1 /* s390-dis.c -- Disassemble S390 instructions 2 Copyright (C) 2000-2020 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 /* xgettext:c-format */ 76 opcodes_error_handler (_("unknown S/390 disassembler option: %s"), p); 77 78 p = strchr (p, ','); 79 if (p != NULL) 80 p++; 81 } 82 } 83 84 /* Derive the length of an instruction from its first byte. */ 85 86 static inline int 87 s390_insn_length (const bfd_byte *buffer) 88 { 89 /* 00xxxxxx -> 2, 01xxxxxx/10xxxxxx -> 4, 11xxxxxx -> 6. */ 90 return ((buffer[0] >> 6) + 3) & ~1U; 91 } 92 93 /* Match the instruction in BUFFER against the given OPCODE, excluding 94 the first byte. */ 95 96 static inline int 97 s390_insn_matches_opcode (const bfd_byte *buffer, 98 const struct s390_opcode *opcode) 99 { 100 return (buffer[1] & opcode->mask[1]) == opcode->opcode[1] 101 && (buffer[2] & opcode->mask[2]) == opcode->opcode[2] 102 && (buffer[3] & opcode->mask[3]) == opcode->opcode[3] 103 && (buffer[4] & opcode->mask[4]) == opcode->opcode[4] 104 && (buffer[5] & opcode->mask[5]) == opcode->opcode[5]; 105 } 106 107 union operand_value 108 { 109 int i; 110 unsigned int u; 111 }; 112 113 /* Extracts an operand value from an instruction. */ 114 /* We do not perform the shift operation for larl-type address 115 operands here since that would lead to an overflow of the 32 bit 116 integer value. Instead the shift operation is done when printing 117 the operand. */ 118 119 static inline union operand_value 120 s390_extract_operand (const bfd_byte *insn, 121 const struct s390_operand *operand) 122 { 123 union operand_value ret; 124 unsigned int val; 125 int bits; 126 const bfd_byte *orig_insn = insn; 127 128 /* Extract fragments of the operand byte for byte. */ 129 insn += operand->shift / 8; 130 bits = (operand->shift & 7) + operand->bits; 131 val = 0; 132 do 133 { 134 val <<= 8; 135 val |= (unsigned int) *insn++; 136 bits -= 8; 137 } 138 while (bits > 0); 139 val >>= -bits; 140 val &= ((1U << (operand->bits - 1)) << 1) - 1; 141 142 /* Check for special long displacement case. */ 143 if (operand->bits == 20 && operand->shift == 20) 144 val = (val & 0xff) << 12 | (val & 0xfff00) >> 8; 145 146 /* Sign extend value if the operand is signed or pc relative. Avoid 147 integer overflows. */ 148 if (operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL)) 149 { 150 unsigned int m = 1U << (operand->bits - 1); 151 152 if (val >= m) 153 ret.i = (int) (val - m) - 1 - (int) (m - 1U); 154 else 155 ret.i = (int) val; 156 } 157 else if (operand->flags & S390_OPERAND_LENGTH) 158 /* Length x in an instruction has real length x + 1. */ 159 ret.u = val + 1; 160 161 else if (operand->flags & S390_OPERAND_VR) 162 { 163 /* Extract the extra bits for a vector register operand stored 164 in the RXB field. */ 165 unsigned vr = operand->shift == 32 ? 3 166 : (unsigned) operand->shift / 4 - 2; 167 168 ret.u = val | ((orig_insn[4] & (1 << (3 - vr))) << (vr + 1)); 169 } 170 else 171 ret.u = val; 172 173 return ret; 174 } 175 176 /* Print the S390 instruction in BUFFER, assuming that it matches the 177 given OPCODE. */ 178 179 static void 180 s390_print_insn_with_opcode (bfd_vma memaddr, 181 struct disassemble_info *info, 182 const bfd_byte *buffer, 183 const struct s390_opcode *opcode) 184 { 185 const unsigned char *opindex; 186 char separator; 187 188 /* Mnemonic. */ 189 info->fprintf_func (info->stream, "%s", opcode->name); 190 191 /* Operands. */ 192 separator = '\t'; 193 for (opindex = opcode->operands; *opindex != 0; opindex++) 194 { 195 const struct s390_operand *operand = s390_operands + *opindex; 196 union operand_value val = s390_extract_operand (buffer, operand); 197 unsigned long flags = operand->flags; 198 199 if ((flags & S390_OPERAND_INDEX) && val.u == 0) 200 continue; 201 if ((flags & S390_OPERAND_BASE) && 202 val.u == 0 && separator == '(') 203 { 204 separator = ','; 205 continue; 206 } 207 208 /* For instructions with a last optional operand don't print it 209 if zero. */ 210 if ((opcode->flags & (S390_INSTR_FLAG_OPTPARM | S390_INSTR_FLAG_OPTPARM2)) 211 && val.u == 0 212 && opindex[1] == 0) 213 break; 214 215 if ((opcode->flags & S390_INSTR_FLAG_OPTPARM2) 216 && val.u == 0 && opindex[1] != 0 && opindex[2] == 0) 217 { 218 union operand_value next_op_val = 219 s390_extract_operand (buffer, s390_operands + opindex[1]); 220 if (next_op_val.u == 0) 221 break; 222 } 223 224 if (flags & S390_OPERAND_GPR) 225 info->fprintf_func (info->stream, "%c%%r%u", separator, val.u); 226 else if (flags & S390_OPERAND_FPR) 227 info->fprintf_func (info->stream, "%c%%f%u", separator, val.u); 228 else if (flags & S390_OPERAND_VR) 229 info->fprintf_func (info->stream, "%c%%v%i", separator, val.u); 230 else if (flags & S390_OPERAND_AR) 231 info->fprintf_func (info->stream, "%c%%a%u", separator, val.u); 232 else if (flags & S390_OPERAND_CR) 233 info->fprintf_func (info->stream, "%c%%c%u", separator, val.u); 234 else if (flags & S390_OPERAND_PCREL) 235 { 236 info->fprintf_func (info->stream, "%c", separator); 237 info->print_address_func (memaddr + val.i + val.i, info); 238 } 239 else if (flags & S390_OPERAND_SIGNED) 240 info->fprintf_func (info->stream, "%c%i", separator, val.i); 241 else 242 { 243 if (flags & S390_OPERAND_OR1) 244 val.u &= ~1; 245 if (flags & S390_OPERAND_OR2) 246 val.u &= ~2; 247 if (flags & S390_OPERAND_OR8) 248 val.u &= ~8; 249 250 if ((opcode->flags & S390_INSTR_FLAG_OPTPARM) 251 && val.u == 0 252 && opindex[1] == 0) 253 break; 254 info->fprintf_func (info->stream, "%c%u", separator, val.u); 255 } 256 257 if (flags & S390_OPERAND_DISP) 258 separator = '('; 259 else if (flags & S390_OPERAND_BASE) 260 { 261 info->fprintf_func (info->stream, ")"); 262 separator = ','; 263 } 264 else 265 separator = ','; 266 } 267 } 268 269 /* Check whether opcode A's mask is more specific than that of B. */ 270 271 static int 272 opcode_mask_more_specific (const struct s390_opcode *a, 273 const struct s390_opcode *b) 274 { 275 return (((int) a->mask[0] + a->mask[1] + a->mask[2] 276 + a->mask[3] + a->mask[4] + a->mask[5]) 277 > ((int) b->mask[0] + b->mask[1] + b->mask[2] 278 + b->mask[3] + b->mask[4] + b->mask[5])); 279 } 280 281 /* Print a S390 instruction. */ 282 283 int 284 print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info) 285 { 286 bfd_byte buffer[6]; 287 const struct s390_opcode *opcode = NULL; 288 unsigned int value; 289 int status, opsize, bufsize, bytes_to_dump, i; 290 291 /* The output looks better if we put 6 bytes on a line. */ 292 info->bytes_per_line = 6; 293 294 /* Every S390 instruction is max 6 bytes long. */ 295 memset (buffer, 0, 6); 296 status = info->read_memory_func (memaddr, buffer, 6, info); 297 if (status != 0) 298 { 299 for (bufsize = 0; bufsize < 6; bufsize++) 300 if (info->read_memory_func (memaddr, buffer, bufsize + 1, info) != 0) 301 break; 302 if (bufsize <= 0) 303 { 304 info->memory_error_func (status, memaddr, info); 305 return -1; 306 } 307 opsize = s390_insn_length (buffer); 308 status = opsize > bufsize; 309 } 310 else 311 { 312 bufsize = 6; 313 opsize = s390_insn_length (buffer); 314 } 315 316 if (status == 0) 317 { 318 const struct s390_opcode *op; 319 320 /* Find the "best match" in the opcode table. */ 321 for (op = s390_opcodes + opc_index[buffer[0]]; 322 op != s390_opcodes + s390_num_opcodes 323 && op->opcode[0] == buffer[0]; 324 op++) 325 { 326 if ((op->modes & current_arch_mask) 327 && s390_insn_matches_opcode (buffer, op) 328 && (opcode == NULL 329 || opcode_mask_more_specific (op, opcode))) 330 opcode = op; 331 } 332 333 if (opcode != NULL) 334 { 335 /* The instruction is valid. Print it and return its size. */ 336 s390_print_insn_with_opcode (memaddr, info, buffer, opcode); 337 return opsize; 338 } 339 } 340 341 /* For code sections it makes sense to skip unknown instructions 342 according to their length bits. */ 343 if (status == 0 344 && option_use_insn_len_bits_p 345 && info->section != NULL 346 && (info->section->flags & SEC_CODE)) 347 bytes_to_dump = opsize; 348 else 349 /* By default unknown instructions are printed as .long's/.short' 350 depending on how many bytes are available. */ 351 bytes_to_dump = bufsize >= 4 ? 4 : bufsize; 352 353 if (bytes_to_dump == 0) 354 return 0; 355 356 /* Fall back to hex print. */ 357 switch (bytes_to_dump) 358 { 359 case 4: 360 value = (unsigned int) buffer[0]; 361 value = (value << 8) + (unsigned int) buffer[1]; 362 value = (value << 8) + (unsigned int) buffer[2]; 363 value = (value << 8) + (unsigned int) buffer[3]; 364 info->fprintf_func (info->stream, ".long\t0x%08x", value); 365 return 4; 366 case 2: 367 value = (unsigned int) buffer[0]; 368 value = (value << 8) + (unsigned int) buffer[1]; 369 info->fprintf_func (info->stream, ".short\t0x%04x", value); 370 return 2; 371 default: 372 info->fprintf_func (info->stream, ".byte\t0x%02x", 373 (unsigned int) buffer[0]); 374 for (i = 1; i < bytes_to_dump; i++) 375 info->fprintf_func (info->stream, ",0x%02x", 376 (unsigned int) buffer[i]); 377 return bytes_to_dump; 378 } 379 return 0; 380 } 381 382 const disasm_options_and_args_t * 383 disassembler_options_s390 (void) 384 { 385 static disasm_options_and_args_t *opts_and_args; 386 387 if (opts_and_args == NULL) 388 { 389 size_t i, num_options = ARRAY_SIZE (options); 390 disasm_options_t *opts; 391 392 opts_and_args = XNEW (disasm_options_and_args_t); 393 opts_and_args->args = NULL; 394 395 opts = &opts_and_args->options; 396 opts->name = XNEWVEC (const char *, num_options + 1); 397 opts->description = XNEWVEC (const char *, num_options + 1); 398 opts->arg = NULL; 399 for (i = 0; i < num_options; i++) 400 { 401 opts->name[i] = options[i].name; 402 opts->description[i] = _(options[i].description); 403 } 404 /* The array we return must be NULL terminated. */ 405 opts->name[i] = NULL; 406 opts->description[i] = NULL; 407 } 408 409 return opts_and_args; 410 } 411 412 void 413 print_s390_disassembler_options (FILE *stream) 414 { 415 unsigned int i, max_len = 0; 416 fprintf (stream, _("\n\ 417 The following S/390 specific disassembler options are supported for use\n\ 418 with the -M switch (multiple options should be separated by commas):\n")); 419 420 for (i = 0; i < ARRAY_SIZE (options); i++) 421 { 422 unsigned int len = strlen (options[i].name); 423 if (max_len < len) 424 max_len = len; 425 } 426 427 for (i = 0, max_len++; i < ARRAY_SIZE (options); i++) 428 fprintf (stream, " %s%*c %s\n", 429 options[i].name, 430 (int)(max_len - strlen (options[i].name)), ' ', 431 _(options[i].description)); 432 } 433