != -1) {
fprintf(outf, ", length 0x%06x\n", ilen);
} else {
fprintf(outf, "\n");
}
}
if (ientry == isam) {
fseek(f, iseek, 0);
*xferaddr = iaddr;
}
break;
case 0x0a: /* end of ISAM directory */
if (verbosity >= VERBOSITY_MAP) {
fprintf(outf, "end of ISAM directory\n");
}
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
}
if (isam != -1) return LOAD_CMD_NOT_FOUND;
break;
case 0x0c: /* PDS directory entry */
status = LOAD_CMD_PDS;
if (count != 11) {
return c;
}
for (i=0; i<8; i++) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
pentry[i] = v;
}
pentry[8] = '\000';
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
ientry = v;
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
pflags1 = v;
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
pflags2 = v;
if (pds && strcmp(pds, pentry) == 0) {
isam = ientry;
}
if (verbosity >= VERBOSITY_MAP) {
fprintf(outf, "PDS entry \"%s\", ISAM 0x%02x, flags 0x%02x 0x%02x\n",
pentry, ientry, pflags1, pflags2);
}
break;
case 0x0e: /* end of PDS directory */
if (verbosity >= VERBOSITY_MAP) {
fprintf(outf, "end of PDS directory\n");
}
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
}
if (pds != NULL && isam == -1) return LOAD_CMD_NOT_FOUND;
break;
case 0x10: /* yanked load block */
a1 = getc(f);
if (a1 == EOF) return LOAD_CMD_EOF;
a2 = getc(f);
if (a2 == EOF) return LOAD_CMD_EOF;
addr = a1 + a2 * 256;
count -= 2;
if (count <= 0) count += 256;
if (verbosity >= VERBOSITY_MAP) {
fprintf(outf, "yanked load block 0x%04x - 0x%04x\n",
addr, addr + count - 1);
}
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
}
break;
case 0x1f: /* copyright block */
if (verbosity >= VERBOSITY_TEXT) {
fprintf(outf, "====copyright block====\n");
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
putc(v, outf);
}
fprintf(outf, "\n=======================\n");
} else {
while (count-- > 0) {
v = getc(f);
if (v == EOF) return LOAD_CMD_EOF;
}
}
break;
default:
return c;
}
}
return status;
}
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