1 /* Print DEC PDP-11 instructions.
2 Copyright (C) 2001-2023 Free Software Foundation, Inc.
3
4 This file is part of the GNU opcodes library.
5
6 This library is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
9 any later version.
10
11 It is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
19 MA 02110-1301, USA. */
20
21 #include "sysdep.h"
22 #include "disassemble.h"
23 #include "opcode/pdp11.h"
24
25 #define AFTER_INSTRUCTION "\t"
26 #define OPERAND_SEPARATOR ", "
27
28 #define JUMP 0x1000 /* Flag that this operand is used in a jump. */
29
30 #define FPRINTF (*info->fprintf_func)
31 #define F info->stream
32
33 /* Sign-extend a 16-bit number in an int. */
34 #define sign_extend(x) ((((x) & 0xffff) ^ 0x8000) - 0x8000)
35
36 static int
37 read_word (bfd_vma memaddr, int *word, disassemble_info *info)
38 {
39 int status;
40 bfd_byte x[2];
41
42 status = (*info->read_memory_func) (memaddr, x, 2, info);
43 if (status != 0)
44 return -1;
45
46 *word = x[1] << 8 | x[0];
47 return 0;
48 }
49
50 static void
51 print_signed_octal (int n, disassemble_info *info)
52 {
53 if (n < 0)
54 FPRINTF (F, "-%o", -n);
55 else
56 FPRINTF (F, "%o", n);
57 }
58
59 static void
60 print_reg (int reg, disassemble_info *info)
61 {
62 /* Mask off the addressing mode, if any. */
63 reg &= 7;
64
65 switch (reg)
66 {
67 case 0: case 1: case 2: case 3: case 4: case 5:
68 FPRINTF (F, "r%d", reg); break;
69 case 6: FPRINTF (F, "sp"); break;
70 case 7: FPRINTF (F, "pc"); break;
71 default: ; /* error */
72 }
73 }
74
75 static void
76 print_freg (int freg, disassemble_info *info)
77 {
78 FPRINTF (F, "fr%d", freg);
79 }
80
81 static int
82 print_operand (bfd_vma *memaddr, int code, disassemble_info *info)
83 {
84 int mode = (code >> 3) & 7;
85 int reg = code & 7;
86 int disp;
87
88 switch (mode)
89 {
90 case 0:
91 print_reg (reg, info);
92 break;
93 case 1:
94 FPRINTF (F, "(");
95 print_reg (reg, info);
96 FPRINTF (F, ")");
97 break;
98 case 2:
99 if (reg == 7)
100 {
101 int data;
102
103 if (read_word (*memaddr, &data, info) < 0)
104 return -1;
105 FPRINTF (F, "$");
106 print_signed_octal (sign_extend (data), info);
107 *memaddr += 2;
108 }
109 else
110 {
111 FPRINTF (F, "(");
112 print_reg (reg, info);
113 FPRINTF (F, ")+");
114 }
115 break;
116 case 3:
117 if (reg == 7)
118 {
119 int address;
120
121 if (read_word (*memaddr, &address, info) < 0)
122 return -1;
123 FPRINTF (F, "*$%o", address);
124 *memaddr += 2;
125 }
126 else
127 {
128 FPRINTF (F, "*(");
129 print_reg (reg, info);
130 FPRINTF (F, ")+");
131 }
132 break;
133 case 4:
134 FPRINTF (F, "-(");
135 print_reg (reg, info);
136 FPRINTF (F, ")");
137 break;
138 case 5:
139 FPRINTF (F, "*-(");
140 print_reg (reg, info);
141 FPRINTF (F, ")");
142 break;
143 case 6:
144 case 7:
145 if (read_word (*memaddr, &disp, info) < 0)
146 return -1;
147 *memaddr += 2;
148 if (reg == 7)
149 {
150 bfd_vma address = *memaddr + sign_extend (disp);
151
152 if (mode == 7)
153 FPRINTF (F, "*");
154 if (!(code & JUMP))
155 FPRINTF (F, "$");
156 (*info->print_address_func) (address, info);
157 }
158 else
159 {
160 if (mode == 7)
161 FPRINTF (F, "*");
162 print_signed_octal (sign_extend (disp), info);
163 FPRINTF (F, "(");
164 print_reg (reg, info);
165 FPRINTF (F, ")");
166 }
167 break;
168 }
169
170 return 0;
171 }
172
173 static int
174 print_foperand (bfd_vma *memaddr, int code, disassemble_info *info)
175 {
176 int mode = (code >> 3) & 7;
177 int reg = code & 7;
178
179 if (mode == 0)
180 print_freg (reg, info);
181 else
182 return print_operand (memaddr, code, info);
183
184 return 0;
185 }
186
187 /* Print the PDP-11 instruction at address MEMADDR in debugged memory,
188 on INFO->STREAM. Returns length of the instruction, in bytes. */
189
190 int
191 print_insn_pdp11 (bfd_vma memaddr, disassemble_info *info)
192 {
193 bfd_vma start_memaddr = memaddr;
194 int opcode;
195 int src, dst;
196 int i;
197
198 info->bytes_per_line = 6;
199 info->bytes_per_chunk = 2;
200 info->display_endian = BFD_ENDIAN_LITTLE;
201
202 if (read_word (memaddr, &opcode, info) != 0)
203 return -1;
204 memaddr += 2;
205
206 src = (opcode >> 6) & 0x3f;
207 dst = opcode & 0x3f;
208
209 for (i = 0; i < pdp11_num_opcodes; i++)
210 {
211 #define OP pdp11_opcodes[i]
212 if ((opcode & OP.mask) == OP.opcode)
213 switch (OP.type)
214 {
215 case PDP11_OPCODE_NO_OPS:
216 FPRINTF (F, "%s", OP.name);
217 goto done;
218 case PDP11_OPCODE_REG:
219 FPRINTF (F, "%s", OP.name);
220 FPRINTF (F, AFTER_INSTRUCTION);
221 print_reg (dst, info);
222 goto done;
223 case PDP11_OPCODE_OP:
224 FPRINTF (F, "%s", OP.name);
225 FPRINTF (F, AFTER_INSTRUCTION);
226 if (strcmp (OP.name, "jmp") == 0)
227 dst |= JUMP;
228 if (print_operand (&memaddr, dst, info) < 0)
229 return -1;
230 goto done;
231 case PDP11_OPCODE_FOP:
232 FPRINTF (F, "%s", OP.name);
233 FPRINTF (F, AFTER_INSTRUCTION);
234 if (strcmp (OP.name, "jmp") == 0)
235 dst |= JUMP;
236 if (print_foperand (&memaddr, dst, info) < 0)
237 return -1;
238 goto done;
239 case PDP11_OPCODE_REG_OP:
240 FPRINTF (F, "%s", OP.name);
241 FPRINTF (F, AFTER_INSTRUCTION);
242 print_reg (src, info);
243 FPRINTF (F, OPERAND_SEPARATOR);
244 if (strcmp (OP.name, "jsr") == 0)
245 dst |= JUMP;
246 if (print_operand (&memaddr, dst, info) < 0)
247 return -1;
248 goto done;
249 case PDP11_OPCODE_REG_OP_REV:
250 FPRINTF (F, "%s", OP.name);
251 FPRINTF (F, AFTER_INSTRUCTION);
252 if (print_operand (&memaddr, dst, info) < 0)
253 return -1;
254 FPRINTF (F, OPERAND_SEPARATOR);
255 print_reg (src, info);
256 goto done;
257 case PDP11_OPCODE_AC_FOP:
258 {
259 int ac = (opcode & 0xe0) >> 6;
260 FPRINTF (F, "%s", OP.name);
261 FPRINTF (F, AFTER_INSTRUCTION);
262 print_freg (ac, info);
263 FPRINTF (F, OPERAND_SEPARATOR);
264 if (print_foperand (&memaddr, dst, info) < 0)
265 return -1;
266 goto done;
267 }
268 case PDP11_OPCODE_FOP_AC:
269 {
270 int ac = (opcode & 0xe0) >> 6;
271 FPRINTF (F, "%s", OP.name);
272 FPRINTF (F, AFTER_INSTRUCTION);
273 if (print_foperand (&memaddr, dst, info) < 0)
274 return -1;
275 FPRINTF (F, OPERAND_SEPARATOR);
276 print_freg (ac, info);
277 goto done;
278 }
279 case PDP11_OPCODE_AC_OP:
280 {
281 int ac = (opcode & 0xe0) >> 6;
282 FPRINTF (F, "%s", OP.name);
283 FPRINTF (F, AFTER_INSTRUCTION);
284 print_freg (ac, info);
285 FPRINTF (F, OPERAND_SEPARATOR);
286 if (print_operand (&memaddr, dst, info) < 0)
287 return -1;
288 goto done;
289 }
290 case PDP11_OPCODE_OP_AC:
291 {
292 int ac = (opcode & 0xe0) >> 6;
293 FPRINTF (F, "%s", OP.name);
294 FPRINTF (F, AFTER_INSTRUCTION);
295 if (print_operand (&memaddr, dst, info) < 0)
296 return -1;
297 FPRINTF (F, OPERAND_SEPARATOR);
298 print_freg (ac, info);
299 goto done;
300 }
301 case PDP11_OPCODE_OP_OP:
302 FPRINTF (F, "%s", OP.name);
303 FPRINTF (F, AFTER_INSTRUCTION);
304 if (print_operand (&memaddr, src, info) < 0)
305 return -1;
306 FPRINTF (F, OPERAND_SEPARATOR);
307 if (print_operand (&memaddr, dst, info) < 0)
308 return -1;
309 goto done;
310 case PDP11_OPCODE_DISPL:
311 {
312 int displ = (opcode & 0xff) << 8;
313 bfd_vma address = memaddr + (sign_extend (displ) >> 7);
314 FPRINTF (F, "%s", OP.name);
315 FPRINTF (F, AFTER_INSTRUCTION);
316 (*info->print_address_func) (address, info);
317 goto done;
318 }
319 case PDP11_OPCODE_REG_DISPL:
320 {
321 int displ = (opcode & 0x3f) << 10;
322 bfd_vma address = memaddr - (displ >> 9);
323
324 FPRINTF (F, "%s", OP.name);
325 FPRINTF (F, AFTER_INSTRUCTION);
326 print_reg (src, info);
327 FPRINTF (F, OPERAND_SEPARATOR);
328 (*info->print_address_func) (address, info);
329 goto done;
330 }
331 case PDP11_OPCODE_IMM8:
332 {
333 int code = opcode & 0xff;
334 FPRINTF (F, "%s", OP.name);
335 FPRINTF (F, AFTER_INSTRUCTION);
336 FPRINTF (F, "%o", code);
337 goto done;
338 }
339 case PDP11_OPCODE_IMM6:
340 {
341 int code = opcode & 0x3f;
342 FPRINTF (F, "%s", OP.name);
343 FPRINTF (F, AFTER_INSTRUCTION);
344 FPRINTF (F, "%o", code);
345 goto done;
346 }
347 case PDP11_OPCODE_IMM3:
348 {
349 int code = opcode & 7;
350 FPRINTF (F, "%s", OP.name);
351 FPRINTF (F, AFTER_INSTRUCTION);
352 FPRINTF (F, "%o", code);
353 goto done;
354 }
355 case PDP11_OPCODE_ILLEGAL:
356 {
357 FPRINTF (F, ".word");
358 FPRINTF (F, AFTER_INSTRUCTION);
359 FPRINTF (F, "%o", opcode);
360 goto done;
361 }
362 default:
363 /* TODO: is this a proper way of signalling an error? */
364 FPRINTF (F, "<internal error: unrecognized instruction type>");
365 return -1;
366 }
367 #undef OP
368 }
369 done:
370
371 return memaddr - start_memaddr;
372 }