opcodes/s390-dis.c

   1 /* s390-dis.c -- Disassemble S390 instructions
   2    Copyright 2000, 2001, 2002, 2003, 2005 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., 51 Franklin Street - Fifth Floor, Boston, MA
  20    02110-1301, 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 (struct disassemble_info *info)
  36 {
  37   const struct s390_opcode *opcode;
  38   const struct s390_opcode *opcode_end;
  39
  40   memset (opc_index, 0, sizeof (opc_index));
  41   opcode_end = s390_opcodes + s390_num_opcodes;
  42   for (opcode = s390_opcodes; opcode < opcode_end; opcode++)
  43     {
  44       opc_index[(int) opcode->opcode[0]] = opcode - s390_opcodes;
  45       while ((opcode < opcode_end) &&
  46              (opcode[1].opcode[0] == opcode->opcode[0]))
  47         opcode++;
  48     }
  49   switch (info->mach)
  50     {
  51     case bfd_mach_s390_31:
  52       current_arch_mask = 1 << S390_OPCODE_ESA;
  53       break;
  54     case bfd_mach_s390_64:
  55       current_arch_mask = 1 << S390_OPCODE_ZARCH;
  56       break;
  57     default:
  58       abort ();
  59     }
  60   init_flag = 1;
  61 }
  62
  63 /* Extracts an operand value from an instruction.  */
  64
  65 static inline unsigned int
  66 s390_extract_operand (unsigned char *insn, const struct s390_operand *operand)
  67 {
  68   unsigned int val;
  69   int bits;
  70
  71   /* Extract fragments of the operand byte for byte.  */
  72   insn += operand->shift / 8;
  73   bits = (operand->shift & 7) + operand->bits;
  74   val = 0;
  75   do
  76     {
  77       val <<= 8;
  78       val |= (unsigned int) *insn++;
  79       bits -= 8;
  80     }
  81   while (bits > 0);
  82   val >>= -bits;
  83   val &= ((1U << (operand->bits - 1)) << 1) - 1;
  84
  85   /* Check for special long displacement case.  */
  86   if (operand->bits == 20 && operand->shift == 20)
  87     val = (val & 0xff) << 12 | (val & 0xfff00) >> 8;
  88
  89   /* Sign extend value if the operand is signed or pc relative.  */
  90   if ((operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL))
  91       && (val & (1U << (operand->bits - 1))))
  92     val |= (-1U << (operand->bits - 1)) << 1;
  93
  94   /* Double value if the operand is pc relative.  */
  95   if (operand->flags & S390_OPERAND_PCREL)
  96     val <<= 1;
  97
  98   /* Length x in an instructions has real length x + 1.  */
  99   if (operand->flags & S390_OPERAND_LENGTH)
 100     val++;
 101   return val;
 102 }
 103
 104 /* Print a S390 instruction.  */
 105
 106 int
 107 print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
 108 {
 109   bfd_byte buffer[6];
 110   const struct s390_opcode *opcode;
 111   const struct s390_opcode *opcode_end;
 112   unsigned int value;
 113   int status, opsize, bufsize;
 114   char separator;
 115
 116   if (init_flag == 0)
 117     init_disasm (info);
 118
 119   /* The output looks better if we put 6 bytes on a line.  */
 120   info->bytes_per_line = 6;
 121
 122   /* Every S390 instruction is max 6 bytes long.  */
 123   memset (buffer, 0, 6);
 124   status = (*info->read_memory_func) (memaddr, buffer, 6, info);
 125   if (status != 0)
 126     {
 127       for (bufsize = 0; bufsize < 6; bufsize++)
 128         if ((*info->read_memory_func) (memaddr, buffer, bufsize + 1, info) != 0)
 129           break;
 130       if (bufsize <= 0)
 131         {
 132           (*info->memory_error_func) (status, memaddr, info);
 133           return -1;
 134         }
 135       /* Opsize calculation looks strange but it works
 136          00xxxxxx -> 2 bytes, 01xxxxxx/10xxxxxx -> 4 bytes,
 137          11xxxxxx -> 6 bytes.  */
 138       opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
 139       status = opsize > bufsize;
 140     }
 141   else
 142     {
 143       bufsize = 6;
 144       opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
 145     }
 146
 147   if (status == 0)
 148     {
 149       /* Find the first match in the opcode table.  */
 150       opcode_end = s390_opcodes + s390_num_opcodes;
 151       for (opcode = s390_opcodes + opc_index[(int) buffer[0]];
 152            (opcode < opcode_end) && (buffer[0] == opcode->opcode[0]);
 153            opcode++)
 154         {
 155           const struct s390_operand *operand;
 156           const unsigned char *opindex;
 157
 158           /* Check architecture.  */
 159           if (!(opcode->modes & current_arch_mask))
 160             continue;
 161           /* Check signature of the opcode.  */
 162           if ((buffer[1] & opcode->mask[1]) != opcode->opcode[1]
 163               || (buffer[2] & opcode->mask[2]) != opcode->opcode[2]
 164               || (buffer[3] & opcode->mask[3]) != opcode->opcode[3]
 165               || (buffer[4] & opcode->mask[4]) != opcode->opcode[4]
 166               || (buffer[5] & opcode->mask[5]) != opcode->opcode[5])
 167             continue;
 168
 169           /* The instruction is valid.  */
 170           if (opcode->operands[0] != 0)
 171             (*info->fprintf_func) (info->stream, "%s\t", opcode->name);
 172           else
 173             (*info->fprintf_func) (info->stream, "%s", opcode->name);
 174
 175           /* Extract the operands.  */
 176           separator = 0;
 177           for (opindex = opcode->operands; *opindex != 0; opindex++)
 178             {
 179               unsigned int value;
 180
 181               operand = s390_operands + *opindex;
 182               value = s390_extract_operand (buffer, operand);
 183
 184               if ((operand->flags & S390_OPERAND_INDEX) && value == 0)
 185                 continue;
 186               if ((operand->flags & S390_OPERAND_BASE) &&
 187                   value == 0 && separator == '(')
 188                 {
 189                   separator = ',';
 190                   continue;
 191                 }
 192
 193               if (separator)
 194                 (*info->fprintf_func) (info->stream, "%c", separator);
 195
 196               if (operand->flags & S390_OPERAND_GPR)
 197                 (*info->fprintf_func) (info->stream, "%%r%i", value);
 198               else if (operand->flags & S390_OPERAND_FPR)
 199                 (*info->fprintf_func) (info->stream, "%%f%i", value);
 200               else if (operand->flags & S390_OPERAND_AR)
 201                 (*info->fprintf_func) (info->stream, "%%a%i", value);
 202               else if (operand->flags & S390_OPERAND_CR)
 203                 (*info->fprintf_func) (info->stream, "%%c%i", value);
 204               else if (operand->flags & S390_OPERAND_PCREL)
 205                 (*info->print_address_func) (memaddr + (int) value, info);
 206               else if (operand->flags & S390_OPERAND_SIGNED)
 207                 (*info->fprintf_func) (info->stream, "%i", (int) value);
 208               else
 209                 (*info->fprintf_func) (info->stream, "%u", value);
 210
 211               if (operand->flags & S390_OPERAND_DISP)
 212                 {
 213                   separator = '(';
 214                 }
 215               else if (operand->flags & S390_OPERAND_BASE)
 216                 {
 217                   (*info->fprintf_func) (info->stream, ")");
 218                   separator = ',';
 219                 }
 220               else
 221                 separator = ',';
 222             }
 223
 224           /* Found instruction, printed it, return its size.  */
 225           return opsize;
 226         }
 227       /* No matching instruction found, fall through to hex print.  */
 228     }
 229
 230   if (bufsize >= 4)
 231     {
 232       value = (unsigned int) buffer[0];
 233       value = (value << 8) + (unsigned int) buffer[1];
 234       value = (value << 8) + (unsigned int) buffer[2];
 235       value = (value << 8) + (unsigned int) buffer[3];
 236       (*info->fprintf_func) (info->stream, ".long\t0x%08x", value);
 237       return 4;
 238     }
 239   else if (bufsize >= 2)
 240     {
 241       value = (unsigned int) buffer[0];
 242       value = (value << 8) + (unsigned int) buffer[1];
 243       (*info->fprintf_func) (info->stream, ".short\t0x%04x", value);
 244       return 2;
 245     }
 246   else
 247     {
 248       value = (unsigned int) buffer[0];
 249       (*info->fprintf_func) (info->stream, ".byte\t0x%02x", value);
 250       return 1;
 251     }
 252 }