1 /* s390-dis.c -- Disassemble S390 instructions 2 Copyright (C) 2000-2014 Free Software Foundation, Inc. 3 Contributed by Martin Schwidefsky (schwidefsky (at) 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 "dis-asm.h" 26 #include "opintl.h" 27 #include "opcode/s390.h" 28 29 static int init_flag = 0; 30 static int opc_index[256]; 31 static int current_arch_mask = 0; 32 33 /* Set up index table for first opcode byte. */ 34 35 static void 36 init_disasm (struct disassemble_info *info) 37 { 38 int i; 39 const char *p; 40 41 memset (opc_index, 0, sizeof (opc_index)); 42 43 /* Reverse order, such that each opc_index ends up pointing to the 44 first matching entry instead of the last. */ 45 for (i = s390_num_opcodes; i--; ) 46 opc_index[s390_opcodes[i].opcode[0]] = i; 47 48 for (p = info->disassembler_options; p != NULL; ) 49 { 50 if (CONST_STRNEQ (p, "esa")) 51 current_arch_mask = 1 << S390_OPCODE_ESA; 52 else if (CONST_STRNEQ (p, "zarch")) 53 current_arch_mask = 1 << S390_OPCODE_ZARCH; 54 else 55 fprintf (stderr, "Unknown S/390 disassembler option: %s\n", p); 56 57 p = strchr (p, ','); 58 if (p != NULL) 59 p++; 60 } 61 62 if (!current_arch_mask) 63 current_arch_mask = 1 << S390_OPCODE_ZARCH; 64 65 init_flag = 1; 66 } 67 68 /* Derive the length of an instruction from its first byte. */ 69 70 static inline int 71 s390_insn_length (const bfd_byte *buffer) 72 { 73 /* 00xxxxxx -> 2, 01xxxxxx/10xxxxxx -> 4, 11xxxxxx -> 6. */ 74 return ((buffer[0] >> 6) + 3) & ~1U; 75 } 76 77 /* Match the instruction in BUFFER against the given OPCODE, excluding 78 the first byte. */ 79 80 static inline int 81 s390_insn_matches_opcode (const bfd_byte *buffer, 82 const struct s390_opcode *opcode) 83 { 84 return (buffer[1] & opcode->mask[1]) == opcode->opcode[1] 85 && (buffer[2] & opcode->mask[2]) == opcode->opcode[2] 86 && (buffer[3] & opcode->mask[3]) == opcode->opcode[3] 87 && (buffer[4] & opcode->mask[4]) == opcode->opcode[4] 88 && (buffer[5] & opcode->mask[5]) == opcode->opcode[5]; 89 } 90 91 union operand_value 92 { 93 int i; 94 unsigned int u; 95 }; 96 97 /* Extracts an operand value from an instruction. */ 98 /* We do not perform the shift operation for larl-type address 99 operands here since that would lead to an overflow of the 32 bit 100 integer value. Instead the shift operation is done when printing 101 the operand. */ 102 103 static inline union operand_value 104 s390_extract_operand (const bfd_byte *insn, 105 const struct s390_operand *operand) 106 { 107 union operand_value ret; 108 unsigned int val; 109 int bits; 110 111 /* Extract fragments of the operand byte for byte. */ 112 insn += operand->shift / 8; 113 bits = (operand->shift & 7) + operand->bits; 114 val = 0; 115 do 116 { 117 val <<= 8; 118 val |= (unsigned int) *insn++; 119 bits -= 8; 120 } 121 while (bits > 0); 122 val >>= -bits; 123 val &= ((1U << (operand->bits - 1)) << 1) - 1; 124 125 /* Check for special long displacement case. */ 126 if (operand->bits == 20 && operand->shift == 20) 127 val = (val & 0xff) << 12 | (val & 0xfff00) >> 8; 128 129 /* Sign extend value if the operand is signed or pc relative. Avoid 130 integer overflows. */ 131 if (operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL)) 132 { 133 unsigned int m = 1U << (operand->bits - 1); 134 135 if (val >= m) 136 ret.i = (int) (val - m) - 1 - (int) (m - 1U); 137 else 138 ret.i = (int) val; 139 } 140 else if (operand->flags & S390_OPERAND_LENGTH) 141 /* Length x in an instruction has real length x + 1. */ 142 ret.u = val + 1; 143 else 144 ret.u = val; 145 146 return ret; 147 } 148 149 /* Print the S390 instruction in BUFFER, assuming that it matches the 150 given OPCODE. */ 151 152 static void 153 s390_print_insn_with_opcode (bfd_vma memaddr, 154 struct disassemble_info *info, 155 const bfd_byte *buffer, 156 const struct s390_opcode *opcode) 157 { 158 const unsigned char *opindex; 159 char separator; 160 161 /* Mnemonic. */ 162 info->fprintf_func (info->stream, "%s", opcode->name); 163 164 /* Operands. */ 165 separator = '\t'; 166 for (opindex = opcode->operands; *opindex != 0; opindex++) 167 { 168 const struct s390_operand *operand = s390_operands + *opindex; 169 union operand_value val = s390_extract_operand (buffer, operand); 170 unsigned long flags = operand->flags; 171 172 if ((flags & S390_OPERAND_INDEX) && val.u == 0) 173 continue; 174 if ((flags & S390_OPERAND_BASE) && 175 val.u == 0 && separator == '(') 176 { 177 separator = ','; 178 continue; 179 } 180 181 info->fprintf_func (info->stream, "%c", separator); 182 183 if (flags & S390_OPERAND_GPR) 184 info->fprintf_func (info->stream, "%%r%u", val.u); 185 else if (flags & S390_OPERAND_FPR) 186 info->fprintf_func (info->stream, "%%f%u", val.u); 187 else if (flags & S390_OPERAND_AR) 188 info->fprintf_func (info->stream, "%%a%u", val.u); 189 else if (flags & S390_OPERAND_CR) 190 info->fprintf_func (info->stream, "%%c%u", val.u); 191 else if (flags & S390_OPERAND_PCREL) 192 info->print_address_func (memaddr + val.i + val.i, info); 193 else if (flags & S390_OPERAND_SIGNED) 194 info->fprintf_func (info->stream, "%i", val.i); 195 else 196 info->fprintf_func (info->stream, "%u", val.u); 197 198 if (flags & S390_OPERAND_DISP) 199 separator = '('; 200 else if (flags & S390_OPERAND_BASE) 201 { 202 info->fprintf_func (info->stream, ")"); 203 separator = ','; 204 } 205 else 206 separator = ','; 207 } 208 } 209 210 /* Check whether opcode A's mask is more specific than that of B. */ 211 212 static int 213 opcode_mask_more_specific (const struct s390_opcode *a, 214 const struct s390_opcode *b) 215 { 216 return (((int) a->mask[0] + a->mask[1] + a->mask[2] 217 + a->mask[3] + a->mask[4] + a->mask[5]) 218 > ((int) b->mask[0] + b->mask[1] + b->mask[2] 219 + b->mask[3] + b->mask[4] + b->mask[5])); 220 } 221 222 /* Print a S390 instruction. */ 223 224 int 225 print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info) 226 { 227 bfd_byte buffer[6]; 228 const struct s390_opcode *opcode = NULL; 229 unsigned int value; 230 int status, opsize, bufsize; 231 232 if (init_flag == 0) 233 init_disasm (info); 234 235 /* The output looks better if we put 6 bytes on a line. */ 236 info->bytes_per_line = 6; 237 238 /* Every S390 instruction is max 6 bytes long. */ 239 memset (buffer, 0, 6); 240 status = info->read_memory_func (memaddr, buffer, 6, info); 241 if (status != 0) 242 { 243 for (bufsize = 0; bufsize < 6; bufsize++) 244 if (info->read_memory_func (memaddr, buffer, bufsize + 1, info) != 0) 245 break; 246 if (bufsize <= 0) 247 { 248 info->memory_error_func (status, memaddr, info); 249 return -1; 250 } 251 opsize = s390_insn_length (buffer); 252 status = opsize > bufsize; 253 } 254 else 255 { 256 bufsize = 6; 257 opsize = s390_insn_length (buffer); 258 } 259 260 if (status == 0) 261 { 262 const struct s390_opcode *op; 263 264 /* Find the "best match" in the opcode table. */ 265 for (op = s390_opcodes + opc_index[buffer[0]]; 266 op != s390_opcodes + s390_num_opcodes 267 && op->opcode[0] == buffer[0]; 268 op++) 269 { 270 if ((op->modes & current_arch_mask) 271 && s390_insn_matches_opcode (buffer, op) 272 && (opcode == NULL 273 || opcode_mask_more_specific (op, opcode))) 274 opcode = op; 275 } 276 } 277 278 if (opcode != NULL) 279 { 280 /* The instruction is valid. Print it and return its size. */ 281 s390_print_insn_with_opcode (memaddr, info, buffer, opcode); 282 return opsize; 283 } 284 285 /* Fall back to hex print. */ 286 if (bufsize >= 4) 287 { 288 value = (unsigned int) buffer[0]; 289 value = (value << 8) + (unsigned int) buffer[1]; 290 value = (value << 8) + (unsigned int) buffer[2]; 291 value = (value << 8) + (unsigned int) buffer[3]; 292 info->fprintf_func (info->stream, ".long\t0x%08x", value); 293 return 4; 294 } 295 else if (bufsize >= 2) 296 { 297 value = (unsigned int) buffer[0]; 298 value = (value << 8) + (unsigned int) buffer[1]; 299 info->fprintf_func (info->stream, ".short\t0x%04x", value); 300 return 2; 301 } 302 else 303 { 304 value = (unsigned int) buffer[0]; 305 info->fprintf_func (info->stream, ".byte\t0x%02x", value); 306 return 1; 307 } 308 } 309 310 void 311 print_s390_disassembler_options (FILE *stream) 312 { 313 fprintf (stream, _("\n\ 314 The following S/390 specific disassembler options are supported for use\n\ 315 with the -M switch (multiple options should be separated by commas):\n")); 316 317 fprintf (stream, _(" esa Disassemble in ESA architecture mode\n")); 318 fprintf (stream, _(" zarch Disassemble in z/Architecture mode\n")); 319 } 320
