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1f46923f SC |
1 | /* Target-machine dependent code for Hitachi H8/300, for GDB. |
2 | Copyright (C) 1988, 1990, 1991 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GDB. | |
5 | ||
6 | This program 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 2 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
19 | ||
20 | /* | |
21 | Contributed by Steve Chamberlain | |
22 | sac@cygnus.com | |
23 | */ | |
24 | ||
400943fb | 25 | #include "defs.h" |
1f46923f SC |
26 | #include "frame.h" |
27 | #include "obstack.h" | |
28 | #include "symtab.h" | |
29 | #define UNSIGNED_SHORT(X) ((X) & 0xffff) | |
400943fb SC |
30 | |
31 | /* an easy to debug H8 stack frame looks like: | |
32 | 0x6df2 push r2 | |
33 | 0x6df3 push r3 | |
34 | 0x6df6 push r6 | |
35 | 0x mov.w r7,r6 | |
36 | subs stuff,sp mov.w #x,r5 | |
37 | subs r5,sp | |
38 | ||
39 | */ | |
1f46923f | 40 | |
400943fb | 41 | #define IS_PUSH(x) ((x & 0xff00)==0x6d00) |
1f46923f SC |
42 | #define IS_MOVE_FP(x) (x == 0x0d76) |
43 | #define IS_MOV_SP_FP(x) (x == 0x0d76) | |
44 | #define IS_SUB2_SP(x) (x==0x1b87) | |
45 | #define IS_MOVK_R5(x) (x==0x7905) | |
46 | CORE_ADDR examine_prologue(); | |
47 | ||
48 | void frame_find_saved_regs (); | |
400943fb SC |
49 | CORE_ADDR h8300_skip_prologue(start_pc) |
50 | CORE_ADDR start_pc; | |
0a8f9d31 | 51 | |
0a8f9d31 | 52 | { |
1f46923f | 53 | |
400943fb SC |
54 | /* Skip past all push insns */ |
55 | short int w; | |
0a8f9d31 | 56 | |
96743d3c | 57 | w = read_memory_short(start_pc); |
400943fb SC |
58 | while (IS_PUSH(w)) |
59 | { | |
60 | start_pc+=2; | |
96743d3c | 61 | w = read_memory_short(start_pc); |
400943fb | 62 | } |
0a8f9d31 | 63 | |
1f46923f SC |
64 | /* Skip past a move to FP */ |
65 | if (IS_MOVE_FP(w)) { | |
66 | start_pc +=2 ; | |
96743d3c | 67 | w = read_memory_short(start_pc); |
1f46923f SC |
68 | } |
69 | ||
70 | return start_pc; | |
0a8f9d31 SC |
71 | |
72 | } | |
73 | ||
1f46923f | 74 | |
400943fb SC |
75 | int |
76 | print_insn(memaddr, stream) | |
77 | CORE_ADDR memaddr; | |
78 | FILE *stream; | |
0a8f9d31 | 79 | { |
400943fb SC |
80 | /* Nothing is bigger than 8 bytes */ |
81 | char data[8]; | |
82 | read_memory (memaddr, data, sizeof(data)); | |
1f46923f | 83 | return print_insn_h8300(memaddr, data, stream); |
0a8f9d31 | 84 | } |
400943fb SC |
85 | |
86 | ||
1f46923f SC |
87 | /* Given a GDB frame, determine the address of the calling function's frame. |
88 | This will be used to create a new GDB frame struct, and then | |
89 | INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame. | |
90 | ||
91 | For us, the frame address is its stack pointer value, so we look up | |
92 | the function prologue to determine the caller's sp value, and return it. */ | |
93 | ||
94 | FRAME_ADDR | |
95 | FRAME_CHAIN (thisframe) | |
96 | FRAME thisframe; | |
97 | { | |
98 | ||
99 | frame_find_saved_regs (thisframe, (struct frame_saved_regs *) 0); | |
100 | return thisframe->fsr->regs[SP_REGNUM]; | |
101 | } | |
102 | ||
400943fb | 103 | |
1f46923f SC |
104 | |
105 | /* Put here the code to store, into a struct frame_saved_regs, | |
106 | the addresses of the saved registers of frame described by FRAME_INFO. | |
107 | This includes special registers such as pc and fp saved in special | |
108 | ways in the stack frame. sp is even more special: | |
109 | the address we return for it IS the sp for the next frame. | |
110 | ||
111 | We cache the result of doing this in the frame_cache_obstack, since | |
112 | it is fairly expensive. */ | |
113 | ||
114 | void | |
115 | frame_find_saved_regs (fi, fsr) | |
116 | struct frame_info *fi; | |
117 | struct frame_saved_regs *fsr; | |
118 | { | |
119 | register CORE_ADDR next_addr; | |
120 | register CORE_ADDR *saved_regs; | |
121 | register int regnum; | |
122 | register struct frame_saved_regs *cache_fsr; | |
123 | extern struct obstack frame_cache_obstack; | |
124 | CORE_ADDR ip; | |
125 | struct symtab_and_line sal; | |
126 | CORE_ADDR limit; | |
127 | ||
128 | if (!fi->fsr) | |
129 | { | |
130 | cache_fsr = (struct frame_saved_regs *) | |
131 | obstack_alloc (&frame_cache_obstack, | |
132 | sizeof (struct frame_saved_regs)); | |
133 | bzero (cache_fsr, sizeof (struct frame_saved_regs)); | |
134 | fi->fsr = cache_fsr; | |
135 | ||
136 | /* Find the start and end of the function prologue. If the PC | |
137 | is in the function prologue, we only consider the part that | |
138 | has executed already. */ | |
139 | ||
140 | ip = get_pc_function_start (fi->pc); | |
141 | sal = find_pc_line (ip, 0); | |
142 | limit = (sal.end && sal.end < fi->pc) ? sal.end: fi->pc; | |
143 | ||
144 | /* This will fill in fields in *fi as well as in cache_fsr. */ | |
145 | examine_prologue (ip, limit, fi->frame, cache_fsr, fi); | |
146 | } | |
147 | ||
148 | if (fsr) | |
149 | *fsr = *fi->fsr; | |
150 | } | |
400943fb | 151 | |
1f46923f SC |
152 | |
153 | /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or | |
154 | is not the address of a valid instruction, the address of the next | |
155 | instruction beyond ADDR otherwise. *PWORD1 receives the first word | |
156 | of the instruction.*/ | |
157 | ||
158 | ||
159 | CORE_ADDR | |
160 | NEXT_PROLOGUE_INSN(addr, lim, pword1) | |
161 | CORE_ADDR addr; | |
162 | CORE_ADDR lim; | |
163 | short *pword1; | |
164 | { | |
165 | if (addr < lim+8) | |
166 | { | |
167 | read_memory (addr, pword1, sizeof(*pword1)); | |
168 | SWAP_TARGET_AND_HOST (pword1, sizeof (short)); | |
169 | return addr + 2; | |
170 | } | |
171 | ||
172 | return 0; | |
173 | ||
174 | } | |
175 | ||
176 | /* Examine the prologue of a function. `ip' points to the first instruction. | |
177 | `limit' is the limit of the prologue (e.g. the addr of the first | |
178 | linenumber, or perhaps the program counter if we're stepping through). | |
179 | `frame_sp' is the stack pointer value in use in this frame. | |
180 | `fsr' is a pointer to a frame_saved_regs structure into which we put | |
181 | info about the registers saved by this frame. | |
182 | `fi' is a struct frame_info pointer; we fill in various fields in it | |
183 | to reflect the offsets of the arg pointer and the locals pointer. */ | |
184 | ||
185 | /* We will find two sorts of prologue, framefull and non framefull: | |
186 | ||
187 | push r2 | |
188 | push r3 | |
189 | push fp | |
190 | mov sp,fp | |
191 | stack_ad | |
192 | ||
193 | and | |
194 | push x | |
195 | push y | |
196 | stack_ad | |
197 | ||
198 | */ | |
199 | ||
200 | static CORE_ADDR | |
201 | examine_prologue (ip, limit, after_prolog_fp, fsr, fi) | |
202 | register CORE_ADDR ip; | |
203 | register CORE_ADDR limit; | |
204 | FRAME_ADDR after_prolog_fp; | |
205 | struct frame_saved_regs *fsr; | |
206 | struct frame_info *fi; | |
207 | { | |
208 | register CORE_ADDR next_ip; | |
209 | int r; | |
210 | int i; | |
211 | int have_fp = 0; | |
212 | ||
213 | register int src; | |
214 | register struct pic_prologue_code *pcode; | |
215 | INSN_WORD insn_word; | |
216 | int size, offset; | |
217 | unsigned int reg_save_depth = 2; /* Number of things pushed onto | |
218 | stack, starts at 2, 'cause the | |
219 | PC is already there */ | |
220 | ||
221 | unsigned int auto_depth = 0; /* Number of bytes of autos */ | |
222 | ||
223 | char in_frame[NUM_REGS]; /* One for each reg */ | |
224 | ||
225 | memset(in_frame, 1, NUM_REGS); | |
226 | ||
227 | if (after_prolog_fp == 0) { | |
228 | after_prolog_fp = read_register(SP_REGNUM); | |
229 | } | |
230 | if (ip == 0 || ip & ~0xffff) return 0; | |
231 | ||
232 | next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word); | |
233 | ||
234 | /* Skip over any push instructions, and remember where they were saved */ | |
235 | ||
236 | ||
237 | while (next_ip && IS_PUSH(insn_word)) | |
238 | { | |
239 | ip = next_ip; | |
240 | in_frame[insn_word & 0x7] = reg_save_depth; | |
241 | next_ip = NEXT_PROLOGUE_INSN(ip, limit, &insn_word); | |
242 | reg_save_depth +=2; | |
243 | ||
244 | } | |
245 | ||
246 | ||
247 | /* Is this a move into the fp */ | |
248 | if (next_ip && IS_MOV_SP_FP(insn_word)) | |
249 | { | |
250 | ip = next_ip; | |
251 | next_ip = NEXT_PROLOGUE_INSN(ip, limit, &insn_word); | |
252 | have_fp = 1; | |
253 | ||
254 | } | |
255 | ||
256 | ||
257 | /* Skip over any stack adjustment, happens either with a number of | |
258 | sub#2,sp or a mov #x,r5 sub r5,sp */ | |
259 | ||
260 | ||
261 | if (next_ip && IS_SUB2_SP(insn_word)) | |
262 | { | |
263 | while (next_ip && IS_SUB2_SP(insn_word)) | |
264 | { | |
265 | auto_depth +=2 ; | |
266 | ip = next_ip; | |
267 | next_ip = NEXT_PROLOGUE_INSN(ip, limit, &insn_word); | |
268 | } | |
269 | } | |
270 | else | |
271 | { | |
272 | if (next_ip && IS_MOVK_R5(insn_word)) | |
273 | { | |
274 | ip = next_ip; | |
275 | next_ip = NEXT_PROLOGUE_INSN(ip, limit, &insn_word); | |
276 | auto_depth += insn_word; | |
277 | ip +=4; | |
278 | ||
279 | } | |
280 | } | |
281 | ||
282 | ||
283 | ||
284 | /* The args are always reffed based from the stack pointer */ | |
285 | fi->args_pointer = after_prolog_fp - auto_depth; | |
286 | /* Locals are always reffed based from the fp */ | |
287 | fi->locals_pointer = after_prolog_fp ; | |
288 | /* The PC is at a known place */ | |
96743d3c | 289 | fi->from_pc = read_memory_short(after_prolog_fp + reg_save_depth-2 ); |
1f46923f SC |
290 | |
291 | ||
292 | /* Rememeber any others too */ | |
293 | ||
294 | in_frame[PC_REGNUM] = 0; | |
295 | ||
296 | for (r = 0; r < NUM_REGS; r++) | |
297 | { | |
298 | if (in_frame[r] != 1) | |
299 | { | |
300 | fsr->regs[r] = after_prolog_fp + reg_save_depth - in_frame[r] -2; | |
301 | } | |
302 | else | |
303 | { | |
304 | fsr->regs[r] = 0; | |
305 | } | |
306 | } | |
307 | if (have_fp) | |
308 | /* We keep the old FP in the SP spot */ | |
96743d3c | 309 | fsr->regs[SP_REGNUM] = (read_memory_short(fsr->regs[6])) ; |
1f46923f SC |
310 | else |
311 | fsr->regs[SP_REGNUM] = after_prolog_fp + reg_save_depth; | |
312 | ||
313 | return (ip); | |
314 | } | |
315 | ||
316 | void | |
317 | init_extra_frame_info (fromleaf, fi) | |
318 | int fromleaf; | |
319 | struct frame_info *fi; | |
320 | { | |
321 | fi->fsr = 0; /* Not yet allocated */ | |
322 | fi->args_pointer = 0; /* Unknown */ | |
323 | fi->locals_pointer = 0; /* Unknown */ | |
324 | fi->from_pc = 0; | |
325 | ||
326 | } | |
327 | /* Return the saved PC from this frame. | |
328 | ||
329 | If the frame has a memory copy of SRP_REGNUM, use that. If not, | |
330 | just use the register SRP_REGNUM itself. */ | |
331 | ||
332 | CORE_ADDR | |
333 | frame_saved_pc (frame) | |
334 | FRAME frame; | |
335 | ||
336 | { | |
337 | return frame->from_pc; | |
338 | } | |
339 | ||
340 | ||
341 | CORE_ADDR | |
342 | frame_locals_address (fi) | |
343 | struct frame_info *fi; | |
344 | { | |
345 | if (!fi->locals_pointer) | |
346 | { | |
347 | struct frame_saved_regs ignore; | |
348 | get_frame_saved_regs(fi, &ignore); | |
349 | ||
350 | } | |
351 | return fi->locals_pointer; | |
352 | } | |
353 | ||
354 | /* Return the address of the argument block for the frame | |
355 | described by FI. Returns 0 if the address is unknown. */ | |
356 | ||
357 | CORE_ADDR | |
358 | frame_args_address (fi) | |
359 | struct frame_info *fi; | |
360 | { | |
361 | if (!fi->args_pointer) | |
362 | { | |
363 | struct frame_saved_regs ignore; | |
364 | get_frame_saved_regs(fi, &ignore); | |
365 | ||
366 | } | |
367 | ||
368 | return fi->args_pointer; | |
369 | } | |
370 | ||
371 | ||
372 | void h8300_pop_frame() | |
373 | { | |
374 | unsigned regnum; | |
375 | struct frame_saved_regs fsr; | |
376 | struct frame_info *fi; | |
377 | ||
378 | FRAME frame = get_current_frame(); | |
379 | fi = get_frame_info(frame); | |
380 | get_frame_saved_regs(fi, &fsr); | |
381 | ||
382 | for (regnum = 0; regnum < NUM_REGS; regnum ++) | |
383 | { | |
384 | if(fsr.regs[regnum]) | |
385 | { | |
96743d3c | 386 | write_register(regnum, read_memory_short (fsr.regs[regnum])); |
1f46923f SC |
387 | } |
388 | ||
389 | flush_cached_frames(); | |
390 | set_current_frame(create_new_frame(read_register(FP_REGNUM), | |
391 | read_pc())); | |
392 | ||
393 | } | |
394 | ||
395 | } |