1 /* s390-dis.c -- Disassemble S390 instructions
2 Copyright (C) 2000-2024 Free Software Foundation, Inc.
3 Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
4
5 This file is part of the GNU opcodes library.
6
7 This library is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
11
12 It is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this file; see the file COPYING. If not, write to the
19 Free Software Foundation, 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
21
22 #include "sysdep.h"
23 #include <stdio.h>
24 #include "ansidecl.h"
25 #include "disassemble.h"
26 #include "opintl.h"
27 #include "opcode/s390.h"
28 #include "libiberty.h"
29 #include "dis-asm.h"
30
31 static int opc_index[256];
32 static int current_arch_mask = 0;
33 static int option_use_insn_len_bits_p = 0;
34 static int option_print_insn_desc = 0;
35
36 typedef struct
37 {
38 const char *name;
39 const char *description;
40 } s390_options_t;
41
42 static const s390_options_t options[] =
43 {
44 { "esa" , N_("Disassemble in ESA architecture mode") },
45 { "zarch", N_("Disassemble in z/Architecture mode") },
46 { "insnlength", N_("Print unknown instructions according to "
47 "length from first two bits") },
48 { "insndesc", N_("Print instruction description as comment") },
49 };
50
51 /* Set up index table for first opcode byte. */
52
53 void
disassemble_init_s390(struct disassemble_info * info)54 disassemble_init_s390 (struct disassemble_info *info)
55 {
56 int i;
57 const char *p;
58
59 memset (opc_index, 0, sizeof (opc_index));
60
61 /* Reverse order, such that each opc_index ends up pointing to the
62 first matching entry instead of the last. */
63 for (i = s390_num_opcodes; i--; )
64 opc_index[s390_opcodes[i].opcode[0]] = i;
65
66 current_arch_mask = 1 << S390_OPCODE_ZARCH;
67 option_use_insn_len_bits_p = 0;
68 option_print_insn_desc = 0;
69
70 for (p = info->disassembler_options; p != NULL; )
71 {
72 if (startswith (p, "esa"))
73 current_arch_mask = 1 << S390_OPCODE_ESA;
74 else if (startswith (p, "zarch"))
75 current_arch_mask = 1 << S390_OPCODE_ZARCH;
76 else if (startswith (p, "insnlength"))
77 option_use_insn_len_bits_p = 1;
78 else if (startswith (p, "insndesc"))
79 option_print_insn_desc = 1;
80 else
81 /* xgettext:c-format */
82 opcodes_error_handler (_("unknown S/390 disassembler option: %s"), p);
83
84 p = strchr (p, ',');
85 if (p != NULL)
86 p++;
87 }
88 }
89
90 /* Derive the length of an instruction from its first byte. */
91
92 static inline int
s390_insn_length(const bfd_byte * buffer)93 s390_insn_length (const bfd_byte *buffer)
94 {
95 /* 00xxxxxx -> 2, 01xxxxxx/10xxxxxx -> 4, 11xxxxxx -> 6. */
96 return ((buffer[0] >> 6) + 3) & ~1U;
97 }
98
99 /* Match the instruction in BUFFER against the given OPCODE, excluding
100 the first byte. */
101
102 static inline int
s390_insn_matches_opcode(const bfd_byte * buffer,const struct s390_opcode * opcode)103 s390_insn_matches_opcode (const bfd_byte *buffer,
104 const struct s390_opcode *opcode)
105 {
106 return (buffer[1] & opcode->mask[1]) == opcode->opcode[1]
107 && (buffer[2] & opcode->mask[2]) == opcode->opcode[2]
108 && (buffer[3] & opcode->mask[3]) == opcode->opcode[3]
109 && (buffer[4] & opcode->mask[4]) == opcode->opcode[4]
110 && (buffer[5] & opcode->mask[5]) == opcode->opcode[5];
111 }
112
113 union operand_value
114 {
115 int i;
116 unsigned int u;
117 };
118
119 /* Extracts an operand value from an instruction. */
120 /* We do not perform the shift operation for larl-type address
121 operands here since that would lead to an overflow of the 32 bit
122 integer value. Instead the shift operation is done when printing
123 the operand. */
124
125 static inline union operand_value
s390_extract_operand(const bfd_byte * insn,const struct s390_operand * operand)126 s390_extract_operand (const bfd_byte *insn,
127 const struct s390_operand *operand)
128 {
129 union operand_value ret;
130 unsigned int val;
131 int bits;
132 const bfd_byte *orig_insn = insn;
133
134 /* Extract fragments of the operand byte for byte. */
135 insn += operand->shift / 8;
136 bits = (operand->shift & 7) + operand->bits;
137 val = 0;
138 do
139 {
140 val <<= 8;
141 val |= (unsigned int) *insn++;
142 bits -= 8;
143 }
144 while (bits > 0);
145 val >>= -bits;
146 val &= ((1U << (operand->bits - 1)) << 1) - 1;
147
148 /* Check for special long displacement case. */
149 if (operand->bits == 20 && operand->shift == 20)
150 val = (val & 0xff) << 12 | (val & 0xfff00) >> 8;
151
152 /* Sign extend value if the operand is signed or pc relative. Avoid
153 integer overflows. */
154 if (operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL))
155 {
156 unsigned int m = 1U << (operand->bits - 1);
157
158 if (val >= m)
159 ret.i = (int) (val - m) - 1 - (int) (m - 1U);
160 else
161 ret.i = (int) val;
162 }
163 else if (operand->flags & S390_OPERAND_LENGTH)
164 /* Length x in an instruction has real length x + 1. */
165 ret.u = val + 1;
166
167 else if (operand->flags & S390_OPERAND_VR)
168 {
169 /* Extract the extra bits for a vector register operand stored
170 in the RXB field. */
171 unsigned vr = operand->shift == 32 ? 3
172 : (unsigned) operand->shift / 4 - 2;
173
174 ret.u = val | ((orig_insn[4] & (1 << (3 - vr))) << (vr + 1));
175 }
176 else
177 ret.u = val;
178
179 return ret;
180 }
181
182 /* Print the S390 instruction in BUFFER, assuming that it matches the
183 given OPCODE. */
184
185 static void
s390_print_insn_with_opcode(bfd_vma memaddr,struct disassemble_info * info,const bfd_byte * buffer,const struct s390_opcode * opcode)186 s390_print_insn_with_opcode (bfd_vma memaddr,
187 struct disassemble_info *info,
188 const bfd_byte *buffer,
189 const struct s390_opcode *opcode)
190 {
191 const unsigned char *opindex;
192 char separator;
193
194 /* Mnemonic. */
195 info->fprintf_styled_func (info->stream, dis_style_mnemonic,
196 "%s", opcode->name);
197
198 /* Operands. */
199 separator = '\t';
200 for (opindex = opcode->operands; *opindex != 0; opindex++)
201 {
202 const struct s390_operand *operand = s390_operands + *opindex;
203 union operand_value val = s390_extract_operand (buffer, operand);
204 unsigned long flags = operand->flags;
205
206 if ((flags & S390_OPERAND_INDEX) && val.u == 0)
207 continue;
208 if ((flags & S390_OPERAND_BASE) &&
209 val.u == 0 && separator == '(')
210 {
211 separator = ',';
212 continue;
213 }
214
215 /* For instructions with a last optional operand don't print it
216 if zero. */
217 if ((opcode->flags & (S390_INSTR_FLAG_OPTPARM | S390_INSTR_FLAG_OPTPARM2))
218 && val.u == 0
219 && opindex[1] == 0)
220 break;
221
222 if ((opcode->flags & S390_INSTR_FLAG_OPTPARM2)
223 && val.u == 0 && opindex[1] != 0 && opindex[2] == 0)
224 {
225 union operand_value next_op_val =
226 s390_extract_operand (buffer, s390_operands + opindex[1]);
227 if (next_op_val.u == 0)
228 break;
229 }
230
231 if (flags & S390_OPERAND_GPR)
232 {
233 info->fprintf_styled_func (info->stream, dis_style_text,
234 "%c", separator);
235 info->fprintf_styled_func (info->stream, dis_style_register,
236 "%%r%u", val.u);
237 }
238 else if (flags & S390_OPERAND_FPR)
239 {
240 info->fprintf_styled_func (info->stream, dis_style_text,
241 "%c", separator);
242 info->fprintf_styled_func (info->stream, dis_style_register,
243 "%%f%u", val.u);
244 }
245 else if (flags & S390_OPERAND_VR)
246 {
247 info->fprintf_styled_func (info->stream, dis_style_text,
248 "%c", separator);
249 info->fprintf_styled_func (info->stream, dis_style_register,
250 "%%v%i", val.u);
251 }
252 else if (flags & S390_OPERAND_AR)
253 {
254 info->fprintf_styled_func (info->stream, dis_style_text,
255 "%c", separator);
256 info->fprintf_styled_func (info->stream, dis_style_register,
257 "%%a%u", val.u);
258 }
259 else if (flags & S390_OPERAND_CR)
260 {
261 info->fprintf_styled_func (info->stream, dis_style_text,
262 "%c", separator);
263 info->fprintf_styled_func (info->stream, dis_style_register,
264 "%%c%u", val.u);
265 }
266 else if (flags & S390_OPERAND_PCREL)
267 {
268 bfd_vma target = memaddr + val.i + val.i;
269
270 /* Provide info for jump visualization. May be evaluated by p_a_f(). */
271 info->target = target;
272
273 info->fprintf_styled_func (info->stream, dis_style_text,
274 "%c", separator);
275 info->print_address_func (target, info);
276 }
277 else if (flags & S390_OPERAND_SIGNED)
278 {
279 enum disassembler_style style;
280
281 info->fprintf_styled_func (info->stream, dis_style_text,
282 "%c", separator);
283 style = ((flags & S390_OPERAND_DISP)
284 ? dis_style_address_offset : dis_style_immediate);
285 info->fprintf_styled_func (info->stream, style, "%i", val.i);
286 }
287 else
288 {
289 enum disassembler_style style;
290
291 if (flags & S390_OPERAND_OR1)
292 val.u &= ~1;
293 if (flags & S390_OPERAND_OR2)
294 val.u &= ~2;
295 if (flags & S390_OPERAND_OR8)
296 val.u &= ~8;
297
298 if ((opcode->flags & S390_INSTR_FLAG_OPTPARM)
299 && val.u == 0
300 && opindex[1] == 0)
301 break;
302 info->fprintf_styled_func (info->stream, dis_style_text,
303 "%c", separator);
304 style = ((flags & S390_OPERAND_DISP)
305 ? dis_style_address_offset : dis_style_immediate);
306 info->fprintf_styled_func (info->stream, style, "%u", val.u);
307 }
308
309 if (flags & S390_OPERAND_DISP)
310 separator = '(';
311 else if (flags & S390_OPERAND_BASE)
312 {
313 info->fprintf_styled_func (info->stream, dis_style_text, ")");
314 separator = ',';
315 }
316 else
317 separator = ',';
318 }
319
320 /* Optional: instruction name. */
321 if (option_print_insn_desc && opcode->description
322 && opcode->description[0] != '\0')
323 info->fprintf_styled_func (info->stream, dis_style_comment_start, "\t# %s",
324 opcode->description);
325 }
326
327 /* Check whether opcode A's mask is more specific than that of B. */
328
329 static int
opcode_mask_more_specific(const struct s390_opcode * a,const struct s390_opcode * b)330 opcode_mask_more_specific (const struct s390_opcode *a,
331 const struct s390_opcode *b)
332 {
333 return (((int) a->mask[0] + a->mask[1] + a->mask[2]
334 + a->mask[3] + a->mask[4] + a->mask[5])
335 > ((int) b->mask[0] + b->mask[1] + b->mask[2]
336 + b->mask[3] + b->mask[4] + b->mask[5]));
337 }
338
339 /* Print a S390 instruction. */
340
341 int
print_insn_s390(bfd_vma memaddr,struct disassemble_info * info)342 print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
343 {
344 bfd_byte buffer[6];
345 const struct s390_opcode *opcode = NULL;
346 unsigned int value;
347 int status, opsize, bufsize, bytes_to_dump, i;
348
349 /* The output looks better if we put 6 bytes on a line. */
350 info->bytes_per_line = 6;
351
352 /* Set some defaults for the insn info. */
353 info->insn_info_valid = 0;
354 info->branch_delay_insns = 0;
355 info->data_size = 0;
356 info->insn_type = dis_nonbranch;
357 info->target = 0;
358 info->target2 = 0;
359
360 /* Every S390 instruction is max 6 bytes long. */
361 memset (buffer, 0, 6);
362 status = info->read_memory_func (memaddr, buffer, 6, info);
363 if (status != 0)
364 {
365 for (bufsize = 0; bufsize < 6; bufsize++)
366 if (info->read_memory_func (memaddr, buffer, bufsize + 1, info) != 0)
367 break;
368 if (bufsize <= 0)
369 {
370 info->memory_error_func (status, memaddr, info);
371 return -1;
372 }
373 opsize = s390_insn_length (buffer);
374 status = opsize > bufsize;
375 }
376 else
377 {
378 bufsize = 6;
379 opsize = s390_insn_length (buffer);
380 }
381
382 if (status == 0)
383 {
384 const struct s390_opcode *op;
385
386 /* Find the "best match" in the opcode table. */
387 for (op = s390_opcodes + opc_index[buffer[0]];
388 op != s390_opcodes + s390_num_opcodes
389 && op->opcode[0] == buffer[0];
390 op++)
391 {
392 if ((op->modes & current_arch_mask)
393 && s390_insn_matches_opcode (buffer, op)
394 && (opcode == NULL
395 || opcode_mask_more_specific (op, opcode)))
396 opcode = op;
397 }
398
399 if (opcode != NULL)
400 {
401 /* Provide info for jump visualization. Must be done before print. */
402 switch (opcode->flags & S390_INSTR_FLAG_CLASS_MASK)
403 {
404 case S390_INSTR_FLAGS_CLASS_JUMP:
405 info->insn_type = dis_branch;
406 break;
407 case S390_INSTR_FLAGS_CLASS_CONDJUMP:
408 info->insn_type = dis_condbranch;
409 break;
410 case S390_INSTR_FLAGS_CLASS_JUMPSR:
411 info->insn_type = dis_jsr;
412 break;
413 default:
414 info->insn_type = dis_nonbranch;
415 }
416 info->insn_info_valid = 1;
417
418 /* The instruction is valid. Print it and return its size. */
419 s390_print_insn_with_opcode (memaddr, info, buffer, opcode);
420 return opsize;
421 }
422 }
423
424 /* For code sections it makes sense to skip unknown instructions
425 according to their length bits. */
426 if (status == 0
427 && option_use_insn_len_bits_p
428 && info->section != NULL
429 && (info->section->flags & SEC_CODE))
430 bytes_to_dump = opsize;
431 else
432 /* By default unknown instructions are printed as .long's/.short'
433 depending on how many bytes are available. */
434 bytes_to_dump = bufsize >= 4 ? 4 : bufsize;
435
436 if (bytes_to_dump == 0)
437 return 0;
438
439 info->insn_type = dis_noninsn;
440 info->insn_info_valid = 1;
441
442 /* Fall back to hex print. */
443 switch (bytes_to_dump)
444 {
445 case 4:
446 value = (unsigned int) buffer[0];
447 value = (value << 8) + (unsigned int) buffer[1];
448 value = (value << 8) + (unsigned int) buffer[2];
449 value = (value << 8) + (unsigned int) buffer[3];
450 info->fprintf_styled_func (info->stream, dis_style_assembler_directive,
451 ".long");
452 info->fprintf_styled_func (info->stream, dis_style_text,
453 "\t");
454 info->fprintf_styled_func (info->stream, dis_style_immediate,
455 "0x%08x", value);
456 return 4;
457 case 2:
458 value = (unsigned int) buffer[0];
459 value = (value << 8) + (unsigned int) buffer[1];
460 info->fprintf_styled_func (info->stream, dis_style_assembler_directive,
461 ".short");
462 info->fprintf_styled_func (info->stream, dis_style_text,
463 "\t");
464 info->fprintf_styled_func (info->stream, dis_style_immediate,
465 "0x%04x", value);
466 return 2;
467 default:
468 info->fprintf_styled_func (info->stream, dis_style_assembler_directive,
469 ".byte");
470 info->fprintf_styled_func (info->stream, dis_style_text,
471 "\t");
472 info->fprintf_styled_func (info->stream, dis_style_immediate,
473 "0x%02x", (unsigned int) buffer[0]);
474 for (i = 1; i < bytes_to_dump; i++)
475 info->fprintf_styled_func (info->stream, dis_style_immediate,
476 "0x%02x", (unsigned int) buffer[i]);
477 return bytes_to_dump;
478 }
479 return 0;
480 }
481
482 const disasm_options_and_args_t *
disassembler_options_s390(void)483 disassembler_options_s390 (void)
484 {
485 static disasm_options_and_args_t *opts_and_args;
486
487 if (opts_and_args == NULL)
488 {
489 size_t i, num_options = ARRAY_SIZE (options);
490 disasm_options_t *opts;
491
492 opts_and_args = XNEW (disasm_options_and_args_t);
493 opts_and_args->args = NULL;
494
495 opts = &opts_and_args->options;
496 opts->name = XNEWVEC (const char *, num_options + 1);
497 opts->description = XNEWVEC (const char *, num_options + 1);
498 opts->arg = NULL;
499 for (i = 0; i < num_options; i++)
500 {
501 opts->name[i] = options[i].name;
502 opts->description[i] = _(options[i].description);
503 }
504 /* The array we return must be NULL terminated. */
505 opts->name[i] = NULL;
506 opts->description[i] = NULL;
507 }
508
509 return opts_and_args;
510 }
511
512 void
print_s390_disassembler_options(FILE * stream)513 print_s390_disassembler_options (FILE *stream)
514 {
515 unsigned int i, max_len = 0;
516 fprintf (stream, _("\n\
517 The following S/390 specific disassembler options are supported for use\n\
518 with the -M switch (multiple options should be separated by commas):\n"));
519
520 for (i = 0; i < ARRAY_SIZE (options); i++)
521 {
522 unsigned int len = strlen (options[i].name);
523 if (max_len < len)
524 max_len = len;
525 }
526
527 for (i = 0, max_len++; i < ARRAY_SIZE (options); i++)
528 fprintf (stream, " %s%*c %s\n",
529 options[i].name,
530 (int)(max_len - strlen (options[i].name)), ' ',
531 _(options[i].description));
532 }
533