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/*
xa65 - 6502 cross assembler and utility suite
reloc65 - relocates 'o65' files
Copyright (C) 1997 André Fachat (a.fachat@physik.tu-chemnitz.de)
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
Modified by Dag Lem <resid@nimrod.no>
Relocate and extract text segment from memory buffer instead of file.
For use with VICE VSID.
*/
#include <stdio.h>
#include <string.h>
#define BUF (9*2+8) /* 16 bit header */
typedef struct {
char *fname;
size_t fsize;
unsigned char *buf;
int tbase, tlen, dbase, dlen, bbase, blen, zbase, zlen;
int tdiff, ddiff, bdiff, zdiff;
unsigned char *segt;
unsigned char *segd;
unsigned char *utab;
unsigned char *rttab;
unsigned char *rdtab;
unsigned char *extab;
} file65;
int read_options(unsigned char *f);
int read_undef(unsigned char *f);
unsigned char *reloc_seg(unsigned char *f, int len, unsigned char *rtab, file65 *fp);
unsigned char *reloc_globals(unsigned char *, file65 *fp);
file65 file;
unsigned char cmp[] = { 1, 0, 'o', '6', '5' };
int reloc65(unsigned char** buf, int* fsize, int addr)
{
int mode, hlen;
int tflag=0, dflag=0, bflag=0, zflag=0;
int tbase=0, dbase=0, bbase=0, zbase=0;
int extract = 0;
file.buf = *buf;
file.fsize = *fsize;
tflag= 1;
tbase = addr;
extract = 1;
if (memcmp(file.buf, cmp, 5) != 0) {
return 0;
}
mode=file.buf[7]*256+file.buf[6];
if(mode & 0x2000) {
return 0;
} else if(mode & 0x4000) {
return 0;
}
hlen = BUF+read_options(file.buf+BUF);
file.tbase = file.buf[ 9]*256+file.buf[ 8];
file.tlen = file.buf[11]*256+file.buf[10];
file.tdiff = tflag? tbase - file.tbase : 0;
file.dbase = file.buf[13]*256+file.buf[12];
file.dlen = file.buf[15]*256+file.buf[14];
file.ddiff = dflag? dbase - file.dbase : 0;
file.bbase = file.buf[17]*256+file.buf[16];
file.blen = file.buf[19]*256+file.buf[18];
file.bdiff = bflag? bbase - file.bbase : 0;
file.zbase = file.buf[21]*256+file.buf[20];
file.zlen = file.buf[23]*256+file.buf[21];
file.zdiff = zflag? zbase - file.zbase : 0;
file.segt = file.buf + hlen;
file.segd = file.segt + file.tlen;
file.utab = file.segd + file.dlen;
file.rttab = file.utab + read_undef(file.utab);
file.rdtab = reloc_seg(file.segt, file.tlen, file.rttab, &file);
file.extab = reloc_seg(file.segd, file.dlen, file.rdtab, &file);
reloc_globals(file.extab, &file);
if(tflag) {
file.buf[ 9]= (tbase>>8)&255;
file.buf[ 8]= tbase & 255;
}
if(dflag) {
file.buf[13]= (dbase>>8)&255;
file.buf[12]= dbase & 255;
}
if(bflag) {
file.buf[17]= (bbase>>8)&255;
file.buf[16]= bbase & 255;
}
if(zflag) {
file.buf[21]= (zbase>>8)&255;
file.buf[20]= zbase & 255;
}
switch(extract) {
case 0: /* whole file */
return 1;
case 1: /* text segment */
*buf = file.segt;
*fsize = file.tlen;
return 1;
case 2:
*buf = file.segd;
*fsize = file.dlen;
return 1;
default:
return 0;
}
}
int read_options(unsigned char *buf) {
int c, l=0;
c=buf[0];
while(c && c!=EOF) {
c&=255;
l+=c;
c=buf[l];
}
return ++l;
}
int read_undef(unsigned char *buf) {
int n, l = 2;
n = buf[0] + 256*buf[1];
while(n){
n--;
while(!buf[l++]);
}
return l;
}
#define reldiff(s) (((s)==2)?fp->tdiff:(((s)==3)?fp->ddiff:(((s)==4)?fp->bdiff:(((s)==5)?fp->zdiff:0))))
unsigned char *reloc_seg(unsigned char *buf, int len, unsigned char *rtab, file65 *fp) {
int adr = -1;
int type, seg, old, new;
/*printf("tdiff=%04x, ddiff=%04x, bdiff=%04x, zdiff=%04x\n",
fp->tdiff, fp->ddiff, fp->bdiff, fp->zdiff);*/
while(*rtab) {
if((*rtab & 255) == 255) {
adr += 254;
rtab++;
} else {
adr += *rtab & 255;
rtab++;
type = *rtab & 0xe0;
seg = *rtab & 0x07;
/*printf("reloc entry @ rtab=%p (offset=%d), adr=%04x, type=%02x, seg=%d\n",rtab-1, *(rtab-1), adr, type, seg);*/
rtab++;
switch(type) {
case 0x80:
old = buf[adr] + 256*buf[adr+1];
new = old + reldiff(seg);
buf[adr] = new & 255;
buf[adr+1] = (new>>8)&255;
break;
case 0x40:
old = buf[adr]*256 + *rtab;
new = old + reldiff(seg);
buf[adr] = (new>>8)&255;
*rtab = new & 255;
rtab++;
break;
case 0x20:
old = buf[adr];
new = old + reldiff(seg);
buf[adr] = new & 255;
break;
}
if(seg==0) rtab+=2;
}
}
if(adr > len) {
/*
fprintf(stderr,"reloc65: %s: Warning: relocation table entries past segment end!\n",
fp->fname);
*/
}
return ++rtab;
}
unsigned char *reloc_globals(unsigned char *buf, file65 *fp) {
int n, old, new, seg;
n = buf[0] + 256*buf[1];
buf +=2;
while(n) {
/*printf("relocating %s, ", buf);*/
while(*(buf++));
seg = *buf;
old = buf[1] + 256*buf[2];
new = old + reldiff(seg);
/*printf("old=%04x, seg=%d, rel=%04x, new=%04x\n", old, seg, reldiff(seg), new);*/
buf[1] = new & 255;
buf[2] = (new>>8) & 255;
buf +=3;
n--;
}
return buf;
}
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