opcodes/s390-dis.c

   1 /* s390-dis.c -- Disassemble S390 instructions
   2    Copyright 2000, 2001, 2002, 2003, 2005, 2007, 2008
   3    Free Software Foundation, Inc.
   4    Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
   5
   6    This file is part of the GNU opcodes library.
   7
   8    This library is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3, or (at your option)
  11    any later version.
  12
  13    It is distributed in the hope that it will be useful, but WITHOUT
  14    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  16    License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this file; see the file COPYING.  If not, write to the
  20    Free Software Foundation, 51 Franklin Street - Fifth Floor, Boston,
  21    MA 02110-1301, USA.  */
  22
  23 #include <stdio.h>
  24 #include "ansidecl.h"
  25 #include "sysdep.h"
  26 #include "dis-asm.h"
  27 #include "opintl.h"
  28 #include "opcode/s390.h"
  29
  30 static int init_flag = 0;
  31 static int opc_index[256];
  32 static int current_arch_mask = 0;
  33
  34 /* Set up index table for first opcode byte.  */
  35
  36 static void
  37 init_disasm (struct disassemble_info *info)
  38 {
  39   const struct s390_opcode *opcode;
  40   const struct s390_opcode *opcode_end;
  41   const char *p;
  42
  43   memset (opc_index, 0, sizeof (opc_index));
  44   opcode_end = s390_opcodes + s390_num_opcodes;
  45   for (opcode = s390_opcodes; opcode < opcode_end; opcode++)
  46     {
  47       opc_index[(int) opcode->opcode[0]] = opcode - s390_opcodes;
  48       while ((opcode < opcode_end) &&
  49              (opcode[1].opcode[0] == opcode->opcode[0]))
  50         opcode++;
  51     }
  52
  53   for (p = info->disassembler_options; p != NULL; )
  54     {
  55       if (CONST_STRNEQ (p, "esa"))
  56         current_arch_mask = 1 << S390_OPCODE_ESA;
  57       else if (CONST_STRNEQ (p, "zarch"))
  58         current_arch_mask = 1 << S390_OPCODE_ZARCH;
  59       else
  60         fprintf (stderr, "Unknown S/390 disassembler option: %s\n", p);
  61
  62       p = strchr (p, ',');
  63       if (p != NULL)
  64         p++;
  65     }
  66
  67   if (!current_arch_mask)
  68     switch (info->mach)
  69       {
  70       case bfd_mach_s390_31:
  71         current_arch_mask = 1 << S390_OPCODE_ESA;
  72         break;
  73       case bfd_mach_s390_64:
  74         current_arch_mask = 1 << S390_OPCODE_ZARCH;
  75         break;
  76       default:
  77         abort ();
  78       }
  79
  80   init_flag = 1;
  81 }
  82
  83 /* Extracts an operand value from an instruction.  */
  84
  85 static inline unsigned int
  86 s390_extract_operand (unsigned char *insn, const struct s390_operand *operand)
  87 {
  88   unsigned int val;
  89   int bits;
  90
  91   /* Extract fragments of the operand byte for byte.  */
  92   insn += operand->shift / 8;
  93   bits = (operand->shift & 7) + operand->bits;
  94   val = 0;
  95   do
  96     {
  97       val <<= 8;
  98       val |= (unsigned int) *insn++;
  99       bits -= 8;
 100     }
 101   while (bits > 0);
 102   val >>= -bits;
 103   val &= ((1U << (operand->bits - 1)) << 1) - 1;
 104
 105   /* Check for special long displacement case.  */
 106   if (operand->bits == 20 && operand->shift == 20)
 107     val = (val & 0xff) << 12 | (val & 0xfff00) >> 8;
 108
 109   /* Sign extend value if the operand is signed or pc relative.  */
 110   if ((operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL))
 111       && (val & (1U << (operand->bits - 1))))
 112     val |= (-1U << (operand->bits - 1)) << 1;
 113
 114   /* Double value if the operand is pc relative.  */
 115   if (operand->flags & S390_OPERAND_PCREL)
 116     val <<= 1;
 117
 118   /* Length x in an instructions has real length x + 1.  */
 119   if (operand->flags & S390_OPERAND_LENGTH)
 120     val++;
 121   return val;
 122 }
 123
 124 /* Print a S390 instruction.  */
 125
 126 int
 127 print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
 128 {
 129   bfd_byte buffer[6];
 130   const struct s390_opcode *opcode;
 131   const struct s390_opcode *opcode_end;
 132   unsigned int value;
 133   int status, opsize, bufsize;
 134   char separator;
 135
 136   if (init_flag == 0)
 137     init_disasm (info);
 138
 139   /* The output looks better if we put 6 bytes on a line.  */
 140   info->bytes_per_line = 6;
 141
 142   /* Every S390 instruction is max 6 bytes long.  */
 143   memset (buffer, 0, 6);
 144   status = (*info->read_memory_func) (memaddr, buffer, 6, info);
 145   if (status != 0)
 146     {
 147       for (bufsize = 0; bufsize < 6; bufsize++)
 148         if ((*info->read_memory_func) (memaddr, buffer, bufsize + 1, info) != 0)
 149           break;
 150       if (bufsize <= 0)
 151         {
 152           (*info->memory_error_func) (status, memaddr, info);
 153           return -1;
 154         }
 155       /* Opsize calculation looks strange but it works
 156          00xxxxxx -> 2 bytes, 01xxxxxx/10xxxxxx -> 4 bytes,
 157          11xxxxxx -> 6 bytes.  */
 158       opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
 159       status = opsize > bufsize;
 160     }
 161   else
 162     {
 163       bufsize = 6;
 164       opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
 165     }
 166
 167   if (status == 0)
 168     {
 169       /* Find the first match in the opcode table.  */
 170       opcode_end = s390_opcodes + s390_num_opcodes;
 171       for (opcode = s390_opcodes + opc_index[(int) buffer[0]];
 172            (opcode < opcode_end) && (buffer[0] == opcode->opcode[0]);
 173            opcode++)
 174         {
 175           const struct s390_operand *operand;
 176           const unsigned char *opindex;
 177
 178           /* Check architecture.  */
 179           if (!(opcode->modes & current_arch_mask))
 180             continue;
 181           /* Check signature of the opcode.  */
 182           if ((buffer[1] & opcode->mask[1]) != opcode->opcode[1]
 183               || (buffer[2] & opcode->mask[2]) != opcode->opcode[2]
 184               || (buffer[3] & opcode->mask[3]) != opcode->opcode[3]
 185               || (buffer[4] & opcode->mask[4]) != opcode->opcode[4]
 186               || (buffer[5] & opcode->mask[5]) != opcode->opcode[5])
 187             continue;
 188
 189           /* The instruction is valid.  */
 190           if (opcode->operands[0] != 0)
 191             (*info->fprintf_func) (info->stream, "%s\t", opcode->name);
 192           else
 193             (*info->fprintf_func) (info->stream, "%s", opcode->name);
 194
 195           /* Extract the operands.  */
 196           separator = 0;
 197           for (opindex = opcode->operands; *opindex != 0; opindex++)
 198             {
 199               unsigned int value;
 200
 201               operand = s390_operands + *opindex;
 202               value = s390_extract_operand (buffer, operand);
 203
 204               if ((operand->flags & S390_OPERAND_INDEX) && value == 0)
 205                 continue;
 206               if ((operand->flags & S390_OPERAND_BASE) &&
 207                   value == 0 && separator == '(')
 208                 {
 209                   separator = ',';
 210                   continue;
 211                 }
 212
 213               if (separator)
 214                 (*info->fprintf_func) (info->stream, "%c", separator);
 215
 216               if (operand->flags & S390_OPERAND_GPR)
 217                 (*info->fprintf_func) (info->stream, "%%r%i", value);
 218               else if (operand->flags & S390_OPERAND_FPR)
 219                 (*info->fprintf_func) (info->stream, "%%f%i", value);
 220               else if (operand->flags & S390_OPERAND_AR)
 221                 (*info->fprintf_func) (info->stream, "%%a%i", value);
 222               else if (operand->flags & S390_OPERAND_CR)
 223                 (*info->fprintf_func) (info->stream, "%%c%i", value);
 224               else if (operand->flags & S390_OPERAND_PCREL)
 225                 (*info->print_address_func) (memaddr + (int) value, info);
 226               else if (operand->flags & S390_OPERAND_SIGNED)
 227                 (*info->fprintf_func) (info->stream, "%i", (int) value);
 228               else
 229                 (*info->fprintf_func) (info->stream, "%u", value);
 230
 231               if (operand->flags & S390_OPERAND_DISP)
 232                 {
 233                   separator = '(';
 234                 }
 235               else if (operand->flags & S390_OPERAND_BASE)
 236                 {
 237                   (*info->fprintf_func) (info->stream, ")");
 238                   separator = ',';
 239                 }
 240               else
 241                 separator = ',';
 242             }
 243
 244           /* Found instruction, printed it, return its size.  */
 245           return opsize;
 246         }
 247       /* No matching instruction found, fall through to hex print.  */
 248     }
 249
 250   if (bufsize >= 4)
 251     {
 252       value = (unsigned int) buffer[0];
 253       value = (value << 8) + (unsigned int) buffer[1];
 254       value = (value << 8) + (unsigned int) buffer[2];
 255       value = (value << 8) + (unsigned int) buffer[3];
 256       (*info->fprintf_func) (info->stream, ".long\t0x%08x", value);
 257       return 4;
 258     }
 259   else if (bufsize >= 2)
 260     {
 261       value = (unsigned int) buffer[0];
 262       value = (value << 8) + (unsigned int) buffer[1];
 263       (*info->fprintf_func) (info->stream, ".short\t0x%04x", value);
 264       return 2;
 265     }
 266   else
 267     {
 268       value = (unsigned int) buffer[0];
 269       (*info->fprintf_func) (info->stream, ".byte\t0x%02x", value);
 270       return 1;
 271     }
 272 }
 273
 274 void
 275 print_s390_disassembler_options (FILE *stream)
 276 {
 277   fprintf (stream, _("\n\
 278 The following S/390 specific disassembler options are supported for use\n\
 279 with the -M switch (multiple options should be separated by commas):\n"));
 280
 281   fprintf (stream, _("  esa         Disassemble in ESA architecture mode\n"));
 282   fprintf (stream, _("  zarch       Disassemble in z/Architecture mode\n"));
 283 }