opcodes/i370-dis.c

   1 /* i370-dis.c -- Disassemble Instruction 370 (ESA/390) instructions
   2    Copyright 1994, 2000, 2003, 2005, 2007  Free Software Foundation, Inc.
   3    PowerPC version written by Ian Lance Taylor, Cygnus Support
   4    Rewritten for i370 ESA/390 support by Linas Vepstas <linas@linas.org>
   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 Free
  20    Software Foundation, 51 Franklin Street - Fifth Floor, Boston,
  21    MA 02110-1301, USA.  */
  22
  23 #include <stdio.h>
  24 #include "sysdep.h"
  25 #include "dis-asm.h"
  26 #include "opcode/i370.h"
  27
  28 /* This file provides several disassembler functions, all of which use
  29    the disassembler interface defined in dis-asm.h.  */
  30
  31 int
  32 print_insn_i370 (bfd_vma memaddr, struct disassemble_info *info)
  33 {
  34   bfd_byte buffer[8];
  35   int status;
  36   i370_insn_t insn;
  37   const struct i370_opcode *opcode;
  38   const struct i370_opcode *opcode_end;
  39
  40   status = (*info->read_memory_func) (memaddr, buffer, 6, info);
  41   if (status != 0)
  42     {
  43       (*info->memory_error_func) (status, memaddr, info);
  44       return -1;
  45     }
  46
  47   /* Cast the bytes into the insn (in a host-endian indep way).  */
  48   insn.i[0] = (buffer[0] << 24) & 0xff000000;
  49   insn.i[0] |= (buffer[1] << 16) & 0xff0000;
  50   insn.i[0] |= (buffer[2] << 8) & 0xff00;
  51   insn.i[0] |= buffer[3]  & 0xff;
  52   insn.i[1] = (buffer[4] << 24) & 0xff000000;
  53   insn.i[1] |= (buffer[5] << 16) & 0xff0000;
  54
  55   /* Find the first match in the opcode table.  We could speed this up
  56      a bit by doing a binary search on the major opcode.  */
  57   opcode_end = i370_opcodes + i370_num_opcodes;
  58   for (opcode = i370_opcodes; opcode < opcode_end; opcode++)
  59     {
  60       const unsigned char *opindex;
  61       const struct i370_operand *operand;
  62       i370_insn_t masked;
  63       int invalid;
  64
  65       /* Mask off operands, and look for a match ... */
  66       masked = insn;
  67       if (2 == opcode->len)
  68         {
  69           masked.i[0] >>= 16;
  70           masked.i[0] &= 0xffff;
  71         }
  72       masked.i[0] &= opcode->mask.i[0];
  73       if (masked.i[0] != opcode->opcode.i[0])
  74         continue;
  75
  76       if (6 == opcode->len)
  77         {
  78           masked.i[1] &= opcode->mask.i[1];
  79           if (masked.i[1] != opcode->opcode.i[1])
  80             continue;
  81         }
  82
  83       /* Found a match.  adjust a tad.  */
  84       if (2 == opcode->len)
  85         {
  86           insn.i[0] >>= 16;
  87           insn.i[0] &= 0xffff;
  88         }
  89
  90       /* Make two passes over the operands.  First see if any of them
  91          have extraction functions, and, if they do, make sure the
  92          instruction is valid.  */
  93       invalid = 0;
  94       for (opindex = opcode->operands; *opindex != 0; opindex++)
  95         {
  96           operand = i370_operands + *opindex;
  97           if (operand->extract)
  98             (*operand->extract) (insn, &invalid);
  99         }
 100       if (invalid)
 101         continue;
 102
 103       /* The instruction is valid.  */
 104       (*info->fprintf_func) (info->stream, "%s", opcode->name);
 105       if (opcode->operands[0] != 0)
 106         (*info->fprintf_func) (info->stream, "\t");
 107
 108       /* Now extract and print the operands.  */
 109       for (opindex = opcode->operands; *opindex != 0; opindex++)
 110         {
 111           long value;
 112
 113           operand = i370_operands + *opindex;
 114
 115           /* Extract the value from the instruction.  */
 116           if (operand->extract)
 117             value = (*operand->extract) (insn, (int *) NULL);
 118           else
 119             value = (insn.i[0] >> operand->shift) & ((1 << operand->bits) - 1);
 120
 121           /* Print the operand as directed by the flags.  */
 122           if ((operand->flags & I370_OPERAND_OPTIONAL) != 0)
 123             {
 124               if (value)
 125                 (*info->fprintf_func) (info->stream, "(r%ld)", value);
 126             }
 127           else if ((operand->flags & I370_OPERAND_SBASE) != 0)
 128             {
 129               (*info->fprintf_func) (info->stream, "(r%ld)", value);
 130             }
 131           else if ((operand->flags & I370_OPERAND_INDEX) != 0)
 132             {
 133               if (value)
 134                 (*info->fprintf_func) (info->stream, "(r%ld,", value);
 135               else
 136                 (*info->fprintf_func) (info->stream, "(,");
 137             }
 138           else if ((operand->flags & I370_OPERAND_LENGTH) != 0)
 139             {
 140               (*info->fprintf_func) (info->stream, "(%ld,", value);
 141             }
 142           else if ((operand->flags & I370_OPERAND_BASE) != 0)
 143             (*info->fprintf_func) (info->stream, "r%ld)", value);
 144           else if ((operand->flags & I370_OPERAND_GPR) != 0)
 145             (*info->fprintf_func) (info->stream, "r%ld,", value);
 146           else if ((operand->flags & I370_OPERAND_FPR) != 0)
 147             (*info->fprintf_func) (info->stream, "f%ld,", value);
 148           else if ((operand->flags & I370_OPERAND_RELATIVE) != 0)
 149             (*info->fprintf_func) (info->stream, "%ld", value);
 150           else
 151             (*info->fprintf_func) (info->stream, " %ld, ", value);
 152         }
 153
 154       return opcode->len;
 155     }
 156
 157   /* We could not find a match.  */
 158   (*info->fprintf_func) (info->stream, ".short 0x%02x%02x", buffer[0], buffer[1]);
 159
 160   return 2;
 161 }