gnu/dist/gdb6/opcodes/i370-dis.c

   1 /* i370-dis.c -- Disassemble Instruction 370 (ESA/390) instructions
   2    Copyright 1994, 2000, 2003, 2005 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 GDB, GAS, and the GNU binutils.
   7
   8    GDB, GAS, and the GNU binutils are free software; you can redistribute
   9    them and/or modify them under the terms of the GNU General Public
  10    License as published by the Free Software Foundation; either version
  11    2, or (at your option) any later version.
  12
  13    GDB, GAS, and the GNU binutils are distributed in the hope that they
  14    will be useful, but WITHOUT ANY WARRANTY; without even the implied
  15    warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  16    the GNU General Public 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 }