* serial.c (serial_close): If scb is NULL, don't try to close
[deliverable/binutils-gdb.git] / gdb / h8300-tdep.c
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1/* Target-machine dependent code for Hitachi H8/300, for GDB.
2 Copyright (C) 1988, 1990, 1991 Free Software Foundation, Inc.
3
4This file is part of GDB.
5
6This program is free software; you can redistribute it and/or modify
7it under the terms of the GNU General Public License as published by
8the Free Software Foundation; either version 2 of the License, or
9(at your option) any later version.
10
11This program is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14GNU General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with this program; if not, write to the Free Software
18Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
19
ec25d19b 20/*
1f46923f 21 Contributed by Steve Chamberlain
ec25d19b 22 sac@cygnus.com
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23 */
24
400943fb 25#include "defs.h"
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26#include "frame.h"
27#include "obstack.h"
28#include "symtab.h"
df14b38b 29#include <dis-asm.h>
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30#undef NUM_REGS
31#define NUM_REGS 11
32
1f46923f 33#define UNSIGNED_SHORT(X) ((X) & 0xffff)
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34
35/* an easy to debug H8 stack frame looks like:
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360x6df6 push r6
370x0d76 mov.w r7,r6
380x6dfn push reg
390x7905 nnnn mov.w #n,r5 or 0x1b87 subs #2,sp
400x1957 sub.w r5,sp
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41
42 */
1f46923f 43
400943fb 44#define IS_PUSH(x) ((x & 0xff00)==0x6d00)
ec25d19b 45#define IS_PUSH_FP(x) (x == 0x6df6)
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46#define IS_MOVE_FP(x) (x == 0x0d76)
47#define IS_MOV_SP_FP(x) (x == 0x0d76)
48#define IS_SUB2_SP(x) (x==0x1b87)
49#define IS_MOVK_R5(x) (x==0x7905)
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50#define IS_SUB_R5SP(x) (x==0x1957)
51CORE_ADDR examine_prologue ();
1f46923f 52
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53void frame_find_saved_regs ();
54CORE_ADDR
55h8300_skip_prologue (start_pc)
56 CORE_ADDR start_pc;
0a8f9d31 57
0a8f9d31 58{
ec25d19b 59 short int w;
1f46923f 60
df14b38b 61 w = read_memory_unsigned_integer (start_pc, 2);
400943fb 62 /* Skip past all push insns */
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63 while (IS_PUSH_FP (w))
64 {
65 start_pc += 2;
df14b38b 66 w = read_memory_unsigned_integer (start_pc, 2);
ec25d19b 67 }
0a8f9d31 68
1f46923f 69 /* Skip past a move to FP */
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70 if (IS_MOVE_FP (w))
71 {
72 start_pc += 2;
df14b38b 73 w = read_memory_unsigned_integer (start_pc, 2);
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74 }
75
ec25d19b 76 /* Skip the stack adjust */
0a8f9d31 77
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78 if (IS_MOVK_R5 (w))
79 {
80 start_pc += 2;
df14b38b 81 w = read_memory_unsigned_integer (start_pc, 2);
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82 }
83 if (IS_SUB_R5SP (w))
84 {
85 start_pc += 2;
df14b38b 86 w = read_memory_unsigned_integer (start_pc, 2);
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87 }
88 while (IS_SUB2_SP (w))
89 {
90 start_pc += 2;
df14b38b 91 w = read_memory_unsigned_integer (start_pc, 2);
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92 }
93
94 return start_pc;
95
96}
1f46923f 97
400943fb 98int
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99print_insn (memaddr, stream)
100 CORE_ADDR memaddr;
101 FILE *stream;
0a8f9d31 102{
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103 disassemble_info info;
104 GDB_INIT_DISASSEMBLE_INFO(info, stream);
105 return print_insn_h8300 (memaddr, &info);
0a8f9d31 106}
ec25d19b 107
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108/* Given a GDB frame, determine the address of the calling function's frame.
109 This will be used to create a new GDB frame struct, and then
110 INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame.
111
112 For us, the frame address is its stack pointer value, so we look up
113 the function prologue to determine the caller's sp value, and return it. */
114
115FRAME_ADDR
116FRAME_CHAIN (thisframe)
117 FRAME thisframe;
118{
119
120 frame_find_saved_regs (thisframe, (struct frame_saved_regs *) 0);
ec25d19b 121 return thisframe->fsr->regs[SP_REGNUM];
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122}
123
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124/* Put here the code to store, into a struct frame_saved_regs,
125 the addresses of the saved registers of frame described by FRAME_INFO.
126 This includes special registers such as pc and fp saved in special
127 ways in the stack frame. sp is even more special:
128 the address we return for it IS the sp for the next frame.
129
130 We cache the result of doing this in the frame_cache_obstack, since
131 it is fairly expensive. */
132
133void
134frame_find_saved_regs (fi, fsr)
135 struct frame_info *fi;
136 struct frame_saved_regs *fsr;
137{
138 register CORE_ADDR next_addr;
139 register CORE_ADDR *saved_regs;
140 register int regnum;
141 register struct frame_saved_regs *cache_fsr;
142 extern struct obstack frame_cache_obstack;
143 CORE_ADDR ip;
144 struct symtab_and_line sal;
145 CORE_ADDR limit;
146
147 if (!fi->fsr)
148 {
149 cache_fsr = (struct frame_saved_regs *)
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150 obstack_alloc (&frame_cache_obstack,
151 sizeof (struct frame_saved_regs));
1f46923f 152 bzero (cache_fsr, sizeof (struct frame_saved_regs));
ec25d19b 153
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154 fi->fsr = cache_fsr;
155
156 /* Find the start and end of the function prologue. If the PC
157 is in the function prologue, we only consider the part that
158 has executed already. */
ec25d19b 159
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160 ip = get_pc_function_start (fi->pc);
161 sal = find_pc_line (ip, 0);
ec25d19b 162 limit = (sal.end && sal.end < fi->pc) ? sal.end : fi->pc;
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163
164 /* This will fill in fields in *fi as well as in cache_fsr. */
165 examine_prologue (ip, limit, fi->frame, cache_fsr, fi);
166 }
167
168 if (fsr)
169 *fsr = *fi->fsr;
170}
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171
172/* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
173 is not the address of a valid instruction, the address of the next
174 instruction beyond ADDR otherwise. *PWORD1 receives the first word
175 of the instruction.*/
176
1f46923f 177CORE_ADDR
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178NEXT_PROLOGUE_INSN (addr, lim, pword1)
179 CORE_ADDR addr;
180 CORE_ADDR lim;
181 short *pword1;
1f46923f 182{
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183 if (addr < lim + 8)
184 {
185 read_memory (addr, pword1, sizeof (*pword1));
186 SWAP_TARGET_AND_HOST (pword1, sizeof (short));
1f46923f 187
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188 return addr + 2;
189 }
1f46923f 190 return 0;
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191}
192
193/* Examine the prologue of a function. `ip' points to the first instruction.
ec25d19b 194 `limit' is the limit of the prologue (e.g. the addr of the first
1f46923f 195 linenumber, or perhaps the program counter if we're stepping through).
ec25d19b 196 `frame_sp' is the stack pointer value in use in this frame.
1f46923f 197 `fsr' is a pointer to a frame_saved_regs structure into which we put
ec25d19b 198 info about the registers saved by this frame.
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199 `fi' is a struct frame_info pointer; we fill in various fields in it
200 to reflect the offsets of the arg pointer and the locals pointer. */
201
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202static CORE_ADDR
203examine_prologue (ip, limit, after_prolog_fp, fsr, fi)
204 register CORE_ADDR ip;
205 register CORE_ADDR limit;
206 FRAME_ADDR after_prolog_fp;
207 struct frame_saved_regs *fsr;
208 struct frame_info *fi;
209{
210 register CORE_ADDR next_ip;
211 int r;
212 int i;
213 int have_fp = 0;
ec25d19b 214
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215 register int src;
216 register struct pic_prologue_code *pcode;
217 INSN_WORD insn_word;
218 int size, offset;
ddf30c37 219 unsigned int reg_save_depth = 2; /* Number of things pushed onto
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220 stack, starts at 2, 'cause the
221 PC is already there */
222
223 unsigned int auto_depth = 0; /* Number of bytes of autos */
1f46923f 224
ddf30c37 225 char in_frame[11]; /* One for each reg */
1f46923f 226
ddf30c37 227 memset (in_frame, 1, 11);
256b4f37 228 for (r = 0; r < 8; r++)
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229 {
230 fsr->regs[r] = 0;
231 }
232 if (after_prolog_fp == 0)
233 {
234 after_prolog_fp = read_register (SP_REGNUM);
235 }
236 if (ip == 0 || ip & ~0xffff)
237 return 0;
1f46923f 238
ec25d19b 239 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
1f46923f 240
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241 /* Skip over any fp push instructions */
242 fsr->regs[6] = after_prolog_fp;
243 while (next_ip && IS_PUSH_FP (insn_word))
244 {
245 ip = next_ip;
1f46923f 246
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247 in_frame[insn_word & 0x7] = reg_save_depth;
248 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
249 reg_save_depth += 2;
250 }
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251
252 /* Is this a move into the fp */
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253 if (next_ip && IS_MOV_SP_FP (insn_word))
254 {
255 ip = next_ip;
256 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
257 have_fp = 1;
258 }
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259
260 /* Skip over any stack adjustment, happens either with a number of
261 sub#2,sp or a mov #x,r5 sub r5,sp */
262
ec25d19b 263 if (next_ip && IS_SUB2_SP (insn_word))
1f46923f 264 {
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265 while (next_ip && IS_SUB2_SP (insn_word))
266 {
267 auto_depth += 2;
268 ip = next_ip;
269 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
270 }
1f46923f 271 }
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272 else
273 {
274 if (next_ip && IS_MOVK_R5 (insn_word))
275 {
276 ip = next_ip;
277 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
278 auto_depth += insn_word;
279
280 next_ip = NEXT_PROLOGUE_INSN (next_ip, limit, &insn_word);
281 auto_depth += insn_word;
282
283 }
284 }
285 /* Work out which regs are stored where */
286 while (next_ip && IS_PUSH (insn_word))
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287 {
288 ip = next_ip;
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289 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
290 fsr->regs[r] = after_prolog_fp + auto_depth;
291 auto_depth += 2;
1f46923f 292 }
1f46923f 293
1f46923f 294 /* The args are always reffed based from the stack pointer */
ec25d19b 295 fi->args_pointer = after_prolog_fp;
1f46923f 296 /* Locals are always reffed based from the fp */
ec25d19b 297 fi->locals_pointer = after_prolog_fp;
1f46923f 298 /* The PC is at a known place */
df14b38b 299 fi->from_pc = read_memory_unsigned_integer (after_prolog_fp + 2, BINWORD);
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300
301 /* Rememeber any others too */
1f46923f 302 in_frame[PC_REGNUM] = 0;
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303
304 if (have_fp)
305 /* We keep the old FP in the SP spot */
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306 fsr->regs[SP_REGNUM] = (read_memory_unsigned_integer
307 (fsr->regs[6]), BINWORD);
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308 else
309 fsr->regs[SP_REGNUM] = after_prolog_fp + auto_depth;
310
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311 return (ip);
312}
313
314void
315init_extra_frame_info (fromleaf, fi)
316 int fromleaf;
317 struct frame_info *fi;
318{
319 fi->fsr = 0; /* Not yet allocated */
320 fi->args_pointer = 0; /* Unknown */
321 fi->locals_pointer = 0; /* Unknown */
322 fi->from_pc = 0;
ec25d19b 323
1f46923f 324}
ec25d19b 325
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326/* Return the saved PC from this frame.
327
328 If the frame has a memory copy of SRP_REGNUM, use that. If not,
329 just use the register SRP_REGNUM itself. */
330
331CORE_ADDR
332frame_saved_pc (frame)
ec25d19b 333 FRAME frame;
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334
335{
336 return frame->from_pc;
337}
338
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339CORE_ADDR
340frame_locals_address (fi)
341 struct frame_info *fi;
342{
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343 if (!fi->locals_pointer)
344 {
345 struct frame_saved_regs ignore;
346
347 get_frame_saved_regs (fi, &ignore);
1f46923f 348
ec25d19b 349 }
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350 return fi->locals_pointer;
351}
352
353/* Return the address of the argument block for the frame
354 described by FI. Returns 0 if the address is unknown. */
355
356CORE_ADDR
357frame_args_address (fi)
358 struct frame_info *fi;
359{
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360 if (!fi->args_pointer)
361 {
362 struct frame_saved_regs ignore;
363
364 get_frame_saved_regs (fi, &ignore);
365
366 }
1f46923f 367
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368 return fi->args_pointer;
369}
370
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371void
372h8300_pop_frame ()
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373{
374 unsigned regnum;
375 struct frame_saved_regs fsr;
376 struct frame_info *fi;
377
ec25d19b 378 FRAME frame = get_current_frame ();
1f46923f 379
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380 fi = get_frame_info (frame);
381 get_frame_saved_regs (fi, &fsr);
382
256b4f37 383 for (regnum = 0; regnum < 8; regnum++)
1f46923f 384 {
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385 if (fsr.regs[regnum])
386 {
df14b38b 387 write_register (regnum, read_memory_integer(fsr.regs[regnum]), BINWORD);
ec25d19b
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388 }
389
390 flush_cached_frames ();
391 set_current_frame (create_new_frame (read_register (FP_REGNUM),
392 read_pc ()));
393
1f46923f 394 }
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395
396}
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397
398void
399print_register_hook (regno)
400{
401 if (regno == 8)
402 {
403 /* CCR register */
404
405 int C, Z, N, V;
406 unsigned char b[2];
407 unsigned char l;
408
409 read_relative_register_raw_bytes (regno, b);
410 l = b[1];
411 printf ("\t");
412 printf ("I-%d - ", (l & 0x80) != 0);
413 printf ("H-%d - ", (l & 0x20) != 0);
414 N = (l & 0x8) != 0;
415 Z = (l & 0x4) != 0;
416 V = (l & 0x2) != 0;
417 C = (l & 0x1) != 0;
418 printf ("N-%d ", N);
419 printf ("Z-%d ", Z);
420 printf ("V-%d ", V);
421 printf ("C-%d ", C);
422 if ((C | Z) == 0)
423 printf ("u> ");
424 if ((C | Z) == 1)
425 printf ("u<= ");
426 if ((C == 0))
427 printf ("u>= ");
428 if (C == 1)
429 printf ("u< ");
430 if (Z == 0)
431 printf ("!= ");
432 if (Z == 1)
433 printf ("== ");
434 if ((N ^ V) == 0)
435 printf (">= ");
436 if ((N ^ V) == 1)
437 printf ("< ");
438 if ((Z | (N ^ V)) == 0)
439 printf ("> ");
440 if ((Z | (N ^ V)) == 1)
441 printf ("<= ");
442 }
443}
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