BR 2413265: don't pessimize displacements
[nasm/nasm.git] / ndisasm.c
blob766119b999bad6a3b55f768952471761367e345b
1 /* ndisasm.c the Netwide Disassembler main module
3 * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
4 * Julian Hall. All rights reserved. The software is
5 * redistributable under the license given in the file "LICENSE"
6 * distributed in the NASM archive.
7 */
9 #include "compiler.h"
11 #include <stdio.h>
12 #include <stdarg.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include <ctype.h>
16 #include <errno.h>
17 #include <inttypes.h>
19 #include "insns.h"
20 #include "nasm.h"
21 #include "nasmlib.h"
22 #include "sync.h"
23 #include "disasm.h"
25 #define BPL 8 /* bytes per line of hex dump */
27 static const char *help =
28 "usage: ndisasm [-a] [-i] [-h] [-r] [-u] [-b bits] [-o origin] [-s sync...]\n"
29 " [-e bytes] [-k start,bytes] [-p vendor] file\n"
30 " -a or -i activates auto (intelligent) sync\n"
31 " -u same as -b 32\n"
32 " -b 16, -b 32 or -b 64 sets the processor mode\n"
33 " -h displays this text\n"
34 " -r or -v displays the version number\n"
35 " -e skips <bytes> bytes of header\n"
36 " -k avoids disassembling <bytes> bytes from position <start>\n"
37 " -p selects the preferred vendor instruction set (intel, amd, cyrix, idt)\n";
39 static void output_ins(uint32_t, uint8_t *, int, char *);
40 static void skip(uint32_t dist, FILE * fp);
42 static void ndisasm_error(int severity, const char *fmt, ...)
44 va_list va;
46 va_start(va, fmt);
47 vfprintf(stderr, fmt, va);
49 if (severity & ERR_FATAL)
50 exit(1);
53 int main(int argc, char **argv)
55 char buffer[INSN_MAX * 2], *p, *ep, *q;
56 char outbuf[256];
57 char *pname = *argv;
58 char *filename = NULL;
59 uint32_t nextsync, synclen, initskip = 0L;
60 int lenread;
61 int32_t lendis;
62 bool autosync = false;
63 int bits = 16, b;
64 bool eof = false;
65 uint32_t prefer = 0;
66 bool rn_error;
67 int32_t offset;
68 FILE *fp;
70 tolower_init();
71 nasm_set_malloc_error(ndisasm_error);
73 offset = 0;
74 init_sync();
76 while (--argc) {
77 char *v, *vv, *p = *++argv;
78 if (*p == '-' && p[1]) {
79 p++;
80 while (*p)
81 switch (nasm_tolower(*p)) {
82 case 'a': /* auto or intelligent sync */
83 case 'i':
84 autosync = true;
85 p++;
86 break;
87 case 'h':
88 fprintf(stderr, help);
89 return 0;
90 case 'r':
91 case 'v':
92 fprintf(stderr,
93 "NDISASM version %s compiled on %s\n",
94 nasm_version, nasm_date);
95 return 0;
96 case 'u': /* -u for -b 32, -uu for -b 64 */
97 if (bits < 64)
98 bits <<= 1;
99 p++;
100 break;
101 case 'b': /* bits */
102 v = p[1] ? p + 1 : --argc ? *++argv : NULL;
103 if (!v) {
104 fprintf(stderr, "%s: `-b' requires an argument\n",
105 pname);
106 return 1;
108 b = strtoul(v, &ep, 10);
109 if (*ep || !(bits == 16 || bits == 32 || bits == 64)) {
110 fprintf(stderr, "%s: argument to `-b' should"
111 " be 16, 32 or 64\n", pname);
112 } else {
113 bits = b;
115 p = ""; /* force to next argument */
116 break;
117 case 'o': /* origin */
118 v = p[1] ? p + 1 : --argc ? *++argv : NULL;
119 if (!v) {
120 fprintf(stderr, "%s: `-o' requires an argument\n",
121 pname);
122 return 1;
124 offset = readnum(v, &rn_error);
125 if (rn_error) {
126 fprintf(stderr,
127 "%s: `-o' requires a numeric argument\n",
128 pname);
129 return 1;
131 p = ""; /* force to next argument */
132 break;
133 case 's': /* sync point */
134 v = p[1] ? p + 1 : --argc ? *++argv : NULL;
135 if (!v) {
136 fprintf(stderr, "%s: `-s' requires an argument\n",
137 pname);
138 return 1;
140 add_sync(readnum(v, &rn_error), 0L);
141 if (rn_error) {
142 fprintf(stderr,
143 "%s: `-s' requires a numeric argument\n",
144 pname);
145 return 1;
147 p = ""; /* force to next argument */
148 break;
149 case 'e': /* skip a header */
150 v = p[1] ? p + 1 : --argc ? *++argv : NULL;
151 if (!v) {
152 fprintf(stderr, "%s: `-e' requires an argument\n",
153 pname);
154 return 1;
156 initskip = readnum(v, &rn_error);
157 if (rn_error) {
158 fprintf(stderr,
159 "%s: `-e' requires a numeric argument\n",
160 pname);
161 return 1;
163 p = ""; /* force to next argument */
164 break;
165 case 'k': /* skip a region */
166 v = p[1] ? p + 1 : --argc ? *++argv : NULL;
167 if (!v) {
168 fprintf(stderr, "%s: `-k' requires an argument\n",
169 pname);
170 return 1;
172 vv = strchr(v, ',');
173 if (!vv) {
174 fprintf(stderr,
175 "%s: `-k' requires two numbers separated"
176 " by a comma\n", pname);
177 return 1;
179 *vv++ = '\0';
180 nextsync = readnum(v, &rn_error);
181 if (rn_error) {
182 fprintf(stderr,
183 "%s: `-k' requires numeric arguments\n",
184 pname);
185 return 1;
187 synclen = readnum(vv, &rn_error);
188 if (rn_error) {
189 fprintf(stderr,
190 "%s: `-k' requires numeric arguments\n",
191 pname);
192 return 1;
194 add_sync(nextsync, synclen);
195 p = ""; /* force to next argument */
196 break;
197 case 'p': /* preferred vendor */
198 v = p[1] ? p + 1 : --argc ? *++argv : NULL;
199 if (!v) {
200 fprintf(stderr, "%s: `-p' requires an argument\n",
201 pname);
202 return 1;
204 if (!strcmp(v, "intel")) {
205 prefer = 0; /* Default */
206 } else if (!strcmp(v, "amd")) {
207 prefer = IF_AMD | IF_3DNOW;
208 } else if (!strcmp(v, "cyrix")) {
209 prefer = IF_CYRIX | IF_3DNOW;
210 } else if (!strcmp(v, "idt") || !strcmp(v, "centaur")
211 || !strcmp(v, "winchip")) {
212 prefer = IF_3DNOW;
213 } else {
214 fprintf(stderr,
215 "%s: unknown vendor `%s' specified with `-p'\n",
216 pname, v);
217 return 1;
219 p = ""; /* force to next argument */
220 break;
221 default: /*bf */
222 fprintf(stderr, "%s: unrecognised option `-%c'\n",
223 pname, *p);
224 return 1;
226 } else if (!filename) {
227 filename = p;
228 } else {
229 fprintf(stderr, "%s: more than one filename specified\n",
230 pname);
231 return 1;
235 if (!filename) {
236 fprintf(stderr, help, pname);
237 return 0;
240 if (strcmp(filename, "-")) {
241 fp = fopen(filename, "rb");
242 if (!fp) {
243 fprintf(stderr, "%s: unable to open `%s': %s\n",
244 pname, filename, strerror(errno));
245 return 1;
247 } else
248 fp = stdin;
250 if (initskip > 0)
251 skip(initskip, fp);
254 * This main loop is really horrible, and wants rewriting with
255 * an axe. It'll stay the way it is for a while though, until I
256 * find the energy...
259 p = q = buffer;
260 nextsync = next_sync(offset, &synclen);
261 do {
262 uint32_t to_read = buffer + sizeof(buffer) - p;
263 if ((nextsync || synclen) &&
264 to_read > nextsync - offset - (p - q))
265 to_read = nextsync - offset - (p - q);
266 if (to_read) {
267 lenread = fread(p, 1, to_read, fp);
268 if (lenread == 0)
269 eof = true; /* help along systems with bad feof */
270 } else
271 lenread = 0;
272 p += lenread;
273 if ((nextsync || synclen) &&
274 (uint32_t)offset == nextsync) {
275 if (synclen) {
276 fprintf(stdout, "%08"PRIX32" skipping 0x%"PRIX32" bytes\n", offset, synclen);
277 offset += synclen;
278 skip(synclen, fp);
280 p = q = buffer;
281 nextsync = next_sync(offset, &synclen);
283 while (p > q && (p - q >= INSN_MAX || lenread == 0)) {
284 lendis =
285 disasm((uint8_t *) q, outbuf, sizeof(outbuf), bits, offset, autosync,
286 prefer);
287 if (!lendis || lendis > (p - q)
288 || ((nextsync || synclen) &&
289 (uint32_t)lendis > nextsync - offset))
290 lendis = eatbyte((uint8_t *) q, outbuf, sizeof(outbuf));
291 output_ins(offset, (uint8_t *) q, lendis, outbuf);
292 q += lendis;
293 offset += lendis;
295 if (q >= buffer + INSN_MAX) {
296 uint8_t *r = (uint8_t *) buffer, *s = (uint8_t *) q;
297 int count = p - q;
298 while (count--)
299 *r++ = *s++;
300 p -= (q - buffer);
301 q = buffer;
303 } while (lenread > 0 || !(eof || feof(fp)));
305 if (fp != stdin)
306 fclose(fp);
308 return 0;
311 static void output_ins(uint32_t offset, uint8_t *data,
312 int datalen, char *insn)
314 int bytes;
315 fprintf(stdout, "%08"PRIX32" ", offset);
317 bytes = 0;
318 while (datalen > 0 && bytes < BPL) {
319 fprintf(stdout, "%02X", *data++);
320 bytes++;
321 datalen--;
324 fprintf(stdout, "%*s%s\n", (BPL + 1 - bytes) * 2, "", insn);
326 while (datalen > 0) {
327 fprintf(stdout, " -");
328 bytes = 0;
329 while (datalen > 0 && bytes < BPL) {
330 fprintf(stdout, "%02X", *data++);
331 bytes++;
332 datalen--;
334 fprintf(stdout, "\n");
339 * Skip a certain amount of data in a file, either by seeking if
340 * possible, or if that fails then by reading and discarding.
342 static void skip(uint32_t dist, FILE * fp)
344 char buffer[256]; /* should fit on most stacks :-) */
347 * Got to be careful with fseek: at least one fseek I've tried
348 * doesn't approve of SEEK_CUR. So I'll use SEEK_SET and
349 * ftell... horrible but apparently necessary.
351 if (fseek(fp, dist + ftell(fp), SEEK_SET)) {
352 while (dist > 0) {
353 uint32_t len = (dist < sizeof(buffer) ?
354 dist : sizeof(buffer));
355 if (fread(buffer, 1, len, fp) < len) {
356 perror("fread");
357 exit(1);
359 dist -= len;