1/* i370-dis.c -- Disassemble Instruction 370 (ESA/390) instructions
2   Copyright (C) 1994-2017 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 "sysdep.h"
24#include <stdio.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