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).
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., 51 Franklin Street - Fifth Floor, Boston, MA
20 02110-1301, 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 /* Set up index table for first opcode byte. */
33
34 static void
init_disasm(struct disassemble_info * info)35 init_disasm (struct disassemble_info *info)
36 {
37 const struct s390_opcode *opcode;
38 const struct s390_opcode *opcode_end;
39
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++)
43 {
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++;
48 }
49 switch (info->mach)
50 {
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 ();
59 }
60 init_flag = 1;
61 }
62
63 /* Extracts an operand value from an instruction. */
64
65 static inline unsigned int
s390_extract_operand(unsigned char * insn,const struct s390_operand * operand)66 s390_extract_operand (unsigned char *insn, const struct s390_operand *operand)
67 {
68 unsigned int val;
69 int bits;
70
71 /* Extract fragments of the operand byte for byte. */
72 insn += operand->shift / 8;
73 bits = (operand->shift & 7) + operand->bits;
74 val = 0;
75 do
76 {
77 val <<= 8;
78 val |= (unsigned int) *insn++;
79 bits -= 8;
80 }
81 while (bits > 0);
82 val >>= -bits;
83 val &= ((1U << (operand->bits - 1)) << 1) - 1;
84
85 /* Check for special long displacement case. */
86 if (operand->bits == 20 && operand->shift == 20)
87 val = (val & 0xff) << 12 | (val & 0xfff00) >> 8;
88
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;
93
94 /* Double value if the operand is pc relative. */
95 if (operand->flags & S390_OPERAND_PCREL)
96 val <<= 1;
97
98 /* Length x in an instructions has real length x + 1. */
99 if (operand->flags & S390_OPERAND_LENGTH)
100 val++;
101 return val;
102 }
103
104 /* Print a S390 instruction. */
105
106 int
print_insn_s390(bfd_vma memaddr,struct disassemble_info * info)107 print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
108 {
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;
115
116 if (init_flag == 0)
117 init_disasm (info);
118
119 /* The output looks better if we put 6 bytes on a line. */
120 info->bytes_per_line = 6;
121
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)
126 {
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)
131 {
132 (*info->memory_error_func) (status, memaddr, info);
133 return -1;
134 }
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;
140 }
141 else
142 {
143 bufsize = 6;
144 opsize = ((((buffer[0] >> 6) + 1) >> 1) + 1) << 1;
145 }
146
147 if (status == 0)
148 {
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++)
154 {
155 const struct s390_operand *operand;
156 const unsigned char *opindex;
157
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;
168
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);
174
175 /* Extract the operands. */
176 separator = 0;
177 for (opindex = opcode->operands; *opindex != 0; opindex++)
178 {
179 unsigned int value;
180
181 operand = s390_operands + *opindex;
182 value = s390_extract_operand (buffer, operand);
183
184 if ((operand->flags & S390_OPERAND_INDEX) && value == 0)
185 continue;
186 if ((operand->flags & S390_OPERAND_BASE) &&
187 value == 0 && separator == '(')
188 {
189 separator = ',';
190 continue;
191 }
192
193 if (separator)
194 (*info->fprintf_func) (info->stream, "%c", separator);
195
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);
210
211 if (operand->flags & S390_OPERAND_DISP)
212 {
213 separator = '(';
214 }
215 else if (operand->flags & S390_OPERAND_BASE)
216 {
217 (*info->fprintf_func) (info->stream, ")");
218 separator = ',';
219 }
220 else
221 separator = ',';
222 }
223
224 /* Found instruction, printed it, return its size. */
225 return opsize;
226 }
227 /* No matching instruction found, fall through to hex print. */
228 }
229
230 if (bufsize >= 4)
231 {
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;
238 }
239 else if (bufsize >= 2)
240 {
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;
245 }
246 else
247 {
248 value = (unsigned int) buffer[0];
249 (*info->fprintf_func) (info->stream, ".byte\t0x%02x", value);
250 return 1;
251 }
252 }
253