1 /* Target-machine dependent code for Hitachi H8/300, for GDB.
2 Copyright (C) 1988, 1990, 1991 Free Software Foundation, Inc.
4 This file is part of GDB.
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.
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.
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. */
21 Contributed by Steve Chamberlain
32 #define UNSIGNED_SHORT(X) ((X) & 0xffff)
34 /* an easy to debug H8 stack frame looks like:
38 0x7905 nnnn mov.w #n,r5 or 0x1b87 subs #2,sp
43 #define IS_PUSH(x) ((x & 0xff00)==0x6d00)
44 #define IS_PUSH_FP(x) (x == 0x6df6)
45 #define IS_MOVE_FP(x) (x == 0x0d76)
46 #define IS_MOV_SP_FP(x) (x == 0x0d76)
47 #define IS_SUB2_SP(x) (x==0x1b87)
48 #define IS_MOVK_R5(x) (x==0x7905)
49 #define IS_SUB_R5SP(x) (x==0x1957)
50 CORE_ADDR examine_prologue ();
52 void frame_find_saved_regs ();
54 h8300_skip_prologue (start_pc)
60 w = read_memory_short (start_pc);
61 /* Skip past all push insns */
62 while (IS_PUSH_FP (w))
65 w = read_memory_short (start_pc);
68 /* Skip past a move to FP */
72 w = read_memory_short (start_pc);
75 /* Skip the stack adjust */
80 w = read_memory_short (start_pc);
85 w = read_memory_short (start_pc);
87 while (IS_SUB2_SP (w))
90 w = read_memory_short (start_pc);
98 print_insn (memaddr, stream)
102 /* Nothing is bigger than 8 bytes */
105 read_memory (memaddr, data, sizeof (data));
106 return print_insn_h8300 (memaddr, data, stream);
109 /* Given a GDB frame, determine the address of the calling function's frame.
110 This will be used to create a new GDB frame struct, and then
111 INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame.
113 For us, the frame address is its stack pointer value, so we look up
114 the function prologue to determine the caller's sp value, and return it. */
117 FRAME_CHAIN (thisframe)
121 frame_find_saved_regs (thisframe, (struct frame_saved_regs *) 0);
122 return thisframe->fsr->regs[SP_REGNUM];
125 /* Put here the code to store, into a struct frame_saved_regs,
126 the addresses of the saved registers of frame described by FRAME_INFO.
127 This includes special registers such as pc and fp saved in special
128 ways in the stack frame. sp is even more special:
129 the address we return for it IS the sp for the next frame.
131 We cache the result of doing this in the frame_cache_obstack, since
132 it is fairly expensive. */
135 frame_find_saved_regs (fi, fsr)
136 struct frame_info *fi;
137 struct frame_saved_regs *fsr;
139 register CORE_ADDR next_addr;
140 register CORE_ADDR *saved_regs;
142 register struct frame_saved_regs *cache_fsr;
143 extern struct obstack frame_cache_obstack;
145 struct symtab_and_line sal;
150 cache_fsr = (struct frame_saved_regs *)
151 obstack_alloc (&frame_cache_obstack,
152 sizeof (struct frame_saved_regs));
153 bzero (cache_fsr, sizeof (struct frame_saved_regs));
157 /* Find the start and end of the function prologue. If the PC
158 is in the function prologue, we only consider the part that
159 has executed already. */
161 ip = get_pc_function_start (fi->pc);
162 sal = find_pc_line (ip, 0);
163 limit = (sal.end && sal.end < fi->pc) ? sal.end : fi->pc;
165 /* This will fill in fields in *fi as well as in cache_fsr. */
166 examine_prologue (ip, limit, fi->frame, cache_fsr, fi);
173 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
174 is not the address of a valid instruction, the address of the next
175 instruction beyond ADDR otherwise. *PWORD1 receives the first word
176 of the instruction.*/
179 NEXT_PROLOGUE_INSN (addr, lim, pword1)
186 read_memory (addr, pword1, sizeof (*pword1));
187 SWAP_TARGET_AND_HOST (pword1, sizeof (short));
194 /* Examine the prologue of a function. `ip' points to the first instruction.
195 `limit' is the limit of the prologue (e.g. the addr of the first
196 linenumber, or perhaps the program counter if we're stepping through).
197 `frame_sp' is the stack pointer value in use in this frame.
198 `fsr' is a pointer to a frame_saved_regs structure into which we put
199 info about the registers saved by this frame.
200 `fi' is a struct frame_info pointer; we fill in various fields in it
201 to reflect the offsets of the arg pointer and the locals pointer. */
204 examine_prologue (ip, limit, after_prolog_fp, fsr, fi)
205 register CORE_ADDR ip;
206 register CORE_ADDR limit;
207 FRAME_ADDR after_prolog_fp;
208 struct frame_saved_regs *fsr;
209 struct frame_info *fi;
211 register CORE_ADDR next_ip;
217 register struct pic_prologue_code *pcode;
220 unsigned int reg_save_depth = 2; /* Number of things pushed onto
221 stack, starts at 2, 'cause the
222 PC is already there */
224 unsigned int auto_depth = 0; /* Number of bytes of autos */
226 char in_frame[8]; /* One for each reg */
228 memset (in_frame, 1, 8);
229 for (r = 0; r < 8; r++)
233 if (after_prolog_fp == 0)
235 after_prolog_fp = read_register (SP_REGNUM);
237 if (ip == 0 || ip & ~0xffff)
240 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
242 /* Skip over any fp push instructions */
243 fsr->regs[6] = after_prolog_fp;
244 while (next_ip && IS_PUSH_FP (insn_word))
248 in_frame[insn_word & 0x7] = reg_save_depth;
249 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
253 /* Is this a move into the fp */
254 if (next_ip && IS_MOV_SP_FP (insn_word))
257 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
261 /* Skip over any stack adjustment, happens either with a number of
262 sub#2,sp or a mov #x,r5 sub r5,sp */
264 if (next_ip && IS_SUB2_SP (insn_word))
266 while (next_ip && IS_SUB2_SP (insn_word))
270 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
275 if (next_ip && IS_MOVK_R5 (insn_word))
278 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
279 auto_depth += insn_word;
281 next_ip = NEXT_PROLOGUE_INSN (next_ip, limit, &insn_word);
282 auto_depth += insn_word;
286 /* Work out which regs are stored where */
287 while (next_ip && IS_PUSH (insn_word))
290 next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
291 fsr->regs[r] = after_prolog_fp + auto_depth;
295 /* The args are always reffed based from the stack pointer */
296 fi->args_pointer = after_prolog_fp;
297 /* Locals are always reffed based from the fp */
298 fi->locals_pointer = after_prolog_fp;
299 /* The PC is at a known place */
300 fi->from_pc = read_memory_short (after_prolog_fp + 2);
302 /* Rememeber any others too */
303 in_frame[PC_REGNUM] = 0;
306 /* We keep the old FP in the SP spot */
307 fsr->regs[SP_REGNUM] = (read_memory_short (fsr->regs[6]));
309 fsr->regs[SP_REGNUM] = after_prolog_fp + auto_depth;
315 init_extra_frame_info (fromleaf, fi)
317 struct frame_info *fi;
319 fi->fsr = 0; /* Not yet allocated */
320 fi->args_pointer = 0; /* Unknown */
321 fi->locals_pointer = 0; /* Unknown */
326 /* Return the saved PC from this frame.
328 If the frame has a memory copy of SRP_REGNUM, use that. If not,
329 just use the register SRP_REGNUM itself. */
332 frame_saved_pc (frame)
336 return frame->from_pc;
340 frame_locals_address (fi)
341 struct frame_info *fi;
343 if (!fi->locals_pointer)
345 struct frame_saved_regs ignore;
347 get_frame_saved_regs (fi, &ignore);
350 return fi->locals_pointer;
353 /* Return the address of the argument block for the frame
354 described by FI. Returns 0 if the address is unknown. */
357 frame_args_address (fi)
358 struct frame_info *fi;
360 if (!fi->args_pointer)
362 struct frame_saved_regs ignore;
364 get_frame_saved_regs (fi, &ignore);
368 return fi->args_pointer;
375 struct frame_saved_regs fsr;
376 struct frame_info *fi;
378 FRAME frame = get_current_frame ();
380 fi = get_frame_info (frame);
381 get_frame_saved_regs (fi, &fsr);
383 for (regnum = 0; regnum < 8; regnum++)
385 if (fsr.regs[regnum])
387 write_register (regnum, read_memory_short (fsr.regs[regnum]));
390 flush_cached_frames ();
391 set_current_frame (create_new_frame (read_register (FP_REGNUM),
399 print_register_hook (regno)
409 read_relative_register_raw_bytes (regno, b);
412 printf ("I-%d - ", (l & 0x80) != 0);
413 printf ("H-%d - ", (l & 0x20) != 0);
438 if ((Z | (N ^ V)) == 0)
440 if ((Z | (N ^ V)) == 1)