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[binutils.git] / opcodes / s390-dis.c
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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).
5 This file is part of GDB, GAS and the GNU binutils.
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.
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.
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. */
22 #include <stdio.h>
23 #include "ansidecl.h"
24 #include "sysdep.h"
25 #include "dis-asm.h"
26 #include "opcode/s390.h"
28 static int init_flag = 0;
29 static int opc_index[256];
30 static int current_arch_mask = 0;
32 /* Set up index table for first opcode byte. */
34 static void
35 init_disasm (struct disassemble_info *info)
37 const struct s390_opcode *opcode;
38 const struct s390_opcode *opcode_end;
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++)
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++;
49 switch (info->mach)
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 ();
60 init_flag = 1;
63 /* Extracts an operand value from an instruction. */
65 static inline unsigned int
66 s390_extract_operand (unsigned char *insn, const struct s390_operand *operand)
68 unsigned int val;
69 int bits;
71 /* Extract fragments of the operand byte for byte. */
72 insn += operand->shift / 8;
73 bits = (operand->shift & 7) + operand->bits;
74 val = 0;
77 val <<= 8;
78 val |= (unsigned int) *insn++;
79 bits -= 8;
81 while (bits > 0);
82 val >>= -bits;
83 val &= ((1U << (operand->bits - 1)) << 1) - 1;
85 /* Check for special long displacement case. */
86 if (operand->bits == 20 && operand->shift == 20)
87 val = (val & 0xff) << 12 | (val & 0xfff00) >> 8;
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;
94 /* Double value if the operand is pc relative. */
95 if (operand->flags & S390_OPERAND_PCREL)
96 val <<= 1;
98 /* Length x in an instructions has real length x + 1. */
99 if (operand->flags & S390_OPERAND_LENGTH)
100 val++;
101 return val;
104 /* Print a S390 instruction. */
107 print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
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;
116 if (init_flag == 0)
117 init_disasm (info);
119 /* The output looks better if we put 6 bytes on a line. */
120 info->bytes_per_line = 6;
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)
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)
132 (*info->memory_error_func) (status, memaddr, info);
133 return -1;
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;
141 else
143 bufsize = 6;
144 opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
147 if (status == 0)
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++)
155 const struct s390_operand *operand;
156 const unsigned char *opindex;
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;
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);
175 /* Extract the operands. */
176 separator = 0;
177 for (opindex = opcode->operands; *opindex != 0; opindex++)
179 unsigned int value;
181 operand = s390_operands + *opindex;
182 value = s390_extract_operand (buffer, operand);
184 if ((operand->flags & S390_OPERAND_INDEX) && value == 0)
185 continue;
186 if ((operand->flags & S390_OPERAND_BASE) &&
187 value == 0 && separator == '(')
189 separator = ',';
190 continue;
193 if (separator)
194 (*info->fprintf_func) (info->stream, "%c", separator);
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);
211 if (operand->flags & S390_OPERAND_DISP)
213 separator = '(';
215 else if (operand->flags & S390_OPERAND_BASE)
217 (*info->fprintf_func) (info->stream, ")");
218 separator = ',';
220 else
221 separator = ',';
224 /* Found instruction, printed it, return its size. */
225 return opsize;
227 /* No matching instruction found, fall through to hex print. */
230 if (bufsize >= 4)
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;
239 else if (bufsize >= 2)
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;
246 else
248 value = (unsigned int) buffer[0];
249 (*info->fprintf_func) (info->stream, ".byte\t0x%02x", value);
250 return 1;