1 /* -*- mode: C; c-basic-offset: 3; -*- */
2
3 /*---------------------------------------------------------------*/
4 /*--- begin s390_disasm.c ---*/
5 /*---------------------------------------------------------------*/
6
7 /*
8 This file is part of Valgrind, a dynamic binary instrumentation
9 framework.
10
11 Copyright IBM Corp. 2010-2017
12
13 This program is free software; you can redistribute it and/or
14 modify it under the terms of the GNU General Public License as
15 published by the Free Software Foundation; either version 2 of the
16 License, or (at your option) any later version.
17
18 This program is distributed in the hope that it will be useful, but
19 WITHOUT ANY WARRANTY; without even the implied warranty of
20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21 General Public License for more details.
22
23 You should have received a copy of the GNU General Public License
24 along with this program; if not, write to the Free Software
25 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
26 02110-1301, USA.
27
28 The GNU General Public License is contained in the file COPYING.
29 */
30
31 /* Contributed by Florian Krohm */
32
33 #include <stdarg.h>
34 #include "libvex_basictypes.h"
35 #include "main_util.h" // vassert
36 #include "main_globals.h" // vex_traceflags
37 #include "s390_defs.h" // S390_MAX_MNEMONIC_LEN
38 #include "s390_disasm.h"
39
40
41 /* Return the mnemonic padded with blanks to its right */
42 static const HChar *
mnemonic(const HChar * mnm)43 mnemonic(const HChar *mnm)
44 {
45 vassert(vex_strlen(mnm) <= S390_MAX_MNEMONIC_LEN);
46
47 static HChar buf[S390_MAX_MNEMONIC_LEN + 1];
48
49 vex_sprintf(buf, "%-*s", S390_MAX_MNEMONIC_LEN, mnm);
50
51 return buf;
52 }
53
54
55 /* Return the name of a general purpose register for dis-assembly purposes. */
56 static const HChar *
gpr_operand(UInt archreg)57 gpr_operand(UInt archreg)
58 {
59 static const HChar names[16][5] = {
60 "%r0", "%r1", "%r2", "%r3",
61 "%r4", "%r5", "%r6", "%r7",
62 "%r8", "%r9", "%r10", "%r11",
63 "%r12", "%r13", "%r14", "%r15",
64 };
65
66 vassert(archreg < 16);
67
68 return names[archreg];
69 }
70
71
72 /* Return the name of a floating point register for dis-assembly purposes. */
73 static const HChar *
fpr_operand(UInt archreg)74 fpr_operand(UInt archreg)
75 {
76 static const HChar names[16][5] = {
77 "%f0", "%f1", "%f2", "%f3",
78 "%f4", "%f5", "%f6", "%f7",
79 "%f8", "%f9", "%f10", "%f11",
80 "%f12", "%f13", "%f14", "%f15",
81 };
82
83 vassert(archreg < 16);
84
85 return names[archreg];
86 }
87
88
89 /* Return the name of an access register for dis-assembly purposes. */
90 static const HChar *
ar_operand(UInt archreg)91 ar_operand(UInt archreg)
92 {
93 static const HChar names[16][5] = {
94 "%a0", "%a1", "%a2", "%a3",
95 "%a4", "%a5", "%a6", "%a7",
96 "%a8", "%a9", "%a10", "%a11",
97 "%a12", "%a13", "%a14", "%a15",
98 };
99
100 vassert(archreg < 16);
101
102 return names[archreg];
103 }
104
105
106 /* Build and return the extended mnemonic for the compare and branch
107 opcodes as introduced by z10. See also the opcodes in file
108 opcodes/s390-opc.txt (from binutils) that have a '$' in their name. */
109 static const HChar *
cab_operand(const HChar * base,UInt mask)110 cab_operand(const HChar *base, UInt mask)
111 {
112 HChar *to;
113 const HChar *from;
114
115 static HChar buf[S390_MAX_MNEMONIC_LEN + 1];
116
117 static const HChar suffix[8][3] = {
118 "", "h", "l", "ne", "e", "nl", "nh", ""
119 };
120
121 /* Guard against buffer overflow */
122 vassert(vex_strlen(base) + sizeof suffix[0] <= sizeof buf);
123
124 /* strcpy(buf, from); */
125 for (from = base, to = buf; *from; ++from, ++to) {
126 *to = *from;
127 }
128 /* strcat(buf, suffix); */
129 for (from = suffix[mask >> 1]; *from; ++from, ++to) {
130 *to = *from;
131 }
132 *to = '\0';
133
134 return buf;
135 }
136
137
138 /* Common function used to construct a mnemonic based on a condition code
139 mask. */
140 static const HChar *
construct_mnemonic(const HChar * prefix,const HChar * suffix,UInt mask)141 construct_mnemonic(const HChar *prefix, const HChar *suffix, UInt mask)
142 {
143 HChar *to;
144 const HChar *from;
145
146 static HChar buf[S390_MAX_MNEMONIC_LEN + 1];
147
148 static HChar mask_id[16][4] = {
149 "", /* 0 -> unused */
150 "o", "h", "nle", "l", "nhe", "lh", "ne",
151 "e", "nlh", "he", "nl", "le", "nh", "no",
152 "" /* 15 -> unused */
153 };
154
155 /* Guard against buffer overflow */
156 vassert(vex_strlen(prefix) + vex_strlen(suffix) +
157 sizeof mask_id[0] <= sizeof buf);
158
159 /* strcpy(buf, prefix); */
160 for (from = prefix, to = buf; *from; ++from, ++to) {
161 *to = *from;
162 }
163 /* strcat(buf, mask_id); */
164 for (from = mask_id[mask]; *from; ++from, ++to) {
165 *to = *from;
166 }
167 /* strcat(buf, suffix); */
168 for (from = suffix; *from; ++from, ++to) {
169 *to = *from;
170 }
171 *to = '\0';
172
173 return buf;
174 }
175
176
177 /* Return the special mnemonic for the BCR opcode */
178 static const HChar *
bcr_operand(UInt m1)179 bcr_operand(UInt m1)
180 {
181 if (m1 == 0) return "nopr";
182 if (m1 == 15) return "br";
183
184 return construct_mnemonic("b", "r", m1);
185 }
186
187
188 /* Return the special mnemonic for the BC opcode */
189 static const HChar *
bc_operand(UInt m1)190 bc_operand(UInt m1)
191 {
192 if (m1 == 0) return "nop";
193 if (m1 == 15) return "b";
194
195 return construct_mnemonic("b", "", m1);
196 }
197
198
199 /* Return the special mnemonic for the BRC opcode */
200 static const HChar *
brc_operand(UInt m1)201 brc_operand(UInt m1)
202 {
203 if (m1 == 0) return "brc";
204 if (m1 == 15) return "j";
205
206 return construct_mnemonic("j", "", m1);
207 }
208
209
210 /* Return the special mnemonic for the BRCL opcode */
211 static const HChar *
brcl_operand(UInt m1)212 brcl_operand(UInt m1)
213 {
214 if (m1 == 0) return "brcl";
215 if (m1 == 15) return "jg";
216
217 return construct_mnemonic("jg", "", m1);
218 }
219
220
221 /* Return the special mnemonic for a conditional load/store opcode */
222 static const HChar *
cls_operand(Int kind,UInt mask)223 cls_operand(Int kind, UInt mask)
224 {
225 const HChar *prefix;
226
227 switch (kind) {
228 case S390_XMNM_LOCR: prefix = "locr"; break;
229 case S390_XMNM_LOCGR: prefix = "locgr"; break;
230 case S390_XMNM_LOC: prefix = "loc"; break;
231 case S390_XMNM_LOCG: prefix = "locg"; break;
232 case S390_XMNM_STOC: prefix = "stoc"; break;
233 case S390_XMNM_STOCG: prefix = "stocg"; break;
234 default:
235 vpanic("cls_operand");
236 }
237
238 return construct_mnemonic(prefix, "", mask);
239 }
240
241
242 /* An operand with a base register, an index register, and a displacement.
243 If the displacement is signed, the rightmost 20 bit of D need to be
244 sign extended */
245 static HChar *
dxb_operand(HChar * p,UInt d,UInt x,UInt b,Bool displacement_is_signed)246 dxb_operand(HChar *p, UInt d, UInt x, UInt b, Bool displacement_is_signed)
247 {
248 if (displacement_is_signed) {
249 Int displ = (Int)(d << 12) >> 12; /* sign extend */
250
251 p += vex_sprintf(p, "%d", displ);
252 } else {
253 p += vex_sprintf(p, "%u", d);
254 }
255 if (x != 0) {
256 p += vex_sprintf(p, "(%s", gpr_operand(x));
257 if (b != 0) {
258 p += vex_sprintf(p, ",%s", gpr_operand(b));
259 }
260 p += vex_sprintf(p, ")");
261 } else {
262 if (b != 0) {
263 p += vex_sprintf(p, "(%s)", gpr_operand(b));
264 }
265 }
266
267 return p;
268 }
269
270
271 /* An operand with base register, unsigned length, and a 12-bit
272 unsigned displacement */
273 static HChar *
udlb_operand(HChar * p,UInt d,UInt length,UInt b)274 udlb_operand(HChar *p, UInt d, UInt length, UInt b)
275 {
276 p += vex_sprintf(p, "%u", d);
277 p += vex_sprintf(p, "(%u", length + 1); // actual length is +1
278 if (b != 0) {
279 p += vex_sprintf(p, ",%s", gpr_operand(b));
280 }
281 p += vex_sprintf(p, ")");
282
283 return p;
284 }
285
286
287 /* The first argument is the command that says how to write the disassembled
288 insn. It is understood that the mnemonic comes first and that arguments
289 are separated by a ','. The command holds the arguments. Each argument is
290 encoded using a 4-bit S390_ARG_xyz value. The first argument is placed
291 in the least significant bits of the command and so on. There are at most
292 5 arguments in an insn and a sentinel (S390_ARG_DONE) is needed to identify
293 the end of the argument list. 6 * 4 = 24 bits are required for the
294 command. */
295 void
s390_disasm(UInt command,...)296 s390_disasm(UInt command, ...)
297 {
298 va_list args;
299 UInt argkind;
300 HChar buf[128]; /* holds the disassembled insn */
301 HChar *p;
302 HChar separator;
303 Int mask_suffix = -1;
304
305 va_start(args, command);
306
307 p = buf;
308 separator = 0;
309
310 while (42) {
311 argkind = command & 0xF;
312 command >>= 4;
313
314 if (argkind == S390_ARG_DONE) goto done;
315
316 if (argkind == S390_ARG_CABM) separator = 0; /* optional */
317
318 /* Write out the separator */
319 if (separator) *p++ = separator;
320
321 /* argument */
322 switch (argkind) {
323 case S390_ARG_MNM:
324 p += vex_sprintf(p, "%s", mnemonic(va_arg(args, HChar *)));
325 separator = ' ';
326 continue;
327
328 case S390_ARG_XMNM: {
329 UInt mask, kind;
330 const HChar *mnm;
331
332 kind = va_arg(args, UInt);
333
334 separator = ' ';
335 switch (kind) {
336 case S390_XMNM_BC:
337 case S390_XMNM_BCR:
338 mask = va_arg(args, UInt);
339 mnm = kind == S390_XMNM_BCR ? bcr_operand(mask) : bc_operand(mask);
340 p += vex_sprintf(p, "%s", mnemonic(mnm));
341 /* mask == 0 is a NOP and has no argument */
342 if (mask == 0) goto done;
343 break;
344
345 case S390_XMNM_BRC:
346 case S390_XMNM_BRCL:
347 mask = va_arg(args, UInt);
348 mnm = kind == S390_XMNM_BRC ? brc_operand(mask) : brcl_operand(mask);
349 p += vex_sprintf(p, "%s", mnemonic(mnm));
350
351 /* mask == 0 has no special mnemonic */
352 if (mask == 0) {
353 p += vex_sprintf(p, " 0");
354 separator = ',';
355 }
356 break;
357
358 case S390_XMNM_CAB:
359 mnm = va_arg(args, HChar *);
360 mask = va_arg(args, UInt);
361 p += vex_sprintf(p, "%s", mnemonic(cab_operand(mnm, mask)));
362 break;
363
364 case S390_XMNM_LOCR:
365 case S390_XMNM_LOCGR:
366 case S390_XMNM_LOC:
367 case S390_XMNM_LOCG:
368 case S390_XMNM_STOC:
369 case S390_XMNM_STOCG:
370 mask = va_arg(args, UInt);
371 mnm = cls_operand(kind, mask);
372 p += vex_sprintf(p, "%s", mnemonic(mnm));
373 /* There are no special opcodes when mask == 0 or 15. In that case
374 the integer mask is appended as the final operand */
375 if (mask == 0 || mask == 15) mask_suffix = mask;
376 break;
377 }
378 }
379 continue;
380
381 case S390_ARG_GPR:
382 p += vex_sprintf(p, "%s", gpr_operand(va_arg(args, UInt)));
383 break;
384
385 case S390_ARG_FPR:
386 p += vex_sprintf(p, "%s", fpr_operand(va_arg(args, UInt)));
387 break;
388
389 case S390_ARG_AR:
390 p += vex_sprintf(p, "%s", ar_operand(va_arg(args, UInt)));
391 break;
392
393 case S390_ARG_UINT:
394 p += vex_sprintf(p, "%u", va_arg(args, UInt));
395 break;
396
397 case S390_ARG_INT:
398 p += vex_sprintf(p, "%d", (Int)(va_arg(args, UInt)));
399 break;
400
401 case S390_ARG_PCREL: {
402 Long offset = va_arg(args, Int);
403
404 /* Convert # halfwords to # bytes */
405 offset <<= 1;
406
407 if (offset < 0) {
408 p += vex_sprintf(p, ".%lld", offset);
409 } else {
410 p += vex_sprintf(p, ".+%lld", offset);
411 }
412 break;
413 }
414
415 case S390_ARG_SDXB: {
416 UInt dh, dl, x, b;
417
418 dh = va_arg(args, UInt);
419 dl = va_arg(args, UInt);
420 x = va_arg(args, UInt);
421 b = va_arg(args, UInt);
422
423 p = dxb_operand(p, (dh << 12) | dl, x, b, 1 /* signed_displacement */);
424 break;
425 }
426
427 case S390_ARG_UDXB: {
428 UInt d, x, b;
429
430 d = va_arg(args, UInt);
431 x = va_arg(args, UInt);
432 b = va_arg(args, UInt);
433
434 p = dxb_operand(p, d, x, b, 0 /* signed_displacement */);
435 break;
436 }
437
438 case S390_ARG_UDLB: {
439 UInt d, l, b;
440
441 d = va_arg(args, UInt);
442 l = va_arg(args, UInt);
443 b = va_arg(args, UInt);
444
445 p = udlb_operand(p, d, l, b);
446 break;
447 }
448
449 case S390_ARG_CABM: {
450 UInt mask;
451
452 mask = va_arg(args, UInt) & 0xE;
453 if (mask == 0 || mask == 14) {
454 p += vex_sprintf(p, ",%u", mask);
455 }
456 break;
457 }
458 }
459
460 separator = ',';
461 }
462
463 done:
464 va_end(args);
465
466 if (mask_suffix != -1)
467 p += vex_sprintf(p, ",%d", mask_suffix);
468 *p = '\0';
469
470 vassert(p < buf + sizeof buf); /* detect buffer overwrite */
471
472 /* Finally, write out the disassembled insn */
473 vex_printf("%s\n", buf);
474 }
475
476 /*---------------------------------------------------------------*/
477 /*--- end s390_disasm.c ---*/
478 /*---------------------------------------------------------------*/
479