Based on patches from H.J. Lu <hjl@nynexst.com>:
[deliverable/binutils-gdb.git] / gdb / w65-tdep.c
1 /* Target-machine dependent code for WDC-65816, for GDB.
2 Copyright (C) 1995 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
25 #include "defs.h"
26 #include "frame.h"
27 #include "obstack.h"
28 #include "symtab.h"
29 #include "gdbcmd.h"
30 #include "gdbtypes.h"
31 #include "dis-asm.h"
32
33
34 /* Return the saved PC from this frame. */
35
36
37 CORE_ADDR
38 w65_frame_saved_pc (frame)
39 struct frame_info *frame;
40 {
41 return (read_memory_integer (frame->frame + 2, 4) & 0xffffff);
42 }
43
44 CORE_ADDR
45 addr_bits_remove (x)
46 CORE_ADDR x;
47 {
48 return x;
49 }
50
51 read_memory_pointer (x)
52 CORE_ADDR x;
53 {
54 return read_memory_integer (ADDR_BITS_REMOVE (x), 4);
55 }
56
57 init_frame_pc ()
58 {
59 abort ();
60 }
61
62 void
63 w65_push_dummy_frame ()
64 {
65 abort ();
66 }
67
68 /* Put here the code to store, into a struct frame_saved_regs,
69 the addresses of the saved registers of frame described by FRAME_INFO.
70 This includes special registers such as pc and fp saved in special
71 ways in the stack frame. sp is even more special:
72 the address we return for it IS the sp for the next frame.
73
74 We cache the result of doing this in the frame_cache_obstack, since
75 it is fairly expensive. */
76
77 void
78 frame_find_saved_regs (fip, fsrp)
79 struct frame_info *fip;
80 struct frame_saved_regs *fsrp;
81 {
82 int locals;
83 CORE_ADDR pc;
84 CORE_ADDR adr;
85 int i;
86
87 memset (fsrp, 0, sizeof *fsrp);
88 }
89
90 int
91 saved_pc_after_call ()
92 {
93 int sp = read_register (SP_REGNUM);
94 int val = read_memory_integer (sp + 1, 4);
95 return ADDR_BITS_REMOVE (val);
96 }
97
98
99 extract_return_value (type, regbuf, valbuf)
100 struct type *type;
101 char *regbuf;
102 char *valbuf;
103 {
104 int b;
105 int len = TYPE_LENGTH (type);
106
107 for (b = 0; b < len; b += 2)
108 {
109 int todo = len - b;
110 if (todo > 2)
111 todo = 2;
112 memcpy (valbuf + b, regbuf + b, todo);
113 }
114 }
115
116 void
117 write_return_value (type, valbuf)
118 struct type *type;
119 char *valbuf;
120 {
121 int reg;
122 int len;
123 for (len = 0; len < TYPE_LENGTH (type); len += 2)
124 {
125 write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
126 }
127 }
128
129 void
130 store_struct_return (addr, sp)
131 CORE_ADDR addr;
132 CORE_ADDR sp;
133 {
134 write_register (2, addr);
135 }
136
137 void
138 w65_pop_frame ()
139 {
140 }
141
142 init_extra_frame_info ()
143 {
144 }
145
146 pop_frame ()
147 {
148 }
149
150 w65_frame_chain (thisframe)
151 struct frame_info *thisframe;
152 {
153 return 0xffff & read_memory_integer ((thisframe)->frame, 2);
154 }
155
156 static int
157 gb (x)
158 {
159 return read_memory_integer (x, 1) & 0xff;
160 }
161
162 extern CORE_ADDR
163 w65_skip_prologue (pc)
164 CORE_ADDR pc;
165 {
166 CORE_ADDR too_far = pc + 20;
167
168 /* looking for bits of the prologue, we can expect to
169 see this in a frameful function:
170
171 stack adjust:
172
173 3B tsc
174 1A inc a
175 18 clc
176 69E2FF adc #0xffe2
177 3A dec a
178 1B tcs
179 1A inc a
180
181 link:
182
183 A500 lda <r15
184 48 pha
185 3B tsc
186 1a inc a
187 8500 sta <r15
188
189 */
190
191 #define TSC 0x3b
192 #define TCS 0x1b
193 #define INCA 0x1a
194 #define PHA 0x48
195 #define LDADIR 0xa5
196 #define STADIR 0x85
197
198 /* Skip a stack adjust - any area between a tsc and tcs */
199 if (gb (pc) == TSC)
200 {
201 while (pc < too_far && gb (pc) != TCS)
202 {
203 pc++;
204 }
205 pc++;
206 /* Skip a stupid inc a */
207 if (gb (pc) == INCA)
208 pc++;
209
210 }
211 /* Stack adjust can also be done with n pha's */
212 while (gb (pc) == PHA)
213 pc++;
214
215 /* Skip a link - that's a ld/ph/tsc/inc/sta */
216
217 if (gb (pc) == LDADIR
218 && gb (pc + 5) == STADIR
219 && gb (pc + 1) == gb (pc + 6)
220 && gb (pc + 2) == PHA
221 && gb (pc + 3) == TSC
222 && gb (pc + 4) == INCA)
223 {
224 pc += 7;
225 }
226
227 return pc;
228 }
229
230
231 register_raw_size (n)
232 {
233 return sim_reg_size (n);
234 }
235
236
237 void
238 print_register_hook (regno)
239 {
240 if (regno == P_REGNUM)
241 {
242 /* CCR register */
243
244 int C, Z, N, V, I, D, X, M;
245 unsigned char b[1];
246 unsigned char l;
247
248 read_relative_register_raw_bytes (regno, b);
249 l = b[0];
250 printf_unfiltered ("\t");
251 C = (l & 0x1) != 0;
252 Z = (l & 0x2) != 0;
253 I = (l & 0x4) != 0;
254 D = (l & 0x8) != 0;
255 X = (l & 0x10) != 0;
256 M = (l & 0x20) != 0;
257 V = (l & 0x40) != 0;
258 N = (l & 0x80) != 0;
259
260 printf_unfiltered ("N-%d ", N);
261 printf_unfiltered ("V-%d ", V);
262 printf_unfiltered ("M-%d ", M);
263 printf_unfiltered ("X-%d ", X);
264 printf_unfiltered ("D-%d ", D);
265 printf_unfiltered ("I-%d ", I);
266 printf_unfiltered ("Z-%d ", Z);
267 printf_unfiltered ("C-%d ", C);
268 if ((C | Z) == 0)
269 printf_unfiltered ("u> ");
270 if ((C | Z) == 1)
271 printf_unfiltered ("u<= ");
272 if ((C == 0))
273 printf_unfiltered ("u>= ");
274 if (C == 1)
275 printf_unfiltered ("u< ");
276 if (Z == 0)
277 printf_unfiltered ("!= ");
278 if (Z == 1)
279 printf_unfiltered ("== ");
280 if ((N ^ V) == 0)
281 printf_unfiltered (">= ");
282 if ((N ^ V) == 1)
283 printf_unfiltered ("< ");
284 if ((Z | (N ^ V)) == 0)
285 printf_unfiltered ("> ");
286 if ((Z | (N ^ V)) == 1)
287 printf_unfiltered ("<= ");
288 }
289 }
290
291 void
292 _initialize_w65_tdep ()
293 {
294 tm_print_insn = print_insn_w65;
295 }
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