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
31int
32print_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}
162