opcodes/s390-dis.c

   1 /* s390-dis.c -- Disassemble S390 instructions
   2    Copyright 2000, 2001, 2002, 2003, 2005, 2007 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 <stdio.h>
  23 #include "ansidecl.h"
  24 #include "sysdep.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   const struct s390_opcode *opcode;
  39   const struct s390_opcode *opcode_end;
  40   const char *p;
  41
  42   memset (opc_index, 0, sizeof (opc_index));
  43   opcode_end = s390_opcodes + s390_num_opcodes;
  44   for (opcode = s390_opcodes; opcode < opcode_end; opcode++)
  45     {
  46       opc_index[(int) opcode->opcode[0]] = opcode - s390_opcodes;
  47       while ((opcode < opcode_end) &&
  48              (opcode[1].opcode[0] == opcode->opcode[0]))
  49         opcode++;
  50     }
  51
  52   for (p = info->disassembler_options; p != NULL; )
  53     {
  54       if (CONST_STRNEQ (p, "esa"))
  55         current_arch_mask = 1 << S390_OPCODE_ESA;
  56       else if (CONST_STRNEQ (p, "zarch"))
  57         current_arch_mask = 1 << S390_OPCODE_ZARCH;
  58       else
  59         fprintf (stderr, "Unknown S/390 disassembler option: %s\n", p);
  60
  61       p = strchr (p, ',');
  62       if (p != NULL)
  63         p++;
  64     }
  65
  66   if (!current_arch_mask)
  67     switch (info->mach)
  68       {
  69       case bfd_mach_s390_31:
  70         current_arch_mask = 1 << S390_OPCODE_ESA;
  71         break;
  72       case bfd_mach_s390_64:
  73         current_arch_mask = 1 << S390_OPCODE_ZARCH;
  74         break;
  75       default:
  76         abort ();
  77       }
  78
  79   init_flag = 1;
  80 }
  81
  82 /* Extracts an operand value from an instruction.  */
  83
  84 static inline unsigned int
  85 s390_extract_operand (unsigned char *insn, const struct s390_operand *operand)
  86 {
  87   unsigned int val;
  88   int bits;
  89
  90   /* Extract fragments of the operand byte for byte.  */
  91   insn += operand->shift / 8;
  92   bits = (operand->shift & 7) + operand->bits;
  93   val = 0;
  94   do
  95     {
  96       val <<= 8;
  97       val |= (unsigned int) *insn++;
  98       bits -= 8;
  99     }
 100   while (bits > 0);
 101   val >>= -bits;
 102   val &= ((1U << (operand->bits - 1)) << 1) - 1;
 103
 104   /* Check for special long displacement case.  */
 105   if (operand->bits == 20 && operand->shift == 20)
 106     val = (val & 0xff) << 12 | (val & 0xfff00) >> 8;
 107
 108   /* Sign extend value if the operand is signed or pc relative.  */
 109   if ((operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL))
 110       && (val & (1U << (operand->bits - 1))))
 111     val |= (-1U << (operand->bits - 1)) << 1;
 112
 113   /* Double value if the operand is pc relative.  */
 114   if (operand->flags & S390_OPERAND_PCREL)
 115     val <<= 1;
 116
 117   /* Length x in an instructions has real length x + 1.  */
 118   if (operand->flags & S390_OPERAND_LENGTH)
 119     val++;
 120   return val;
 121 }
 122
 123 /* Print a S390 instruction.  */
 124
 125 int
 126 print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
 127 {
 128   bfd_byte buffer[6];
 129   const struct s390_opcode *opcode;
 130   const struct s390_opcode *opcode_end;
 131   unsigned int value;
 132   int status, opsize, bufsize;
 133   char separator;
 134
 135   if (init_flag == 0)
 136     init_disasm (info);
 137
 138   /* The output looks better if we put 6 bytes on a line.  */
 139   info->bytes_per_line = 6;
 140
 141   /* Every S390 instruction is max 6 bytes long.  */
 142   memset (buffer, 0, 6);
 143   status = (*info->read_memory_func) (memaddr, buffer, 6, info);
 144   if (status != 0)
 145     {
 146       for (bufsize = 0; bufsize < 6; bufsize++)
 147         if ((*info->read_memory_func) (memaddr, buffer, bufsize + 1, info) != 0)
 148           break;
 149       if (bufsize <= 0)
 150         {
 151           (*info->memory_error_func) (status, memaddr, info);
 152           return -1;
 153         }
 154       /* Opsize calculation looks strange but it works
 155          00xxxxxx -> 2 bytes, 01xxxxxx/10xxxxxx -> 4 bytes,
 156          11xxxxxx -> 6 bytes.  */
 157       opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
 158       status = opsize > bufsize;
 159     }
 160   else
 161     {
 162       bufsize = 6;
 163       opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
 164     }
 165
 166   if (status == 0)
 167     {
 168       /* Find the first match in the opcode table.  */
 169       opcode_end = s390_opcodes + s390_num_opcodes;
 170       for (opcode = s390_opcodes + opc_index[(int) buffer[0]];
 171            (opcode < opcode_end) && (buffer[0] == opcode->opcode[0]);
 172            opcode++)
 173         {
 174           const struct s390_operand *operand;
 175           const unsigned char *opindex;
 176
 177           /* Check architecture.  */
 178           if (!(opcode->modes & current_arch_mask))
 179             continue;
 180           /* Check signature of the opcode.  */
 181           if ((buffer[1] & opcode->mask[1]) != opcode->opcode[1]
 182               || (buffer[2] & opcode->mask[2]) != opcode->opcode[2]
 183               || (buffer[3] & opcode->mask[3]) != opcode->opcode[3]
 184               || (buffer[4] & opcode->mask[4]) != opcode->opcode[4]
 185               || (buffer[5] & opcode->mask[5]) != opcode->opcode[5])
 186             continue;
 187
 188           /* The instruction is valid.  */
 189           if (opcode->operands[0] != 0)
 190             (*info->fprintf_func) (info->stream, "%s\t", opcode->name);
 191           else
 192             (*info->fprintf_func) (info->stream, "%s", opcode->name);
 193
 194           /* Extract the operands.  */
 195           separator = 0;
 196           for (opindex = opcode->operands; *opindex != 0; opindex++)
 197             {
 198               unsigned int value;
 199
 200               operand = s390_operands + *opindex;
 201               value = s390_extract_operand (buffer, operand);
 202
 203               if ((operand->flags & S390_OPERAND_INDEX) && value == 0)
 204                 continue;
 205               if ((operand->flags & S390_OPERAND_BASE) &&
 206                   value == 0 && separator == '(')
 207                 {
 208                   separator = ',';
 209                   continue;
 210                 }
 211
 212               if (separator)
 213                 (*info->fprintf_func) (info->stream, "%c", separator);
 214
 215               if (operand->flags & S390_OPERAND_GPR)
 216                 (*info->fprintf_func) (info->stream, "%%r%i", value);
 217               else if (operand->flags & S390_OPERAND_FPR)
 218                 (*info->fprintf_func) (info->stream, "%%f%i", value);
 219               else if (operand->flags & S390_OPERAND_AR)
 220                 (*info->fprintf_func) (info->stream, "%%a%i", value);
 221               else if (operand->flags & S390_OPERAND_CR)
 222                 (*info->fprintf_func) (info->stream, "%%c%i", value);
 223               else if (operand->flags & S390_OPERAND_PCREL)
 224                 (*info->print_address_func) (memaddr + (int) value, info);
 225               else if (operand->flags & S390_OPERAND_SIGNED)
 226                 (*info->fprintf_func) (info->stream, "%i", (int) value);
 227               else
 228                 (*info->fprintf_func) (info->stream, "%u", value);
 229
 230               if (operand->flags & S390_OPERAND_DISP)
 231                 {
 232                   separator = '(';
 233                 }
 234               else if (operand->flags & S390_OPERAND_BASE)
 235                 {
 236                   (*info->fprintf_func) (info->stream, ")");
 237                   separator = ',';
 238                 }
 239               else
 240                 separator = ',';
 241             }
 242
 243           /* Found instruction, printed it, return its size.  */
 244           return opsize;
 245         }
 246       /* No matching instruction found, fall through to hex print.  */
 247     }
 248
 249   if (bufsize >= 4)
 250     {
 251       value = (unsigned int) buffer[0];
 252       value = (value << 8) + (unsigned int) buffer[1];
 253       value = (value << 8) + (unsigned int) buffer[2];
 254       value = (value << 8) + (unsigned int) buffer[3];
 255       (*info->fprintf_func) (info->stream, ".long\t0x%08x", value);
 256       return 4;
 257     }
 258   else if (bufsize >= 2)
 259     {
 260       value = (unsigned int) buffer[0];
 261       value = (value << 8) + (unsigned int) buffer[1];
 262       (*info->fprintf_func) (info->stream, ".short\t0x%04x", value);
 263       return 2;
 264     }
 265   else
 266     {
 267       value = (unsigned int) buffer[0];
 268       (*info->fprintf_func) (info->stream, ".byte\t0x%02x", value);
 269       return 1;
 270     }
 271 }
 272
 273 void
 274 print_s390_disassembler_options (FILE *stream)
 275 {
 276   fprintf (stream, _("\n\
 277 The following S/390 specific disassembler options are supported for use\n\
 278 with the -M switch (multiple options should be separated by commas):\n"));
 279
 280   fprintf (stream, _("  esa         Disassemble in ESA architecture mode\n"));
 281   fprintf (stream, _("  zarch       Disassemble in z/Architecture mode\n"));
 282 }