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/* SPDX-License-Identifier: BSD-2-Clause */
/* Copyright 1996-2025 The NASM Authors - All Rights Reserved */
/*
* ndisasm.c the Netwide Disassembler main module
*/
#include "compiler.h"
#include "nctype.h"
#include <errno.h>
#include "insns.h"
#include "nasm.h"
#include "nasmlib.h"
#include "error.h"
#include "ver.h"
#include "sync.h"
#include "disasm.h"
static int bpl = 8; /* bytes per line of hex dump */
static const char *help =
"usage: ndisasm [-aihlruvw] [-b bits] [-o origin] [-s sync...]\n"
" [-e bytes] [-k start,bytes] [-p vendor] file\n"
" -a or -i activates auto (intelligent) sync\n"
" -b 16, -b 32 or -b 64 sets the processor mode\n"
" -u same as -b 32\n"
" -l same as -b 64\n"
" -w wide output (avoids continuation lines)\n"
" -h displays this text\n"
" -r or -v displays the version number\n"
" -e skips <bytes> bytes of header\n"
" -k avoids disassembling <bytes> bytes from position <start>\n"
" -p selects the preferred vendor instruction set (intel, amd, cyrix, idt)\n";
static void output_ins(uint64_t, const uint8_t *, int, const char *);
static void skip(uint32_t dist, FILE * fp);
void nasm_verror(errflags severity, const char *fmt, va_list val)
{
severity &= ERR_MASK;
vfprintf(stderr, fmt, val);
if (severity >= ERR_FATAL)
exit(severity - ERR_FATAL + 1);
}
fatal_func nasm_verror_critical(errflags severity, const char *fmt, va_list val)
{
nasm_verror(severity, fmt, val);
abort();
}
errflags errflags_never = 0;
int main(int argc, char **argv)
{
uint8_t buffer[INSN_MAX * 2], *p;
const uint8_t *q;
char outbuf[256];
char *pname = *argv;
char *filename = NULL;
uint32_t nextsync, synclen, initskip = 0L;
int lenread;
int32_t lendis;
bool autosync = false;
int bits = 16, b;
bool eof = false;
iflag_t prefer;
bool rn_error;
int64_t offset;
FILE *fp;
nasm_ctype_init();
iflag_clear_all(&prefer);
offset = 0;
init_sync();
while (--argc) {
char *v, *vv, *p = *++argv;
if (*p == '-' && p[1]) {
p++;
while (*p)
switch (nasm_tolower(*p)) {
case 'a': /* auto or intelligent sync */
case 'i':
autosync = true;
p++;
break;
case 'h':
fputs(help, stderr);
return 0;
case 'r':
case 'v':
fprintf(stderr,
"NDISASM version %s\n",
nasm_version);
return 0;
case 'u': /* -u for -b 32, -uu for -b 64 */
if (bits < 64)
bits <<= 1;
p++;
break;
case 'l':
bits = 64;
p++;
break;
case 'w':
bpl = 16;
p++;
break;
case 'b': /* bits */
v = p[1] ? p + 1 : --argc ? *++argv : NULL;
if (!v) {
fprintf(stderr, "%s: `-b' requires an argument\n",
pname);
return 1;
}
b = readnum(v, &rn_error);
if (rn_error ||
!(bits == 16 || bits == 32 || bits == 64)) {
fprintf(stderr, "%s: argument to `-b' should"
" be 16, 32 or 64\n", pname);
} else {
bits = b;
}
p = ""; /* force to next argument */
break;
case 'o': /* origin */
v = p[1] ? p + 1 : --argc ? *++argv : NULL;
if (!v) {
fprintf(stderr, "%s: `-o' requires an argument\n",
pname);
return 1;
}
offset = readnum(v, &rn_error);
if (rn_error) {
fprintf(stderr,
"%s: `-o' requires a numeric argument\n",
pname);
return 1;
}
p = ""; /* force to next argument */
break;
case 's': /* sync point */
v = p[1] ? p + 1 : --argc ? *++argv : NULL;
if (!v) {
fprintf(stderr, "%s: `-s' requires an argument\n",
pname);
return 1;
}
add_sync(readnum(v, &rn_error), 0L);
if (rn_error) {
fprintf(stderr,
"%s: `-s' requires a numeric argument\n",
pname);
return 1;
}
p = ""; /* force to next argument */
break;
case 'e': /* skip a header */
v = p[1] ? p + 1 : --argc ? *++argv : NULL;
if (!v) {
fprintf(stderr, "%s: `-e' requires an argument\n",
pname);
return 1;
}
initskip = readnum(v, &rn_error);
if (rn_error) {
fprintf(stderr,
"%s: `-e' requires a numeric argument\n",
pname);
return 1;
}
p = ""; /* force to next argument */
break;
case 'k': /* skip a region */
v = p[1] ? p + 1 : --argc ? *++argv : NULL;
if (!v) {
fprintf(stderr, "%s: `-k' requires an argument\n",
pname);
return 1;
}
vv = strchr(v, ',');
if (!vv) {
fprintf(stderr,
"%s: `-k' requires two numbers separated"
" by a comma\n", pname);
return 1;
}
*vv++ = '\0';
nextsync = readnum(v, &rn_error);
if (rn_error) {
fprintf(stderr,
"%s: `-k' requires numeric arguments\n",
pname);
return 1;
}
synclen = readnum(vv, &rn_error);
if (rn_error) {
fprintf(stderr,
"%s: `-k' requires numeric arguments\n",
pname);
return 1;
}
add_sync(nextsync, synclen);
p = ""; /* force to next argument */
break;
case 'p': /* preferred vendor */
v = p[1] ? p + 1 : --argc ? *++argv : NULL;
if (!v) {
fprintf(stderr, "%s: `-p' requires an argument\n",
pname);
return 1;
}
if (!strcmp(v, "intel")) {
iflag_clear_all(&prefer); /* default */
} else if (!strcmp(v, "amd")) {
iflag_clear_all(&prefer);
iflag_set(&prefer, IF_AMD);
iflag_set(&prefer, IF_3DNOW);
} else if (!strcmp(v, "cyrix")) {
iflag_clear_all(&prefer);
iflag_set(&prefer, IF_CYRIX);
iflag_set(&prefer, IF_3DNOW);
} else if (!strcmp(v, "idt") ||
!strcmp(v, "centaur") ||
!strcmp(v, "winchip")) {
iflag_clear_all(&prefer);
iflag_set(&prefer, IF_3DNOW);
} else {
fprintf(stderr,
"%s: unknown vendor `%s' specified with `-p'\n",
pname, v);
return 1;
}
p = ""; /* force to next argument */
break;
default: /*bf */
fprintf(stderr, "%s: unrecognised option `-%c'\n",
pname, *p);
return 1;
}
} else if (!filename) {
filename = p;
} else {
fprintf(stderr, "%s: more than one filename specified\n",
pname);
return 1;
}
}
if (!filename) {
fprintf(stderr, help, pname);
return 0;
}
if (strcmp(filename, "-")) {
fp = fopen(filename, "rb");
if (!fp) {
fprintf(stderr, "%s: unable to open `%s': %s\n",
pname, filename, strerror(errno));
return 1;
}
} else {
nasm_set_binary_mode(stdin);
fp = stdin;
}
if (initskip > 0)
skip(initskip, fp);
/*
* This main loop is really horrible, and wants rewriting with
* an axe. It'll stay the way it is for a while though, until I
* find the energy...
*/
q = p = buffer;
nextsync = next_sync(offset, &synclen);
do {
int32_t to_read = buffer + sizeof(buffer) - p;
if ((nextsync || synclen) &&
to_read > nextsync - offset - (p - q))
to_read = nextsync - offset - (p - q);
if (to_read) {
lenread = fread(p, 1, to_read, fp);
if (lenread == 0)
eof = true; /* help along systems with bad feof */
} else
lenread = 0;
p += lenread;
if ((nextsync || synclen) &&
(uint32_t)offset == nextsync) {
if (synclen) {
fprintf(stdout, "%08"PRIX64" skipping 0x%"PRIX32" bytes\n",
offset, synclen);
offset += synclen;
skip(synclen, fp);
}
q = p = buffer;
nextsync = next_sync(offset, &synclen);
}
while (p > q && (p - q >= INSN_MAX || lenread == 0)) {
lendis = disasm(q, INSN_MAX, outbuf, sizeof(outbuf),
bits, offset, autosync, &prefer);
if (!lendis || lendis > (p - q)
|| ((nextsync || synclen) &&
(uint32_t)lendis > nextsync - offset))
lendis = eatbyte(*q, outbuf, sizeof(outbuf), bits);
output_ins(offset, q, lendis, outbuf);
q += lendis;
offset += lendis;
}
if (q >= buffer + INSN_MAX) {
int count = p - q;
memmove(buffer, q, count);
p -= (q - buffer);
q = buffer;
}
} while (lenread > 0 || !(eof || feof(fp)));
if (fp != stdin)
fclose(fp);
return 0;
}
static void output_ins(uint64_t offset, const uint8_t *data,
int datalen, const char *insn)
{
int bytes;
fprintf(stdout, "%08"PRIX64" ", offset);
bytes = 0;
while (datalen > 0 && bytes < bpl) {
fprintf(stdout, "%02X", *data++);
bytes++;
datalen--;
}
fprintf(stdout, "%*s%s\n", (bpl + 1 - bytes) * 2, "", insn);
while (datalen > 0) {
fprintf(stdout, " -");
bytes = 0;
while (datalen > 0 && bytes < bpl) {
fprintf(stdout, "%02X", *data++);
bytes++;
datalen--;
}
fprintf(stdout, "\n");
}
}
/*
* Skip a certain amount of data in a file, either by seeking if
* possible, or if that fails then by reading and discarding.
*/
static void skip(uint32_t dist, FILE * fp)
{
char buffer[256]; /* should fit on most stacks :-) */
/*
* Got to be careful with fseek: at least one fseek I've tried
* doesn't approve of SEEK_CUR. So I'll use SEEK_SET and
* ftell... horrible but apparently necessary.
*/
if (fseek(fp, dist + ftell(fp), SEEK_SET)) {
while (dist > 0) {
uint32_t len = (dist < sizeof(buffer) ?
dist : sizeof(buffer));
if (fread(buffer, 1, len, fp) < len) {
perror("fread");
exit(1);
}
dist -= len;
}
}
}
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