| 1 | /* s390-dis.c -- Disassemble S390 instructions |
| 2 | Copyright (C) 2000-2017 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 | |
| 30 | static int opc_index[256]; |
| 31 | static int current_arch_mask = 0; |
| 32 | static int option_use_insn_len_bits_p = 0; |
| 33 | |
| 34 | typedef struct |
| 35 | { |
| 36 | const char *name; |
| 37 | const char *description; |
| 38 | } s390_options_t; |
| 39 | |
| 40 | static const s390_options_t options[] = |
| 41 | { |
| 42 | { "esa" , N_("Disassemble in ESA architecture mode") }, |
| 43 | { "zarch", N_("Disassemble in z/Architecture mode") }, |
| 44 | { "insnlength", N_("Print unknown instructions according to " |
| 45 | "length from first two bits") } |
| 46 | }; |
| 47 | |
| 48 | /* Set up index table for first opcode byte. */ |
| 49 | |
| 50 | void |
| 51 | disassemble_init_s390 (struct disassemble_info *info) |
| 52 | { |
| 53 | int i; |
| 54 | const char *p; |
| 55 | |
| 56 | memset (opc_index, 0, sizeof (opc_index)); |
| 57 | |
| 58 | /* Reverse order, such that each opc_index ends up pointing to the |
| 59 | first matching entry instead of the last. */ |
| 60 | for (i = s390_num_opcodes; i--; ) |
| 61 | opc_index[s390_opcodes[i].opcode[0]] = i; |
| 62 | |
| 63 | current_arch_mask = 1 << S390_OPCODE_ZARCH; |
| 64 | option_use_insn_len_bits_p = 0; |
| 65 | |
| 66 | for (p = info->disassembler_options; p != NULL; ) |
| 67 | { |
| 68 | if (CONST_STRNEQ (p, "esa")) |
| 69 | current_arch_mask = 1 << S390_OPCODE_ESA; |
| 70 | else if (CONST_STRNEQ (p, "zarch")) |
| 71 | current_arch_mask = 1 << S390_OPCODE_ZARCH; |
| 72 | else if (CONST_STRNEQ (p, "insnlength")) |
| 73 | option_use_insn_len_bits_p = 1; |
| 74 | else |
| 75 | fprintf (stderr, "Unknown S/390 disassembler option: %s\n", p); |
| 76 | |
| 77 | p = strchr (p, ','); |
| 78 | if (p != NULL) |
| 79 | p++; |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | /* Derive the length of an instruction from its first byte. */ |
| 84 | |
| 85 | static inline int |
| 86 | s390_insn_length (const bfd_byte *buffer) |
| 87 | { |
| 88 | /* 00xxxxxx -> 2, 01xxxxxx/10xxxxxx -> 4, 11xxxxxx -> 6. */ |
| 89 | return ((buffer[0] >> 6) + 3) & ~1U; |
| 90 | } |
| 91 | |
| 92 | /* Match the instruction in BUFFER against the given OPCODE, excluding |
| 93 | the first byte. */ |
| 94 | |
| 95 | static inline int |
| 96 | s390_insn_matches_opcode (const bfd_byte *buffer, |
| 97 | const struct s390_opcode *opcode) |
| 98 | { |
| 99 | return (buffer[1] & opcode->mask[1]) == opcode->opcode[1] |
| 100 | && (buffer[2] & opcode->mask[2]) == opcode->opcode[2] |
| 101 | && (buffer[3] & opcode->mask[3]) == opcode->opcode[3] |
| 102 | && (buffer[4] & opcode->mask[4]) == opcode->opcode[4] |
| 103 | && (buffer[5] & opcode->mask[5]) == opcode->opcode[5]; |
| 104 | } |
| 105 | |
| 106 | union operand_value |
| 107 | { |
| 108 | int i; |
| 109 | unsigned int u; |
| 110 | }; |
| 111 | |
| 112 | /* Extracts an operand value from an instruction. */ |
| 113 | /* We do not perform the shift operation for larl-type address |
| 114 | operands here since that would lead to an overflow of the 32 bit |
| 115 | integer value. Instead the shift operation is done when printing |
| 116 | the operand. */ |
| 117 | |
| 118 | static inline union operand_value |
| 119 | s390_extract_operand (const bfd_byte *insn, |
| 120 | const struct s390_operand *operand) |
| 121 | { |
| 122 | union operand_value ret; |
| 123 | unsigned int val; |
| 124 | int bits; |
| 125 | const bfd_byte *orig_insn = insn; |
| 126 | |
| 127 | /* Extract fragments of the operand byte for byte. */ |
| 128 | insn += operand->shift / 8; |
| 129 | bits = (operand->shift & 7) + operand->bits; |
| 130 | val = 0; |
| 131 | do |
| 132 | { |
| 133 | val <<= 8; |
| 134 | val |= (unsigned int) *insn++; |
| 135 | bits -= 8; |
| 136 | } |
| 137 | while (bits > 0); |
| 138 | val >>= -bits; |
| 139 | val &= ((1U << (operand->bits - 1)) << 1) - 1; |
| 140 | |
| 141 | /* Check for special long displacement case. */ |
| 142 | if (operand->bits == 20 && operand->shift == 20) |
| 143 | val = (val & 0xff) << 12 | (val & 0xfff00) >> 8; |
| 144 | |
| 145 | /* Sign extend value if the operand is signed or pc relative. Avoid |
| 146 | integer overflows. */ |
| 147 | if (operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL)) |
| 148 | { |
| 149 | unsigned int m = 1U << (operand->bits - 1); |
| 150 | |
| 151 | if (val >= m) |
| 152 | ret.i = (int) (val - m) - 1 - (int) (m - 1U); |
| 153 | else |
| 154 | ret.i = (int) val; |
| 155 | } |
| 156 | else if (operand->flags & S390_OPERAND_LENGTH) |
| 157 | /* Length x in an instruction has real length x + 1. */ |
| 158 | ret.u = val + 1; |
| 159 | |
| 160 | else if (operand->flags & S390_OPERAND_VR) |
| 161 | { |
| 162 | /* Extract the extra bits for a vector register operand stored |
| 163 | in the RXB field. */ |
| 164 | unsigned vr = operand->shift == 32 ? 3 |
| 165 | : (unsigned) operand->shift / 4 - 2; |
| 166 | |
| 167 | ret.u = val | ((orig_insn[4] & (1 << (3 - vr))) << (vr + 1)); |
| 168 | } |
| 169 | else |
| 170 | ret.u = val; |
| 171 | |
| 172 | return ret; |
| 173 | } |
| 174 | |
| 175 | /* Print the S390 instruction in BUFFER, assuming that it matches the |
| 176 | given OPCODE. */ |
| 177 | |
| 178 | static void |
| 179 | s390_print_insn_with_opcode (bfd_vma memaddr, |
| 180 | struct disassemble_info *info, |
| 181 | const bfd_byte *buffer, |
| 182 | const struct s390_opcode *opcode) |
| 183 | { |
| 184 | const unsigned char *opindex; |
| 185 | char separator; |
| 186 | |
| 187 | /* Mnemonic. */ |
| 188 | info->fprintf_func (info->stream, "%s", opcode->name); |
| 189 | |
| 190 | /* Operands. */ |
| 191 | separator = '\t'; |
| 192 | for (opindex = opcode->operands; *opindex != 0; opindex++) |
| 193 | { |
| 194 | const struct s390_operand *operand = s390_operands + *opindex; |
| 195 | union operand_value val = s390_extract_operand (buffer, operand); |
| 196 | unsigned long flags = operand->flags; |
| 197 | |
| 198 | if ((flags & S390_OPERAND_INDEX) && val.u == 0) |
| 199 | continue; |
| 200 | if ((flags & S390_OPERAND_BASE) && |
| 201 | val.u == 0 && separator == '(') |
| 202 | { |
| 203 | separator = ','; |
| 204 | continue; |
| 205 | } |
| 206 | |
| 207 | /* For instructions with a last optional operand don't print it |
| 208 | if zero. */ |
| 209 | if ((opcode->flags & (S390_INSTR_FLAG_OPTPARM | S390_INSTR_FLAG_OPTPARM2)) |
| 210 | && val.u == 0 |
| 211 | && opindex[1] == 0) |
| 212 | break; |
| 213 | |
| 214 | if ((opcode->flags & S390_INSTR_FLAG_OPTPARM2) |
| 215 | && val.u == 0 && opindex[1] != 0 && opindex[2] == 0) |
| 216 | { |
| 217 | union operand_value next_op_val = |
| 218 | s390_extract_operand (buffer, s390_operands + opindex[1]); |
| 219 | if (next_op_val.u == 0) |
| 220 | break; |
| 221 | } |
| 222 | |
| 223 | if (flags & S390_OPERAND_GPR) |
| 224 | info->fprintf_func (info->stream, "%c%%r%u", separator, val.u); |
| 225 | else if (flags & S390_OPERAND_FPR) |
| 226 | info->fprintf_func (info->stream, "%c%%f%u", separator, val.u); |
| 227 | else if (flags & S390_OPERAND_VR) |
| 228 | info->fprintf_func (info->stream, "%c%%v%i", separator, val.u); |
| 229 | else if (flags & S390_OPERAND_AR) |
| 230 | info->fprintf_func (info->stream, "%c%%a%u", separator, val.u); |
| 231 | else if (flags & S390_OPERAND_CR) |
| 232 | info->fprintf_func (info->stream, "%c%%c%u", separator, val.u); |
| 233 | else if (flags & S390_OPERAND_PCREL) |
| 234 | { |
| 235 | info->fprintf_func (info->stream, "%c", separator); |
| 236 | info->print_address_func (memaddr + val.i + val.i, info); |
| 237 | } |
| 238 | else if (flags & S390_OPERAND_SIGNED) |
| 239 | info->fprintf_func (info->stream, "%c%i", separator, val.i); |
| 240 | else |
| 241 | { |
| 242 | if (flags & S390_OPERAND_OR1) |
| 243 | val.u &= ~1; |
| 244 | if (flags & S390_OPERAND_OR2) |
| 245 | val.u &= ~2; |
| 246 | if (flags & S390_OPERAND_OR8) |
| 247 | val.u &= ~8; |
| 248 | |
| 249 | if ((opcode->flags & S390_INSTR_FLAG_OPTPARM) |
| 250 | && val.u == 0 |
| 251 | && opindex[1] == 0) |
| 252 | break; |
| 253 | info->fprintf_func (info->stream, "%c%u", separator, val.u); |
| 254 | } |
| 255 | |
| 256 | if (flags & S390_OPERAND_DISP) |
| 257 | separator = '('; |
| 258 | else if (flags & S390_OPERAND_BASE) |
| 259 | { |
| 260 | info->fprintf_func (info->stream, ")"); |
| 261 | separator = ','; |
| 262 | } |
| 263 | else |
| 264 | separator = ','; |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | /* Check whether opcode A's mask is more specific than that of B. */ |
| 269 | |
| 270 | static int |
| 271 | opcode_mask_more_specific (const struct s390_opcode *a, |
| 272 | const struct s390_opcode *b) |
| 273 | { |
| 274 | return (((int) a->mask[0] + a->mask[1] + a->mask[2] |
| 275 | + a->mask[3] + a->mask[4] + a->mask[5]) |
| 276 | > ((int) b->mask[0] + b->mask[1] + b->mask[2] |
| 277 | + b->mask[3] + b->mask[4] + b->mask[5])); |
| 278 | } |
| 279 | |
| 280 | /* Print a S390 instruction. */ |
| 281 | |
| 282 | int |
| 283 | print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info) |
| 284 | { |
| 285 | bfd_byte buffer[6]; |
| 286 | const struct s390_opcode *opcode = NULL; |
| 287 | unsigned int value; |
| 288 | int status, opsize, bufsize, bytes_to_dump, i; |
| 289 | |
| 290 | /* The output looks better if we put 6 bytes on a line. */ |
| 291 | info->bytes_per_line = 6; |
| 292 | |
| 293 | /* Every S390 instruction is max 6 bytes long. */ |
| 294 | memset (buffer, 0, 6); |
| 295 | status = info->read_memory_func (memaddr, buffer, 6, info); |
| 296 | if (status != 0) |
| 297 | { |
| 298 | for (bufsize = 0; bufsize < 6; bufsize++) |
| 299 | if (info->read_memory_func (memaddr, buffer, bufsize + 1, info) != 0) |
| 300 | break; |
| 301 | if (bufsize <= 0) |
| 302 | { |
| 303 | info->memory_error_func (status, memaddr, info); |
| 304 | return -1; |
| 305 | } |
| 306 | opsize = s390_insn_length (buffer); |
| 307 | status = opsize > bufsize; |
| 308 | } |
| 309 | else |
| 310 | { |
| 311 | bufsize = 6; |
| 312 | opsize = s390_insn_length (buffer); |
| 313 | } |
| 314 | |
| 315 | if (status == 0) |
| 316 | { |
| 317 | const struct s390_opcode *op; |
| 318 | |
| 319 | /* Find the "best match" in the opcode table. */ |
| 320 | for (op = s390_opcodes + opc_index[buffer[0]]; |
| 321 | op != s390_opcodes + s390_num_opcodes |
| 322 | && op->opcode[0] == buffer[0]; |
| 323 | op++) |
| 324 | { |
| 325 | if ((op->modes & current_arch_mask) |
| 326 | && s390_insn_matches_opcode (buffer, op) |
| 327 | && (opcode == NULL |
| 328 | || opcode_mask_more_specific (op, opcode))) |
| 329 | opcode = op; |
| 330 | } |
| 331 | |
| 332 | if (opcode != NULL) |
| 333 | { |
| 334 | /* The instruction is valid. Print it and return its size. */ |
| 335 | s390_print_insn_with_opcode (memaddr, info, buffer, opcode); |
| 336 | return opsize; |
| 337 | } |
| 338 | } |
| 339 | |
| 340 | /* For code sections it makes sense to skip unknown instructions |
| 341 | according to their length bits. */ |
| 342 | if (status == 0 |
| 343 | && option_use_insn_len_bits_p |
| 344 | && info->section != NULL |
| 345 | && (info->section->flags & SEC_CODE)) |
| 346 | bytes_to_dump = opsize; |
| 347 | else |
| 348 | /* By default unknown instructions are printed as .long's/.short' |
| 349 | depending on how many bytes are available. */ |
| 350 | bytes_to_dump = bufsize >= 4 ? 4 : bufsize; |
| 351 | |
| 352 | if (bytes_to_dump == 0) |
| 353 | return 0; |
| 354 | |
| 355 | /* Fall back to hex print. */ |
| 356 | switch (bytes_to_dump) |
| 357 | { |
| 358 | case 4: |
| 359 | value = (unsigned int) buffer[0]; |
| 360 | value = (value << 8) + (unsigned int) buffer[1]; |
| 361 | value = (value << 8) + (unsigned int) buffer[2]; |
| 362 | value = (value << 8) + (unsigned int) buffer[3]; |
| 363 | info->fprintf_func (info->stream, ".long\t0x%08x", value); |
| 364 | return 4; |
| 365 | case 2: |
| 366 | value = (unsigned int) buffer[0]; |
| 367 | value = (value << 8) + (unsigned int) buffer[1]; |
| 368 | info->fprintf_func (info->stream, ".short\t0x%04x", value); |
| 369 | return 2; |
| 370 | default: |
| 371 | info->fprintf_func (info->stream, ".byte\t0x%02x", |
| 372 | (unsigned int) buffer[0]); |
| 373 | for (i = 1; i < bytes_to_dump; i++) |
| 374 | info->fprintf_func (info->stream, ",0x%02x", |
| 375 | (unsigned int) buffer[i]); |
| 376 | return bytes_to_dump; |
| 377 | } |
| 378 | return 0; |
| 379 | } |
| 380 | |
| 381 | const disasm_options_t * |
| 382 | disassembler_options_s390 (void) |
| 383 | { |
| 384 | static disasm_options_t *opts = NULL; |
| 385 | |
| 386 | if (opts == NULL) |
| 387 | { |
| 388 | size_t i, num_options = ARRAY_SIZE (options); |
| 389 | opts = XNEW (disasm_options_t); |
| 390 | opts->name = XNEWVEC (const char *, num_options + 1); |
| 391 | opts->description = XNEWVEC (const char *, num_options + 1); |
| 392 | for (i = 0; i < num_options; i++) |
| 393 | { |
| 394 | opts->name[i] = options[i].name; |
| 395 | opts->description[i] = _(options[i].description); |
| 396 | } |
| 397 | /* The array we return must be NULL terminated. */ |
| 398 | opts->name[i] = NULL; |
| 399 | opts->description[i] = NULL; |
| 400 | } |
| 401 | |
| 402 | return opts; |
| 403 | } |
| 404 | |
| 405 | void |
| 406 | print_s390_disassembler_options (FILE *stream) |
| 407 | { |
| 408 | unsigned int i, max_len = 0; |
| 409 | fprintf (stream, _("\n\ |
| 410 | The following S/390 specific disassembler options are supported for use\n\ |
| 411 | with the -M switch (multiple options should be separated by commas):\n")); |
| 412 | |
| 413 | for (i = 0; i < ARRAY_SIZE (options); i++) |
| 414 | { |
| 415 | unsigned int len = strlen (options[i].name); |
| 416 | if (max_len < len) |
| 417 | max_len = len; |
| 418 | } |
| 419 | |
| 420 | for (i = 0, max_len++; i < ARRAY_SIZE (options); i++) |
| 421 | fprintf (stream, " %s%*c %s\n", |
| 422 | options[i].name, |
| 423 | (int)(max_len - strlen (options[i].name)), ' ', |
| 424 | _(options[i].description)); |
| 425 | } |