1 /* disasm.c where all the _work_ gets done in the Netwide Disassembler
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.
8 * initial version 27/iii/95 by Simon Tatham
26 * Flags that go into the `segment' field of `insn' structures
29 #define SEG_RELATIVE 1
36 #define SEG_SIGNED 128
43 uint8_t osize; /* Operand size */
44 uint8_t asize; /* Address size */
45 uint8_t osp; /* Operand size prefix present */
46 uint8_t asp; /* Address size prefix present */
47 uint8_t rep; /* Rep prefix present */
48 uint8_t seg; /* Segment override prefix present */
49 uint8_t lock; /* Lock prefix present */
50 uint8_t vex[3]; /* VEX prefix present */
51 uint8_t vex_m; /* VEX.M field */
53 uint8_t vex_lp; /* VEX.LP fields */
54 uint32_t rex; /* REX prefix present */
57 #define getu8(x) (*(uint8_t *)(x))
59 /* Littleendian CPU which can handle unaligned references */
60 #define getu16(x) (*(uint16_t *)(x))
61 #define getu32(x) (*(uint32_t *)(x))
62 #define getu64(x) (*(uint64_t *)(x))
64 static uint16_t getu16(uint8_t *data)
66 return (uint16_t)data[0] + ((uint16_t)data[1] << 8);
68 static uint32_t getu32(uint8_t *data)
70 return (uint32_t)getu16(data) + ((uint32_t)getu16(data+2) << 16);
72 static uint64_t getu64(uint8_t *data)
74 return (uint64_t)getu32(data) + ((uint64_t)getu32(data+4) << 32);
78 #define gets8(x) ((int8_t)getu8(x))
79 #define gets16(x) ((int16_t)getu16(x))
80 #define gets32(x) ((int32_t)getu32(x))
81 #define gets64(x) ((int64_t)getu64(x))
83 /* Important: regval must already have been adjusted for rex extensions */
84 static enum reg_enum whichreg(int32_t regflags, int regval, int rex)
86 if (!(regflags & (REGISTER|REGMEM)))
87 return 0; /* Registers not permissible?! */
91 if (!(REG_AL & ~regflags))
93 if (!(REG_AX & ~regflags))
95 if (!(REG_EAX & ~regflags))
97 if (!(REG_RAX & ~regflags))
99 if (!(REG_DL & ~regflags))
101 if (!(REG_DX & ~regflags))
103 if (!(REG_EDX & ~regflags))
105 if (!(REG_RDX & ~regflags))
107 if (!(REG_CL & ~regflags))
109 if (!(REG_CX & ~regflags))
111 if (!(REG_ECX & ~regflags))
113 if (!(REG_RCX & ~regflags))
115 if (!(FPU0 & ~regflags))
117 if (!(REG_CS & ~regflags))
118 return (regval == 1) ? R_CS : 0;
119 if (!(REG_DESS & ~regflags))
120 return (regval == 0 || regval == 2
121 || regval == 3 ? nasm_rd_sreg[regval] : 0);
122 if (!(REG_FSGS & ~regflags))
123 return (regval == 4 || regval == 5 ? nasm_rd_sreg[regval] : 0);
124 if (!(REG_SEG67 & ~regflags))
125 return (regval == 6 || regval == 7 ? nasm_rd_sreg[regval] : 0);
127 /* All the entries below look up regval in an 16-entry array */
128 if (regval < 0 || regval > 15)
131 if (!(REG8 & ~regflags)) {
133 return nasm_rd_reg8_rex[regval];
135 return nasm_rd_reg8[regval];
137 if (!(REG16 & ~regflags))
138 return nasm_rd_reg16[regval];
139 if (!(REG32 & ~regflags))
140 return nasm_rd_reg32[regval];
141 if (!(REG64 & ~regflags))
142 return nasm_rd_reg64[regval];
143 if (!(REG_SREG & ~regflags))
144 return nasm_rd_sreg[regval & 7]; /* Ignore REX */
145 if (!(REG_CREG & ~regflags))
146 return nasm_rd_creg[regval];
147 if (!(REG_DREG & ~regflags))
148 return nasm_rd_dreg[regval];
149 if (!(REG_TREG & ~regflags)) {
151 return 0; /* TR registers are ill-defined with rex */
152 return nasm_rd_treg[regval];
154 if (!(FPUREG & ~regflags))
155 return nasm_rd_fpureg[regval & 7]; /* Ignore REX */
156 if (!(MMXREG & ~regflags))
157 return nasm_rd_mmxreg[regval & 7]; /* Ignore REX */
158 if (!(XMMREG & ~regflags))
159 return nasm_rd_xmmreg[regval];
160 if (!(YMMREG & ~regflags))
161 return nasm_rd_ymmreg[regval];
167 * Process a DREX suffix
169 static uint8_t *do_drex(uint8_t *data, insn *ins)
171 uint8_t drex = *data++;
172 operand *dst = &ins->oprs[ins->drexdst];
174 if ((drex & 8) != ((ins->rex & REX_OC) ? 8 : 0))
175 return NULL; /* OC0 mismatch */
176 ins->rex = (ins->rex & ~7) | (drex & 7);
178 dst->segment = SEG_RMREG;
179 dst->basereg = drex >> 4;
185 * Process an effective address (ModRM) specification.
187 static uint8_t *do_ea(uint8_t *data, int modrm, int asize,
188 int segsize, operand * op, insn *ins)
190 int mod, rm, scale, index, base;
194 mod = (modrm >> 6) & 03;
197 if (mod != 3 && rm == 4 && asize != 16)
200 if (ins->rex & REX_D) {
201 data = do_drex(data, ins);
207 if (mod == 3) { /* pure register version */
208 op->basereg = rm+(rex & REX_B ? 8 : 0);
209 op->segment |= SEG_RMREG;
218 * <mod> specifies the displacement size (none, byte or
219 * word), and <rm> specifies the register combination.
220 * Exception: mod=0,rm=6 does not specify [BP] as one might
221 * expect, but instead specifies [disp16].
223 op->indexreg = op->basereg = -1;
224 op->scale = 1; /* always, in 16 bits */
255 if (rm == 6 && mod == 0) { /* special case */
259 mod = 2; /* fake disp16 */
263 op->segment |= SEG_NODISP;
266 op->segment |= SEG_DISP8;
267 op->offset = (int8_t)*data++;
270 op->segment |= SEG_DISP16;
271 op->offset = *data++;
272 op->offset |= ((unsigned)*data++) << 8;
278 * Once again, <mod> specifies displacement size (this time
279 * none, byte or *dword*), while <rm> specifies the base
280 * register. Again, [EBP] is missing, replaced by a pure
281 * disp32 (this time that's mod=0,rm=*5*) in 32-bit mode,
282 * and RIP-relative addressing in 64-bit mode.
285 * indicates not a single base register, but instead the
286 * presence of a SIB byte...
288 int a64 = asize == 64;
293 op->basereg = nasm_rd_reg64[rm | ((rex & REX_B) ? 8 : 0)];
295 op->basereg = nasm_rd_reg32[rm | ((rex & REX_B) ? 8 : 0)];
297 if (rm == 5 && mod == 0) {
299 op->eaflags |= EAF_REL;
300 op->segment |= SEG_RELATIVE;
301 mod = 2; /* fake disp32 */
305 op->disp_size = asize;
308 mod = 2; /* fake disp32 */
311 if (rm == 4) { /* process SIB */
312 scale = (sib >> 6) & 03;
313 index = (sib >> 3) & 07;
316 op->scale = 1 << scale;
319 op->indexreg = -1; /* ESP/RSP/R12 cannot be an index */
321 op->indexreg = nasm_rd_reg64[index | ((rex & REX_X) ? 8 : 0)];
323 op->indexreg = nasm_rd_reg32[index | ((rex & REX_X) ? 8 : 0)];
325 if (base == 5 && mod == 0) {
327 mod = 2; /* Fake disp32 */
329 op->basereg = nasm_rd_reg64[base | ((rex & REX_B) ? 8 : 0)];
331 op->basereg = nasm_rd_reg32[base | ((rex & REX_B) ? 8 : 0)];
339 op->segment |= SEG_NODISP;
342 op->segment |= SEG_DISP8;
343 op->offset = gets8(data);
347 op->segment |= SEG_DISP32;
348 op->offset = gets32(data);
357 * Determine whether the instruction template in t corresponds to the data
358 * stream in data. Return the number of bytes matched if so.
360 #define case4(x) case (x): case (x)+1: case (x)+2: case (x)+3
362 static int matches(const struct itemplate *t, uint8_t *data,
363 const struct prefix_info *prefix, int segsize, insn *ins)
365 uint8_t *r = (uint8_t *)(t->code);
366 uint8_t *origdata = data;
367 bool a_used = false, o_used = false;
368 enum prefixes drep = 0;
369 uint8_t lock = prefix->lock;
370 int osize = prefix->osize;
371 int asize = prefix->asize;
374 int s_field_for = -1; /* No 144/154 series code encountered */
376 for (i = 0; i < MAX_OPERANDS; i++) {
377 ins->oprs[i].segment = ins->oprs[i].disp_size =
378 (segsize == 64 ? SEG_64BIT : segsize == 32 ? SEG_32BIT : 0);
381 ins->rex = prefix->rex;
382 memset(ins->prefixes, 0, sizeof ins->prefixes);
384 if (t->flags & (segsize == 64 ? IF_NOLONG : IF_LONG))
387 if (prefix->rep == 0xF2)
389 else if (prefix->rep == 0xF3)
392 while ((c = *r++) != 0) {
393 opx = &ins->oprs[c & 3];
407 ins->oprs[0].basereg = 0;
410 ins->oprs[0].basereg = 2;
413 ins->oprs[0].basereg = 3;
423 ins->oprs[0].basereg = 4;
426 ins->oprs[0].basereg = 5;
436 ins->oprs[0].basereg = 0;
439 ins->oprs[0].basereg = 1;
442 ins->oprs[0].basereg = 2;
445 ins->oprs[0].basereg = 3;
455 ins->oprs[0].basereg = 4;
458 ins->oprs[0].basereg = 5;
467 int t = *r++, d = *data++;
468 if (d < t || d > t + 7)
471 opx->basereg = (d-t)+
472 (ins->rex & REX_B ? 8 : 0);
473 opx->segment |= SEG_RMREG;
479 opx->offset = (int8_t)*data++;
480 opx->segment |= SEG_SIGNED;
484 opx->offset = *data++;
488 opx->offset = *data++;
492 opx->offset = getu16(data);
498 opx->offset = getu32(data);
501 opx->offset = getu16(data);
504 if (segsize != asize)
505 opx->disp_size = asize;
509 opx->offset = getu32(data);
516 opx->offset = getu16(data);
522 opx->offset = getu32(data);
528 opx->offset = getu64(data);
536 opx->offset = gets8(data++);
537 opx->segment |= SEG_RELATIVE;
541 opx->offset = getu64(data);
546 opx->offset = gets16(data);
548 opx->segment |= SEG_RELATIVE;
549 opx->segment &= ~SEG_32BIT;
553 opx->segment |= SEG_RELATIVE;
555 opx->offset = gets16(data);
557 opx->segment &= ~(SEG_32BIT|SEG_64BIT);
558 } else if (osize == 32) {
559 opx->offset = gets32(data);
561 opx->segment &= ~SEG_64BIT;
562 opx->segment |= SEG_32BIT;
564 if (segsize != osize) {
566 (opx->type & ~SIZE_MASK)
567 | ((osize == 16) ? BITS16 : BITS32);
572 opx->offset = gets32(data);
574 opx->segment |= SEG_32BIT | SEG_RELATIVE;
583 opx->segment |= SEG_RMREG;
584 data = do_ea(data, modrm, asize, segsize,
585 &ins->oprs[(c >> 3) & 3], ins);
588 opx->basereg = ((modrm >> 3)&7)+
589 (ins->rex & REX_R ? 8 : 0);
594 if (s_field_for == (c & 3)) {
595 opx->offset = gets8(data);
598 opx->offset = getu16(data);
605 s_field_for = (*data & 0x02) ? c & 3 : -1;
606 if ((*data++ & ~0x02) != *r++)
611 if (s_field_for == (c & 3)) {
612 opx->offset = gets8(data);
615 opx->offset = getu32(data);
622 ins->drexdst = c & 3;
626 ins->rex |= REX_D|REX_OC;
627 ins->drexdst = c & 3;
631 data = do_drex(data, ins);
638 uint8_t ximm = *data++;
640 ins->oprs[c >> 3].basereg = ximm >> 4;
641 ins->oprs[c >> 3].segment |= SEG_RMREG;
642 ins->oprs[c & 7].offset = ximm & 15;
648 uint8_t ximm = *data++;
654 ins->oprs[c >> 4].basereg = ximm >> 4;
655 ins->oprs[c >> 4].segment |= SEG_RMREG;
661 uint8_t ximm = *data++;
664 ins->oprs[c].basereg = ximm >> 4;
665 ins->oprs[c].segment |= SEG_RMREG;
679 if (((modrm >> 3) & 07) != (c & 07))
680 return false; /* spare field doesn't match up */
681 data = do_ea(data, modrm, asize, segsize,
682 &ins->oprs[(c >> 3) & 07], ins);
693 if ((prefix->rex & (REX_V|REX_D|REX_P)) != REX_V)
696 if ((vexm & 0x1f) != prefix->vex_m)
699 switch (vexwlp & 030) {
701 if (prefix->rex & REX_W)
705 if (!(prefix->rex & REX_W))
709 break; /* XXX: Need to do anything special here? */
712 if ((vexwlp & 007) != prefix->vex_lp)
715 opx->segment |= SEG_RMREG;
716 opx->basereg = prefix->vex_v;
725 if ((prefix->rex & (REX_V|REX_D|REX_P)) != REX_V)
728 if ((vexm & 0x1f) != prefix->vex_m)
731 switch (vexwlp & 030) {
733 if (ins->rex & REX_W)
737 if (!(ins->rex & REX_W))
741 break; /* Need to do anything special here? */
744 if ((vexwlp & 007) != prefix->vex_lp)
747 if (prefix->vex_v != 0)
768 if (asize != segsize)
782 if (prefix->rex & REX_B)
787 if (prefix->rex & REX_X)
792 if (prefix->rex & REX_R)
797 if (prefix->rex & REX_W)
816 if (osize != (segsize == 16) ? 16 : 32)
823 ins->rex |= REX_W; /* 64-bit only instruction */
829 if (!(ins->rex & (REX_P|REX_W)) || osize != 64)
836 int t = *r++, d = *data++;
837 if (d < t || d > t + 15)
840 ins->condition = d - t;
850 if (prefix->rep != 0xF2)
856 if (prefix->rep != 0xF3)
877 if (prefix->osp || prefix->rep)
882 if (!prefix->osp || prefix->rep)
887 if (prefix->osp || prefix->rep != 0xf2)
892 if (prefix->osp || prefix->rep != 0xf3)
919 return false; /* Unknown code */
923 /* REX cannot be combined with DREX or VEX */
924 if ((ins->rex & (REX_D|REX_V)) && (prefix->rex & REX_P))
928 * Check for unused rep or a/o prefixes.
930 for (i = 0; i < t->operands; i++) {
931 if (ins->oprs[i].segment != SEG_RMREG)
936 if (ins->prefixes[PPS_LREP])
938 ins->prefixes[PPS_LREP] = P_LOCK;
941 if (ins->prefixes[PPS_LREP])
943 ins->prefixes[PPS_LREP] = drep;
946 if (osize != ((segsize == 16) ? 16 : 32)) {
947 enum prefixes pfx = 0;
961 if (ins->prefixes[PPS_OSIZE])
963 ins->prefixes[PPS_OSIZE] = pfx;
966 if (!a_used && asize != segsize) {
967 if (ins->prefixes[PPS_ASIZE])
969 ins->prefixes[PPS_ASIZE] = asize == 16 ? P_A16 : P_A32;
972 /* Fix: check for redundant REX prefixes */
974 return data - origdata;
977 /* Condition names for disassembly, sorted by x86 code */
978 static const char * const condition_name[16] = {
979 "o", "no", "c", "nc", "z", "nz", "na", "a",
980 "s", "ns", "pe", "po", "l", "nl", "ng", "g"
983 int32_t disasm(uint8_t *data, char *output, int outbufsize, int segsize,
984 int32_t offset, int autosync, uint32_t prefer)
986 const struct itemplate * const *p, * const *best_p;
987 const struct disasm_index *ix;
989 int length, best_length = 0;
991 int i, slen, colon, n;
995 uint32_t goodness, best;
997 struct prefix_info prefix;
1000 memset(&ins, 0, sizeof ins);
1003 * Scan for prefixes.
1005 memset(&prefix, 0, sizeof prefix);
1006 prefix.asize = segsize;
1007 prefix.osize = (segsize == 64) ? 32 : segsize;
1012 while (!end_prefix) {
1016 prefix.rep = *data++;
1019 prefix.lock = *data++;
1022 segover = "cs", prefix.seg = *data++;
1025 segover = "ss", prefix.seg = *data++;
1028 segover = "ds", prefix.seg = *data++;
1031 segover = "es", prefix.seg = *data++;
1034 segover = "fs", prefix.seg = *data++;
1037 segover = "gs", prefix.seg = *data++;
1040 prefix.osize = (segsize == 16) ? 32 : 16;
1041 prefix.osp = *data++;
1044 prefix.asize = (segsize == 32) ? 16 : 32;
1045 prefix.asp = *data++;
1049 if (segsize == 64 || (data[1] & 0xc0) == 0xc0) {
1050 prefix.vex[0] = *data++;
1051 prefix.vex[1] = *data++;
1052 if (prefix.vex[0] == 0xc4)
1053 prefix.vex[2] = *data++;
1056 if (prefix.vex[0] == 0xc4) {
1057 prefix.rex |= (~prefix.vex[1] >> 5) & 7; /* REX_RXB */
1058 prefix.rex |= (prefix.vex[2] >> (7-3)) & REX_W;
1059 prefix.vex_m = prefix.vex[1] & 0x1f;
1060 prefix.vex_v = (~prefix.vex[2] >> 3) & 15;
1061 prefix.vex_lp = prefix.vex[2] & 7;
1063 prefix.rex |= (~prefix.vex[1] >> (7-2)) & REX_R;
1065 prefix.vex_v = (~prefix.vex[1] >> 3) & 15;
1066 prefix.vex_lp = prefix.vex[1] & 7;
1086 if (segsize == 64) {
1087 prefix.rex = *data++;
1088 if (prefix.rex & REX_W)
1099 best = -1; /* Worst possible */
1101 best_pref = INT_MAX;
1104 ix = itable + *dp++;
1105 while (ix->n == -1) {
1106 ix = (const struct disasm_index *)ix->p + *dp++;
1109 p = (const struct itemplate * const *)ix->p;
1110 for (n = ix->n; n; n--, p++) {
1111 if ((length = matches(*p, data, &prefix, segsize, &tmp_ins))) {
1114 * Final check to make sure the types of r/m match up.
1115 * XXX: Need to make sure this is actually correct.
1117 for (i = 0; i < (*p)->operands; i++) {
1118 if (!((*p)->opd[i] & SAME_AS) &&
1120 /* If it's a mem-only EA but we have a
1122 ((tmp_ins.oprs[i].segment & SEG_RMREG) &&
1123 !(MEMORY & ~(*p)->opd[i])) ||
1124 /* If it's a reg-only EA but we have a memory
1126 (!(tmp_ins.oprs[i].segment & SEG_RMREG) &&
1127 !(REG_EA & ~(*p)->opd[i]) &&
1128 !((*p)->opd[i] & REG_SMASK)) ||
1129 /* Register type mismatch (eg FS vs REG_DESS):
1131 ((((*p)->opd[i] & (REGISTER | FPUREG)) ||
1132 (tmp_ins.oprs[i].segment & SEG_RMREG)) &&
1133 !whichreg((*p)->opd[i],
1134 tmp_ins.oprs[i].basereg, tmp_ins.rex))
1142 * Note: we always prefer instructions which incorporate
1143 * prefixes in the instructions themselves. This is to allow
1144 * e.g. PAUSE to be preferred to REP NOP, and deal with
1145 * MMX/SSE instructions where prefixes are used to select
1146 * between MMX and SSE register sets or outright opcode
1151 goodness = ((*p)->flags & IF_PFMASK) ^ prefer;
1153 for (i = 0; i < MAXPREFIX; i++)
1154 if (tmp_ins.prefixes[i])
1156 if (nprefix < best_pref ||
1157 (nprefix == best_pref && goodness < best)) {
1158 /* This is the best one found so far */
1161 best_pref = nprefix;
1162 best_length = length;
1170 return 0; /* no instruction was matched */
1172 /* Pick the best match */
1174 length = best_length;
1178 /* TODO: snprintf returns the value that the string would have if
1179 * the buffer were long enough, and not the actual length of
1180 * the returned string, so each instance of using the return
1181 * value of snprintf should actually be checked to assure that
1182 * the return value is "sane." Maybe a macro wrapper could
1183 * be used for that purpose.
1185 for (i = 0; i < MAXPREFIX; i++)
1186 switch (ins.prefixes[i]) {
1188 slen += snprintf(output + slen, outbufsize - slen, "lock ");
1191 slen += snprintf(output + slen, outbufsize - slen, "rep ");
1194 slen += snprintf(output + slen, outbufsize - slen, "repe ");
1197 slen += snprintf(output + slen, outbufsize - slen, "repne ");
1200 slen += snprintf(output + slen, outbufsize - slen, "a16 ");
1203 slen += snprintf(output + slen, outbufsize - slen, "a32 ");
1206 slen += snprintf(output + slen, outbufsize - slen, "a64 ");
1209 slen += snprintf(output + slen, outbufsize - slen, "o16 ");
1212 slen += snprintf(output + slen, outbufsize - slen, "o32 ");
1215 slen += snprintf(output + slen, outbufsize - slen, "o64 ");
1222 if (i >= FIRST_COND_OPCODE) {
1223 slen += snprintf(output + slen, outbufsize - slen, "%s%s",
1224 nasm_cond_insn_names[i-FIRST_COND_OPCODE],
1225 condition_name[ins.condition]);
1227 slen += snprintf(output + slen, outbufsize - slen, "%s",
1228 nasm_insn_names[i]);
1231 length += data - origdata; /* fix up for prefixes */
1232 for (i = 0; i < (*p)->operands; i++) {
1233 opflags_t t = (*p)->opd[i];
1234 const operand *o = &ins.oprs[i];
1238 o = &ins.oprs[t & ~SAME_AS];
1239 t = (*p)->opd[t & ~SAME_AS];
1242 output[slen++] = (colon ? ':' : i == 0 ? ' ' : ',');
1245 if (o->segment & SEG_RELATIVE) {
1246 offs += offset + length;
1248 * sort out wraparound
1250 if (!(o->segment & (SEG_32BIT|SEG_64BIT)))
1252 else if (segsize != 64)
1256 * add sync marker, if autosync is on
1267 if ((t & (REGISTER | FPUREG)) ||
1268 (o->segment & SEG_RMREG)) {
1270 reg = whichreg(t, o->basereg, ins.rex);
1272 slen += snprintf(output + slen, outbufsize - slen, "to ");
1273 slen += snprintf(output + slen, outbufsize - slen, "%s",
1274 nasm_reg_names[reg-EXPR_REG_START]);
1275 } else if (!(UNITY & ~t)) {
1276 output[slen++] = '1';
1277 } else if (t & IMMEDIATE) {
1280 snprintf(output + slen, outbufsize - slen, "byte ");
1281 if (o->segment & SEG_SIGNED) {
1284 output[slen++] = '-';
1286 output[slen++] = '+';
1288 } else if (t & BITS16) {
1290 snprintf(output + slen, outbufsize - slen, "word ");
1291 } else if (t & BITS32) {
1293 snprintf(output + slen, outbufsize - slen, "dword ");
1294 } else if (t & BITS64) {
1296 snprintf(output + slen, outbufsize - slen, "qword ");
1297 } else if (t & NEAR) {
1299 snprintf(output + slen, outbufsize - slen, "near ");
1300 } else if (t & SHORT) {
1302 snprintf(output + slen, outbufsize - slen, "short ");
1305 snprintf(output + slen, outbufsize - slen, "0x%"PRIx64"",
1307 } else if (!(MEM_OFFS & ~t)) {
1309 snprintf(output + slen, outbufsize - slen,
1310 "[%s%s%s0x%"PRIx64"]",
1311 (segover ? segover : ""),
1312 (segover ? ":" : ""),
1313 (o->disp_size == 64 ? "qword " :
1314 o->disp_size == 32 ? "dword " :
1315 o->disp_size == 16 ? "word " : ""), offs);
1317 } else if (!(REGMEM & ~t)) {
1318 int started = false;
1321 snprintf(output + slen, outbufsize - slen, "byte ");
1324 snprintf(output + slen, outbufsize - slen, "word ");
1327 snprintf(output + slen, outbufsize - slen, "dword ");
1330 snprintf(output + slen, outbufsize - slen, "qword ");
1333 snprintf(output + slen, outbufsize - slen, "tword ");
1336 snprintf(output + slen, outbufsize - slen, "oword ");
1339 snprintf(output + slen, outbufsize - slen, "yword ");
1341 slen += snprintf(output + slen, outbufsize - slen, "far ");
1344 snprintf(output + slen, outbufsize - slen, "near ");
1345 output[slen++] = '[';
1347 slen += snprintf(output + slen, outbufsize - slen, "%s",
1348 (o->disp_size == 64 ? "qword " :
1349 o->disp_size == 32 ? "dword " :
1350 o->disp_size == 16 ? "word " :
1352 if (o->eaflags & EAF_REL)
1353 slen += snprintf(output + slen, outbufsize - slen, "rel ");
1356 snprintf(output + slen, outbufsize - slen, "%s:",
1360 if (o->basereg != -1) {
1361 slen += snprintf(output + slen, outbufsize - slen, "%s",
1362 nasm_reg_names[(o->basereg-EXPR_REG_START)]);
1365 if (o->indexreg != -1) {
1367 output[slen++] = '+';
1368 slen += snprintf(output + slen, outbufsize - slen, "%s",
1369 nasm_reg_names[(o->indexreg-EXPR_REG_START)]);
1372 snprintf(output + slen, outbufsize - slen, "*%d",
1378 if (o->segment & SEG_DISP8) {
1380 uint8_t offset = offs;
1381 if ((int8_t)offset < 0) {
1388 snprintf(output + slen, outbufsize - slen, "%s0x%"PRIx8"",
1390 } else if (o->segment & SEG_DISP16) {
1392 uint16_t offset = offs;
1393 if ((int16_t)offset < 0 && started) {
1397 prefix = started ? "+" : "";
1400 snprintf(output + slen, outbufsize - slen,
1401 "%s0x%"PRIx16"", prefix, offset);
1402 } else if (o->segment & SEG_DISP32) {
1403 if (prefix.asize == 64) {
1405 uint64_t offset = (int64_t)(int32_t)offs;
1406 if ((int32_t)offs < 0 && started) {
1410 prefix = started ? "+" : "";
1413 snprintf(output + slen, outbufsize - slen,
1414 "%s0x%"PRIx64"", prefix, offset);
1417 uint32_t offset = offs;
1418 if ((int32_t) offset < 0 && started) {
1422 prefix = started ? "+" : "";
1425 snprintf(output + slen, outbufsize - slen,
1426 "%s0x%"PRIx32"", prefix, offset);
1429 output[slen++] = ']';
1432 snprintf(output + slen, outbufsize - slen, "<operand%d>",
1436 output[slen] = '\0';
1437 if (segover) { /* unused segment override */
1439 int count = slen + 1;
1441 p[count + 3] = p[count];
1442 strncpy(output, segover, 2);
1448 int32_t eatbyte(uint8_t *data, char *output, int outbufsize)
1450 snprintf(output, outbufsize, "db 0x%02X", *data);