1 /* s390-dis.c -- Disassemble S390 instructions
2 Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
3 Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
4
5 This file is part of GDB, GAS and the GNU binutils.
6
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.
11
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.
16
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., 59 Temple Place - Suite 330, Boston, MA
20 02111-1307, USA. */
21
22 #include <stdio.h>
23 #include "ansidecl.h"
24 #include "sysdep.h"
25 #include "dis-asm.h"
26 #include "opcode/s390.h"
27
28 static int init_flag = 0;
29 static int opc_index[256];
30 static int current_arch_mask = 0;
31
32 static void init_disasm PARAMS ((struct disassemble_info *));
33 static unsigned int s390_extract_operand
34 PARAMS ((unsigned char *, const struct s390_operand *));
35
36 /* Set up index table for first opcode byte. */
37
38 static void
init_disasm(info)39 init_disasm (info)
40 struct disassemble_info *info;
41 {
42 const struct s390_opcode *opcode;
43 const struct s390_opcode *opcode_end;
44
45 memset (opc_index, 0, sizeof (opc_index));
46 opcode_end = s390_opcodes + s390_num_opcodes;
47 for (opcode = s390_opcodes; opcode < opcode_end; opcode++)
48 {
49 opc_index[(int) opcode->opcode[0]] = opcode - s390_opcodes;
50 while ((opcode < opcode_end) &&
51 (opcode[1].opcode[0] == opcode->opcode[0]))
52 opcode++;
53 }
54 switch (info->mach)
55 {
56 case bfd_mach_s390_31:
57 current_arch_mask = 1 << S390_OPCODE_ESA;
58 break;
59 case bfd_mach_s390_64:
60 current_arch_mask = 1 << S390_OPCODE_ZARCH;
61 break;
62 default:
63 abort ();
64 }
65 init_flag = 1;
66 }
67
68 /* Extracts an operand value from an instruction. */
69
70 static inline unsigned int
s390_extract_operand(insn,operand)71 s390_extract_operand (insn, operand)
72 unsigned char *insn;
73 const struct s390_operand *operand;
74 {
75 unsigned int val;
76 int bits;
77
78 /* Extract fragments of the operand byte for byte. */
79 insn += operand->shift / 8;
80 bits = (operand->shift & 7) + operand->bits;
81 val = 0;
82 do
83 {
84 val <<= 8;
85 val |= (unsigned int) *insn++;
86 bits -= 8;
87 }
88 while (bits > 0);
89 val >>= -bits;
90 val &= ((1U << (operand->bits - 1)) << 1) - 1;
91
92 /* Check for special long displacement case. */
93 if (operand->bits == 20 && operand->shift == 20)
94 val = (val & 0xff) << 12 | (val & 0xfff00) >> 8;
95
96 /* Sign extend value if the operand is signed or pc relative. */
97 if ((operand->flags & (S390_OPERAND_SIGNED | S390_OPERAND_PCREL))
98 && (val & (1U << (operand->bits - 1))))
99 val |= (-1U << (operand->bits - 1)) << 1;
100
101 /* Double value if the operand is pc relative. */
102 if (operand->flags & S390_OPERAND_PCREL)
103 val <<= 1;
104
105 /* Length x in an instructions has real length x+1. */
106 if (operand->flags & S390_OPERAND_LENGTH)
107 val++;
108 return val;
109 }
110
111 /* Print a S390 instruction. */
112
113 int
print_insn_s390(memaddr,info)114 print_insn_s390 (memaddr, info)
115 bfd_vma memaddr;
116 struct disassemble_info *info;
117 {
118 bfd_byte buffer[6];
119 const struct s390_opcode *opcode;
120 const struct s390_opcode *opcode_end;
121 unsigned int value;
122 int status, opsize, bufsize;
123 char separator;
124
125 if (init_flag == 0)
126 init_disasm (info);
127
128 /* The output looks better if we put 6 bytes on a line. */
129 info->bytes_per_line = 6;
130
131 /* Every S390 instruction is max 6 bytes long. */
132 memset (buffer, 0, 6);
133 status = (*info->read_memory_func) (memaddr, buffer, 6, info);
134 if (status != 0)
135 {
136 for (bufsize = 0; bufsize < 6; bufsize++)
137 if ((*info->read_memory_func) (memaddr, buffer, bufsize + 1, info) != 0)
138 break;
139 if (bufsize <= 0)
140 {
141 (*info->memory_error_func) (status, memaddr, info);
142 return -1;
143 }
144 /* Opsize calculation looks strange but it works
145 00xxxxxx -> 2 bytes, 01xxxxxx/10xxxxxx -> 4 bytes,
146 11xxxxxx -> 6 bytes. */
147 opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
148 status = opsize > bufsize;
149 }
150 else
151 {
152 bufsize = 6;
153 opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
154 }
155
156 if (status == 0)
157 {
158 /* Find the first match in the opcode table. */
159 opcode_end = s390_opcodes + s390_num_opcodes;
160 for (opcode = s390_opcodes + opc_index[(int) buffer[0]];
161 (opcode < opcode_end) && (buffer[0] == opcode->opcode[0]);
162 opcode++)
163 {
164 const struct s390_operand *operand;
165 const unsigned char *opindex;
166
167 /* Check architecture. */
168 if (!(opcode->modes & current_arch_mask))
169 continue;
170 /* Check signature of the opcode. */
171 if ((buffer[1] & opcode->mask[1]) != opcode->opcode[1]
172 || (buffer[2] & opcode->mask[2]) != opcode->opcode[2]
173 || (buffer[3] & opcode->mask[3]) != opcode->opcode[3]
174 || (buffer[4] & opcode->mask[4]) != opcode->opcode[4]
175 || (buffer[5] & opcode->mask[5]) != opcode->opcode[5])
176 continue;
177
178 /* The instruction is valid. */
179 if (opcode->operands[0] != 0)
180 (*info->fprintf_func) (info->stream, "%s\t", opcode->name);
181 else
182 (*info->fprintf_func) (info->stream, "%s", opcode->name);
183
184 /* Extract the operands. */
185 separator = 0;
186 for (opindex = opcode->operands; *opindex != 0; opindex++)
187 {
188 unsigned int value;
189
190 operand = s390_operands + *opindex;
191 value = s390_extract_operand (buffer, operand);
192
193 if ((operand->flags & S390_OPERAND_INDEX) && value == 0)
194 continue;
195 if ((operand->flags & S390_OPERAND_BASE) &&
196 value == 0 && separator == '(')
197 {
198 separator = ',';
199 continue;
200 }
201
202 if (separator)
203 (*info->fprintf_func) (info->stream, "%c", separator);
204
205 if (operand->flags & S390_OPERAND_GPR)
206 (*info->fprintf_func) (info->stream, "%%r%i", value);
207 else if (operand->flags & S390_OPERAND_FPR)
208 (*info->fprintf_func) (info->stream, "%%f%i", value);
209 else if (operand->flags & S390_OPERAND_AR)
210 (*info->fprintf_func) (info->stream, "%%a%i", value);
211 else if (operand->flags & S390_OPERAND_CR)
212 (*info->fprintf_func) (info->stream, "%%c%i", value);
213 else if (operand->flags & S390_OPERAND_PCREL)
214 (*info->print_address_func) (memaddr + (int) value, info);
215 else if (operand->flags & S390_OPERAND_SIGNED)
216 (*info->fprintf_func) (info->stream, "%i", (int) value);
217 else
218 (*info->fprintf_func) (info->stream, "%i", value);
219
220 if (operand->flags & S390_OPERAND_DISP)
221 {
222 separator = '(';
223 }
224 else if (operand->flags & S390_OPERAND_BASE)
225 {
226 (*info->fprintf_func) (info->stream, ")");
227 separator = ',';
228 }
229 else
230 separator = ',';
231 }
232
233 /* Found instruction, printed it, return its size. */
234 return opsize;
235 }
236 /* No matching instruction found, fall through to hex print. */
237 }
238
239 if (bufsize >= 4)
240 {
241 value = (unsigned int) buffer[0];
242 value = (value << 8) + (unsigned int) buffer[1];
243 value = (value << 8) + (unsigned int) buffer[2];
244 value = (value << 8) + (unsigned int) buffer[3];
245 (*info->fprintf_func) (info->stream, ".long\t0x%08x", value);
246 return 4;
247 }
248 else if (bufsize >= 2)
249 {
250 value = (unsigned int) buffer[0];
251 value = (value << 8) + (unsigned int) buffer[1];
252 (*info->fprintf_func) (info->stream, ".short\t0x%04x", value);
253 return 2;
254 }
255 else
256 {
257 value = (unsigned int) buffer[0];
258 (*info->fprintf_func) (info->stream, ".byte\t0x%02x", value);
259 return 1;
260 }
261 }
262