1 /*
2 xa65 - 6502 cross assembler and utility suite
3 reloc65 - relocates 'o65' files
4 Copyright (C) 1997 Andr� Fachat (a.fachat@physik.tu-chemnitz.de)
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21 /*
22 Modified by Dag Lem <resid@nimrod.no>
23 Relocate and extract text segment from memory buffer instead of file.
24 For use with VICE VSID.
25 */
26
27 #include <stdio.h>
28 #include <string.h>
29
30 #define BUF (9*2+8) /* 16 bit header */
31
32 typedef struct {
33 char *fname;
34 size_t fsize;
35 unsigned char *buf;
36 int tbase, tlen, dbase, dlen, bbase, blen, zbase, zlen;
37 int tdiff, ddiff, bdiff, zdiff;
38 unsigned char *segt;
39 unsigned char *segd;
40 unsigned char *utab;
41 unsigned char *rttab;
42 unsigned char *rdtab;
43 unsigned char *extab;
44 } file65;
45
46
47 int read_options(unsigned char *f);
48 int read_undef(unsigned char *f);
49 unsigned char *reloc_seg(unsigned char *f, int len, unsigned char *rtab, file65 *fp);
50 unsigned char *reloc_globals(unsigned char *, file65 *fp);
51
52 file65 file;
53 unsigned char cmp[] = { 1, 0, 'o', '6', '5' };
54
reloc65(unsigned char ** buf,int * fsize,int addr)55 int reloc65(unsigned char** buf, int* fsize, int addr)
56 {
57 int mode, hlen;
58
59 int tflag=0, dflag=0, bflag=0, zflag=0;
60 int tbase=0, dbase=0, bbase=0, zbase=0;
61 int extract = 0;
62
63 file.buf = *buf;
64 file.fsize = *fsize;
65 tflag= 1;
66 tbase = addr;
67 extract = 1;
68
69 if (memcmp(file.buf, cmp, 5) != 0) {
70 return 0;
71 }
72
73 mode=file.buf[7]*256+file.buf[6];
74 if(mode & 0x2000) {
75 return 0;
76 } else if(mode & 0x4000) {
77 return 0;
78 }
79
80 hlen = BUF+read_options(file.buf+BUF);
81
82 file.tbase = file.buf[ 9]*256+file.buf[ 8];
83 file.tlen = file.buf[11]*256+file.buf[10];
84 file.tdiff = tflag? tbase - file.tbase : 0;
85 file.dbase = file.buf[13]*256+file.buf[12];
86 file.dlen = file.buf[15]*256+file.buf[14];
87 file.ddiff = dflag? dbase - file.dbase : 0;
88 file.bbase = file.buf[17]*256+file.buf[16];
89 file.blen = file.buf[19]*256+file.buf[18];
90 file.bdiff = bflag? bbase - file.bbase : 0;
91 file.zbase = file.buf[21]*256+file.buf[20];
92 file.zlen = file.buf[23]*256+file.buf[21];
93 file.zdiff = zflag? zbase - file.zbase : 0;
94
95 file.segt = file.buf + hlen;
96 file.segd = file.segt + file.tlen;
97 file.utab = file.segd + file.dlen;
98
99 file.rttab = file.utab + read_undef(file.utab);
100
101 file.rdtab = reloc_seg(file.segt, file.tlen, file.rttab, &file);
102 file.extab = reloc_seg(file.segd, file.dlen, file.rdtab, &file);
103
104 reloc_globals(file.extab, &file);
105
106 if(tflag) {
107 file.buf[ 9]= (tbase>>8)&255;
108 file.buf[ 8]= tbase & 255;
109 }
110 if(dflag) {
111 file.buf[13]= (dbase>>8)&255;
112 file.buf[12]= dbase & 255;
113 }
114 if(bflag) {
115 file.buf[17]= (bbase>>8)&255;
116 file.buf[16]= bbase & 255;
117 }
118 if(zflag) {
119 file.buf[21]= (zbase>>8)&255;
120 file.buf[20]= zbase & 255;
121 }
122
123 switch(extract) {
124 case 0: /* whole file */
125 return 1;
126 case 1: /* text segment */
127 *buf = file.segt;
128 *fsize = file.tlen;
129 return 1;
130 case 2:
131 *buf = file.segd;
132 *fsize = file.dlen;
133 return 1;
134 default:
135 return 0;
136 }
137 }
138
139
read_options(unsigned char * buf)140 int read_options(unsigned char *buf) {
141 int c, l=0;
142
143 c=buf[0];
144 while(c && c!=EOF) {
145 c&=255;
146 l+=c;
147 c=buf[l];
148 }
149 return ++l;
150 }
151
read_undef(unsigned char * buf)152 int read_undef(unsigned char *buf) {
153 int n, l = 2;
154
155 n = buf[0] + 256*buf[1];
156 while(n){
157 n--;
158 while(!buf[l++]);
159 }
160 return l;
161 }
162
163 #define reldiff(s) (((s)==2)?fp->tdiff:(((s)==3)?fp->ddiff:(((s)==4)?fp->bdiff:(((s)==5)?fp->zdiff:0))))
164
reloc_seg(unsigned char * buf,int len,unsigned char * rtab,file65 * fp)165 unsigned char *reloc_seg(unsigned char *buf, int len, unsigned char *rtab, file65 *fp) {
166 int adr = -1;
167 int type, seg, old, new;
168 /*printf("tdiff=%04x, ddiff=%04x, bdiff=%04x, zdiff=%04x\n",
169 fp->tdiff, fp->ddiff, fp->bdiff, fp->zdiff);*/
170 while(*rtab) {
171 if((*rtab & 255) == 255) {
172 adr += 254;
173 rtab++;
174 } else {
175 adr += *rtab & 255;
176 rtab++;
177 type = *rtab & 0xe0;
178 seg = *rtab & 0x07;
179 /*printf("reloc entry @ rtab=%p (offset=%d), adr=%04x, type=%02x, seg=%d\n",rtab-1, *(rtab-1), adr, type, seg);*/
180 rtab++;
181 switch(type) {
182 case 0x80:
183 old = buf[adr] + 256*buf[adr+1];
184 new = old + reldiff(seg);
185 buf[adr] = new & 255;
186 buf[adr+1] = (new>>8)&255;
187 break;
188 case 0x40:
189 old = buf[adr]*256 + *rtab;
190 new = old + reldiff(seg);
191 buf[adr] = (new>>8)&255;
192 *rtab = new & 255;
193 rtab++;
194 break;
195 case 0x20:
196 old = buf[adr];
197 new = old + reldiff(seg);
198 buf[adr] = new & 255;
199 break;
200 }
201 if(seg==0) rtab+=2;
202 }
203 }
204 if(adr > len) {
205 /*
206 fprintf(stderr,"reloc65: %s: Warning: relocation table entries past segment end!\n",
207 fp->fname);
208 */
209 }
210 return ++rtab;
211 }
212
reloc_globals(unsigned char * buf,file65 * fp)213 unsigned char *reloc_globals(unsigned char *buf, file65 *fp) {
214 int n, old, new, seg;
215
216 n = buf[0] + 256*buf[1];
217 buf +=2;
218
219 while(n) {
220 /*printf("relocating %s, ", buf);*/
221 while(*(buf++));
222 seg = *buf;
223 old = buf[1] + 256*buf[2];
224 new = old + reldiff(seg);
225 /*printf("old=%04x, seg=%d, rel=%04x, new=%04x\n", old, seg, reldiff(seg), new);*/
226 buf[1] = new & 255;
227 buf[2] = (new>>8) & 255;
228 buf +=3;
229 n--;
230 }
231 return buf;
232 }
233