opcodes/s390-dis.c

   1 /* s390-dis.c -- Disassemble S390 instructions
   2    Copyright 2000, 2001 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 /* Set up index table for first opcode byte.  */
  33
  34 static void
  35 init_disasm (info)
  36      struct disassemble_info *info ATTRIBUTE_UNUSED;
  37 {
  38   const struct s390_opcode *opcode;
  39   const struct s390_opcode *opcode_end;
  40
  41   memset (opc_index, 0, sizeof (opc_index));
  42   opcode_end = s390_opcodes + s390_num_opcodes;
  43   for (opcode = s390_opcodes; opcode < opcode_end; opcode++)
  44     {
  45       opc_index[(int) opcode->opcode[0]] = opcode - s390_opcodes;
  46       while ((opcode < opcode_end) &&
  47              (opcode[1].opcode[0] == opcode->opcode[0]))
  48         opcode++;
  49     }
  50   switch (info->mach)
  51     {
  52     case bfd_mach_s390_esa:
  53       current_arch_mask = 1 << S390_OPCODE_ESA;
  54       break;
  55     case bfd_mach_s390_esame:
  56       current_arch_mask = 1 << S390_OPCODE_ESAME;
  57       break;
  58     default:
  59       abort ();
  60     }
  61   init_flag = 1;
  62 }
  63
  64 /* Extracts an operand value from an instruction.  */
  65
  66 static inline unsigned int
  67 s390_extract_operand (insn, operand)
  68      unsigned char *insn;
  69      const struct s390_operand *operand;
  70 {
  71   unsigned int val;
  72   int bits;
  73
  74   /* Extract fragments of the operand byte for byte.  */
  75   insn += operand->shift / 8;
  76   bits = (operand->shift & 7) + operand->bits;
  77   val = 0;
  78   do
  79     {
  80       val <<= 8;
  81       val |= (unsigned int) *insn++;
  82       bits -= 8;
  83     }
  84   while (bits > 0);
  85   val >>= -bits;
  86   val &= ((1U << (operand->bits - 1)) << 1) - 1;
  87
  88   /* Sign extend value if the operand is signed or pc relative.  */
  89   if ((operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL))
  90       && (val & (1U << (operand->bits - 1))))
  91     val |= (-1U << (operand->bits - 1)) << 1;
  92
  93   /* Double value if the operand is pc relative.  */
  94   if (operand->flags & S390_OPERAND_PCREL)
  95     val <<= 1;
  96
  97   /* Length x in an instructions has real length x+1.  */
  98   if (operand->flags & S390_OPERAND_LENGTH)
  99     val++;
 100   return val;
 101 }
 102
 103 /* Print a S390 instruction.  */
 104
 105 int
 106 print_insn_s390 (memaddr, info)
 107      bfd_vma memaddr;
 108      struct disassemble_info *info;
 109 {
 110   bfd_byte buffer[6];
 111   const struct s390_opcode *opcode;
 112   const struct s390_opcode *opcode_end;
 113   unsigned int value;
 114   int status, opsize, bufsize;
 115   char separator;
 116
 117   if (init_flag == 0)
 118     init_disasm (info);
 119
 120   /* The output looks better if we put 6 bytes on a line.  */
 121   info->bytes_per_line = 6;
 122
 123   /* Every S390 instruction is max 6 bytes long.  */
 124   memset (buffer, 0, 6);
 125   status = (*info->read_memory_func) (memaddr, buffer, 6, info);
 126   if (status != 0)
 127     {
 128       for (bufsize = 0; bufsize < 6; bufsize++)
 129         if ((*info->read_memory_func) (memaddr, buffer, bufsize + 1, info) != 0)
 130           break;
 131       if (bufsize <= 0)
 132         {
 133           (*info->memory_error_func) (status, memaddr, info);
 134           return -1;
 135         }
 136       /* Opsize calculation looks strange but it works
 137          00xxxxxx -> 2 bytes, 01xxxxxx/10xxxxxx -> 4 bytes,
 138          11xxxxxx -> 6 bytes.  */
 139       opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
 140       status = opsize > bufsize;
 141     }
 142   else
 143     {
 144       bufsize = 6;
 145       opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
 146     }
 147
 148   if (status == 0)
 149     {
 150       /* Find the first match in the opcode table.  */
 151       opcode_end = s390_opcodes + s390_num_opcodes;
 152       for (opcode = s390_opcodes + opc_index[(int) buffer[0]];
 153            (opcode < opcode_end) && (buffer[0] == opcode->opcode[0]);
 154            opcode++)
 155         {
 156           const struct s390_operand *operand;
 157           const unsigned char *opindex;
 158
 159           /* Check architecture.  */
 160           if (!(opcode->architecture & current_arch_mask))
 161             continue;
 162           /* Check signature of the opcode.  */
 163           if ((buffer[1] & opcode->mask[1]) != opcode->opcode[1]
 164               || (buffer[2] & opcode->mask[2]) != opcode->opcode[2]
 165               || (buffer[3] & opcode->mask[3]) != opcode->opcode[3]
 166               || (buffer[4] & opcode->mask[4]) != opcode->opcode[4]
 167               || (buffer[5] & opcode->mask[5]) != opcode->opcode[5])
 168             continue;
 169
 170           /* The instruction is valid.  */
 171           if (opcode->operands[0] != 0)
 172             (*info->fprintf_func) (info->stream, "%s\t", opcode->name);
 173           else
 174             (*info->fprintf_func) (info->stream, "%s", opcode->name);
 175
 176           /* Extract the operands.  */
 177           separator = 0;
 178           for (opindex = opcode->operands; *opindex != 0; opindex++)
 179             {
 180               unsigned int value;
 181
 182               operand = s390_operands + *opindex;
 183               value = s390_extract_operand (buffer, operand);
 184
 185               if ((operand->flags & S390_OPERAND_INDEX) && value == 0)
 186                 continue;
 187               if ((operand->flags & S390_OPERAND_BASE) &&
 188                   value == 0 && separator == '(')
 189                 {
 190                   separator = ',';
 191                   continue;
 192                 }
 193
 194               if (separator)
 195                 (*info->fprintf_func) (info->stream, "%c", separator);
 196
 197               if (operand->flags & S390_OPERAND_GPR)
 198                 (*info->fprintf_func) (info->stream, "%%r%i", value);
 199               else if (operand->flags & S390_OPERAND_FPR)
 200                 (*info->fprintf_func) (info->stream, "%%f%i", value);
 201               else if (operand->flags & S390_OPERAND_AR)
 202                 (*info->fprintf_func) (info->stream, "%%a%i", value);
 203               else if (operand->flags & S390_OPERAND_CR)
 204                 (*info->fprintf_func) (info->stream, "%%c%i", value);
 205               else if (operand->flags & S390_OPERAND_PCREL)
 206                 (*info->print_address_func) (memaddr + (int) value, info);
 207               else if (operand->flags & S390_OPERAND_SIGNED)
 208                 (*info->fprintf_func) (info->stream, "%i", (int) value);
 209               else
 210                 (*info->fprintf_func) (info->stream, "%i", value);
 211
 212               if (operand->flags & S390_OPERAND_DISP)
 213                 {
 214                   separator = '(';
 215                 }
 216               else if (operand->flags & S390_OPERAND_BASE)
 217                 {
 218                   (*info->fprintf_func) (info->stream, ")");
 219                   separator = ',';
 220                 }
 221               else
 222                 separator = ',';
 223             }
 224
 225           /* Found instruction, printed it, return its size.  */
 226           return opsize;
 227         }
 228       /* No matching instruction found, fall through to hex print.  */
 229     }
 230
 231   if (bufsize >= 4)
 232     {
 233       value = (unsigned int) buffer[0];
 234       value = (value << 8) + (unsigned int) buffer[1];
 235       value = (value << 8) + (unsigned int) buffer[2];
 236       value = (value << 8) + (unsigned int) buffer[3];
 237       (*info->fprintf_func) (info->stream, ".long\t0x%08x", value);
 238       return 4;
 239     }
 240   else if (bufsize >= 2)
 241     {
 242       value = (unsigned int) buffer[0];
 243       value = (value << 8) + (unsigned int) buffer[1];
 244       (*info->fprintf_func) (info->stream, ".short\t0x%04x", value);
 245       return 2;
 246     }
 247   else
 248     {
 249       value = (unsigned int) buffer[0];
 250       (*info->fprintf_func) (info->stream, ".byte\t0x%02x", value);
 251       return 1;
 252     }
 253 }