opcodes/s390-dis.c

   1 /* s390-dis.c -- Disassemble S390 instructions
   2    Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
   3    Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
   4
   5    This file is part of GDB, GAS and the GNU binutils.
   6
   7    This program 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 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  20    02111-1307, USA.  */
  21
  22 #include <stdio.h>
  23 #include "ansidecl.h"
  24 #include "sysdep.h"
  25 #include "dis-asm.h"
  26 #include "opcode/s390.h"
  27
  28 static int init_flag = 0;
  29 static int opc_index[256];
  30 static int current_arch_mask = 0;
  31
  32 static void init_disasm PARAMS ((struct disassemble_info *));
  33 static unsigned int s390_extract_operand
  34   PARAMS ((unsigned char *, const struct s390_operand *));
  35
  36 /* Set up index table for first opcode byte.  */
  37
  38 static void
  39 init_disasm (info)
  40      struct disassemble_info *info;
  41 {
  42   const struct s390_opcode *opcode;
  43   const struct s390_opcode *opcode_end;
  44
  45   memset (opc_index, 0, sizeof (opc_index));
  46   opcode_end = s390_opcodes + s390_num_opcodes;
  47   for (opcode = s390_opcodes; opcode < opcode_end; opcode++)
  48     {
  49       opc_index[(int) opcode->opcode[0]] = opcode - s390_opcodes;
  50       while ((opcode < opcode_end) &&
  51              (opcode[1].opcode[0] == opcode->opcode[0]))
  52         opcode++;
  53     }
  54   switch (info->mach)
  55     {
  56     case bfd_mach_s390_31:
  57       current_arch_mask = 1 << S390_OPCODE_ESA;
  58       break;
  59     case bfd_mach_s390_64:
  60       current_arch_mask = 1 << S390_OPCODE_ZARCH;
  61       break;
  62     default:
  63       abort ();
  64     }
  65   init_flag = 1;
  66 }
  67
  68 /* Extracts an operand value from an instruction.  */
  69
  70 static inline unsigned int
  71 s390_extract_operand (insn, operand)
  72      unsigned char *insn;
  73      const struct s390_operand *operand;
  74 {
  75   unsigned int val;
  76   int bits;
  77
  78   /* Extract fragments of the operand byte for byte.  */
  79   insn += operand->shift / 8;
  80   bits = (operand->shift & 7) + operand->bits;
  81   val = 0;
  82   do
  83     {
  84       val <<= 8;
  85       val |= (unsigned int) *insn++;
  86       bits -= 8;
  87     }
  88   while (bits > 0);
  89   val >>= -bits;
  90   val &= ((1U << (operand->bits - 1)) << 1) - 1;
  91
  92   /* Sign extend value if the operand is signed or pc relative.  */
  93   if ((operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL))
  94       && (val & (1U << (operand->bits - 1))))
  95     val |= (-1U << (operand->bits - 1)) << 1;
  96
  97   /* Double value if the operand is pc relative.  */
  98   if (operand->flags & S390_OPERAND_PCREL)
  99     val <<= 1;
 100
 101   /* Length x in an instructions has real length x+1.  */
 102   if (operand->flags & S390_OPERAND_LENGTH)
 103     val++;
 104   return val;
 105 }
 106
 107 /* Print a S390 instruction.  */
 108
 109 int
 110 print_insn_s390 (memaddr, info)
 111      bfd_vma memaddr;
 112      struct disassemble_info *info;
 113 {
 114   bfd_byte buffer[6];
 115   const struct s390_opcode *opcode;
 116   const struct s390_opcode *opcode_end;
 117   unsigned int value;
 118   int status, opsize, bufsize;
 119   char separator;
 120
 121   if (init_flag == 0)
 122     init_disasm (info);
 123
 124   /* The output looks better if we put 6 bytes on a line.  */
 125   info->bytes_per_line = 6;
 126
 127   /* Every S390 instruction is max 6 bytes long.  */
 128   memset (buffer, 0, 6);
 129   status = (*info->read_memory_func) (memaddr, buffer, 6, info);
 130   if (status != 0)
 131     {
 132       for (bufsize = 0; bufsize < 6; bufsize++)
 133         if ((*info->read_memory_func) (memaddr, buffer, bufsize + 1, info) != 0)
 134           break;
 135       if (bufsize <= 0)
 136         {
 137           (*info->memory_error_func) (status, memaddr, info);
 138           return -1;
 139         }
 140       /* Opsize calculation looks strange but it works
 141          00xxxxxx -> 2 bytes, 01xxxxxx/10xxxxxx -> 4 bytes,
 142          11xxxxxx -> 6 bytes.  */
 143       opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
 144       status = opsize > bufsize;
 145     }
 146   else
 147     {
 148       bufsize = 6;
 149       opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
 150     }
 151
 152   if (status == 0)
 153     {
 154       /* Find the first match in the opcode table.  */
 155       opcode_end = s390_opcodes + s390_num_opcodes;
 156       for (opcode = s390_opcodes + opc_index[(int) buffer[0]];
 157            (opcode < opcode_end) && (buffer[0] == opcode->opcode[0]);
 158            opcode++)
 159         {
 160           const struct s390_operand *operand;
 161           const unsigned char *opindex;
 162
 163           /* Check architecture.  */
 164           if (!(opcode->modes & current_arch_mask))
 165             continue;
 166           /* Check signature of the opcode.  */
 167           if ((buffer[1] & opcode->mask[1]) != opcode->opcode[1]
 168               || (buffer[2] & opcode->mask[2]) != opcode->opcode[2]
 169               || (buffer[3] & opcode->mask[3]) != opcode->opcode[3]
 170               || (buffer[4] & opcode->mask[4]) != opcode->opcode[4]
 171               || (buffer[5] & opcode->mask[5]) != opcode->opcode[5])
 172             continue;
 173
 174           /* The instruction is valid.  */
 175           if (opcode->operands[0] != 0)
 176             (*info->fprintf_func) (info->stream, "%s\t", opcode->name);
 177           else
 178             (*info->fprintf_func) (info->stream, "%s", opcode->name);
 179
 180           /* Extract the operands.  */
 181           separator = 0;
 182           for (opindex = opcode->operands; *opindex != 0; opindex++)
 183             {
 184               unsigned int value;
 185
 186               operand = s390_operands + *opindex;
 187               value = s390_extract_operand (buffer, operand);
 188
 189               if ((operand->flags & S390_OPERAND_INDEX) && value == 0)
 190                 continue;
 191               if ((operand->flags & S390_OPERAND_BASE) &&
 192                   value == 0 && separator == '(')
 193                 {
 194                   separator = ',';
 195                   continue;
 196                 }
 197
 198               if (separator)
 199                 (*info->fprintf_func) (info->stream, "%c", separator);
 200
 201               if (operand->flags & S390_OPERAND_GPR)
 202                 (*info->fprintf_func) (info->stream, "%%r%i", value);
 203               else if (operand->flags & S390_OPERAND_FPR)
 204                 (*info->fprintf_func) (info->stream, "%%f%i", value);
 205               else if (operand->flags & S390_OPERAND_AR)
 206                 (*info->fprintf_func) (info->stream, "%%a%i", value);
 207               else if (operand->flags & S390_OPERAND_CR)
 208                 (*info->fprintf_func) (info->stream, "%%c%i", value);
 209               else if (operand->flags & S390_OPERAND_PCREL)
 210                 (*info->print_address_func) (memaddr + (int) value, info);
 211               else if (operand->flags & S390_OPERAND_SIGNED)
 212                 (*info->fprintf_func) (info->stream, "%i", (int) value);
 213               else
 214                 (*info->fprintf_func) (info->stream, "%i", value);
 215
 216               if (operand->flags & S390_OPERAND_DISP)
 217                 {
 218                   separator = '(';
 219                 }
 220               else if (operand->flags & S390_OPERAND_BASE)
 221                 {
 222                   (*info->fprintf_func) (info->stream, ")");
 223                   separator = ',';
 224                 }
 225               else
 226                 separator = ',';
 227             }
 228
 229           /* Found instruction, printed it, return its size.  */
 230           return opsize;
 231         }
 232       /* No matching instruction found, fall through to hex print.  */
 233     }
 234
 235   if (bufsize >= 4)
 236     {
 237       value = (unsigned int) buffer[0];
 238       value = (value << 8) + (unsigned int) buffer[1];
 239       value = (value << 8) + (unsigned int) buffer[2];
 240       value = (value << 8) + (unsigned int) buffer[3];
 241       (*info->fprintf_func) (info->stream, ".long\t0x%08x", value);
 242       return 4;
 243     }
 244   else if (bufsize >= 2)
 245     {
 246       value = (unsigned int) buffer[0];
 247       value = (value << 8) + (unsigned int) buffer[1];
 248       (*info->fprintf_func) (info->stream, ".short\t0x%04x", value);
 249       return 2;
 250     }
 251   else
 252     {
 253       value = (unsigned int) buffer[0];
 254       (*info->fprintf_func) (info->stream, ".byte\t0x%02x", value);
 255       return 1;
 256     }
 257 }