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dd3b648e | 1 | /* Definitions to make GDB run on a vax under 4.2bsd. |
fbcb5095 | 2 | Copyright (C) 1986, 1987, 1989, 1991 Free Software Foundation, Inc. |
dd3b648e RP |
3 | |
4 | This file is part of GDB. | |
5 | ||
99a7de40 | 6 | This program is free software; you can redistribute it and/or modify |
dd3b648e | 7 | it under the terms of the GNU General Public License as published by |
99a7de40 JG |
8 | the Free Software Foundation; either version 2 of the License, or |
9 | (at your option) any later version. | |
dd3b648e | 10 | |
99a7de40 | 11 | This program is distributed in the hope that it will be useful, |
dd3b648e RP |
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 | |
99a7de40 JG |
17 | along with this program; if not, write to the Free Software |
18 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
dd3b648e RP |
19 | |
20 | /* There is one known bug with VAX support that I don't know how to | |
21 | fix: if you do a backtrace from a signal handler, you get something | |
22 | like: | |
23 | #0 0xbc in kill (592, 3) | |
24 | #1 0x7f in hand (...) (...) | |
25 | #2 0x7fffec7e in ?? (2, 0, 2147478112, 94) | |
26 | ^^ GDB doesn't know about sigtramp | |
27 | #3 0x7fffec70 in ?? (592, 2) | |
28 | ^^^^^^^^^^ wrong address | |
29 | #4 0xae in main (...) (...) | |
30 | ||
31 | when the correct backtrace (as given by adb) is: | |
32 | _kill(250,3) from _hand+21 | |
33 | _hand(2,0,7fffea60,5e) from 7fffec7e | |
34 | sigtramp(2,0,7fffea60,5e) from _kill+4 | |
35 | _kill(250,2) from _main+2e | |
36 | _main(1,7fffeac4,7fffeacc) from start+3d | |
37 | ||
38 | If anyone knows enough about VAX BSD to fix this, please send the | |
39 | fix to [email protected]. */ | |
40 | ||
41 | #define TARGET_BYTE_ORDER LITTLE_ENDIAN | |
42 | ||
43 | /* Define this if the C compiler puts an underscore at the front | |
44 | of external names before giving them to the linker. */ | |
45 | ||
46 | #define NAMES_HAVE_UNDERSCORE | |
47 | ||
dd3b648e RP |
48 | /* Offset from address of function to start of its code. |
49 | Zero on most machines. */ | |
50 | ||
51 | #define FUNCTION_START_OFFSET 2 | |
52 | ||
53 | /* Advance PC across any function entry prologue instructions | |
54 | to reach some "real" code. */ | |
55 | ||
56 | #define SKIP_PROLOGUE(pc) \ | |
57 | { register int op = (unsigned char) read_memory_integer (pc, 1); \ | |
58 | if (op == 0x11) pc += 2; /* skip brb */ \ | |
59 | if (op == 0x31) pc += 3; /* skip brw */ \ | |
60 | if (op == 0xC2 && \ | |
61 | ((unsigned char) read_memory_integer (pc+2, 1)) == 0x5E) \ | |
62 | pc += 3; /* skip subl2 */ \ | |
63 | if (op == 0x9E && \ | |
64 | ((unsigned char) read_memory_integer (pc+1, 1)) == 0xAE && \ | |
65 | ((unsigned char) read_memory_integer(pc+3, 1)) == 0x5E) \ | |
66 | pc += 4; /* skip movab */ \ | |
67 | if (op == 0x9E && \ | |
68 | ((unsigned char) read_memory_integer (pc+1, 1)) == 0xCE && \ | |
69 | ((unsigned char) read_memory_integer(pc+4, 1)) == 0x5E) \ | |
70 | pc += 5; /* skip movab */ \ | |
71 | if (op == 0x9E && \ | |
72 | ((unsigned char) read_memory_integer (pc+1, 1)) == 0xEE && \ | |
73 | ((unsigned char) read_memory_integer(pc+6, 1)) == 0x5E) \ | |
74 | pc += 7; /* skip movab */ \ | |
75 | } | |
76 | ||
77 | /* Immediately after a function call, return the saved pc. | |
78 | Can't always go through the frames for this because on some machines | |
79 | the new frame is not set up until the new function executes | |
80 | some instructions. */ | |
81 | ||
82 | #define SAVED_PC_AFTER_CALL(frame) FRAME_SAVED_PC(frame) | |
83 | ||
84 | #define TARGET_UPAGES 10 | |
85 | #define TARGET_NBPG 512 | |
86 | #define STACK_END_ADDR (0x80000000 - (TARGET_UPAGES * TARGET_NBPG)) | |
87 | ||
88 | /* On the VAX, sigtramp is in the u area. Can't check the exact | |
89 | addresses because for cross-debugging we don't have VAX include | |
90 | files around. This should be close enough. */ | |
91 | #define IN_SIGTRAMP(pc, name) ((pc) >= STACK_END_ADDR && (pc < 0x80000000)) | |
92 | ||
93 | /* Stack grows downward. */ | |
94 | ||
95 | #define INNER_THAN < | |
96 | ||
97 | /* Sequence of bytes for breakpoint instruction. */ | |
98 | ||
99 | #define BREAKPOINT {3} | |
100 | ||
101 | /* Amount PC must be decremented by after a breakpoint. | |
102 | This is often the number of bytes in BREAKPOINT | |
103 | but not always. */ | |
104 | ||
105 | #define DECR_PC_AFTER_BREAK 0 | |
106 | ||
107 | /* Nonzero if instruction at PC is a return instruction. */ | |
108 | ||
109 | #define ABOUT_TO_RETURN(pc) (read_memory_integer (pc, 1) == 04) | |
110 | ||
111 | /* Return 1 if P points to an invalid floating point value. | |
112 | LEN is the length in bytes -- not relevant on the Vax. */ | |
113 | ||
114 | #define INVALID_FLOAT(p, len) ((*(short *) p & 0xff80) == 0x8000) | |
115 | ||
116 | /* Say how long (ordinary) registers are. */ | |
117 | ||
118 | #define REGISTER_TYPE long | |
119 | ||
120 | /* Number of machine registers */ | |
121 | ||
122 | #define NUM_REGS 17 | |
123 | ||
124 | /* Initializer for an array of names of registers. | |
125 | There should be NUM_REGS strings in this initializer. */ | |
126 | ||
127 | #define REGISTER_NAMES {"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc", "ps"} | |
128 | ||
129 | /* Register numbers of various important registers. | |
130 | Note that some of these values are "real" register numbers, | |
131 | and correspond to the general registers of the machine, | |
132 | and some are "phony" register numbers which are too large | |
133 | to be actual register numbers as far as the user is concerned | |
134 | but do serve to get the desired values when passed to read_register. */ | |
135 | ||
136 | #define AP_REGNUM 12 | |
137 | #define FP_REGNUM 13 /* Contains address of executing stack frame */ | |
138 | #define SP_REGNUM 14 /* Contains address of top of stack */ | |
139 | #define PC_REGNUM 15 /* Contains program counter */ | |
140 | #define PS_REGNUM 16 /* Contains processor status */ | |
141 | ||
142 | /* Total amount of space needed to store our copies of the machine's | |
143 | register state, the array `registers'. */ | |
144 | #define REGISTER_BYTES (17*4) | |
145 | ||
146 | /* Index within `registers' of the first byte of the space for | |
147 | register N. */ | |
148 | ||
149 | #define REGISTER_BYTE(N) ((N) * 4) | |
150 | ||
151 | /* Number of bytes of storage in the actual machine representation | |
152 | for register N. On the vax, all regs are 4 bytes. */ | |
153 | ||
154 | #define REGISTER_RAW_SIZE(N) 4 | |
155 | ||
156 | /* Number of bytes of storage in the program's representation | |
157 | for register N. On the vax, all regs are 4 bytes. */ | |
158 | ||
159 | #define REGISTER_VIRTUAL_SIZE(N) 4 | |
160 | ||
161 | /* Largest value REGISTER_RAW_SIZE can have. */ | |
162 | ||
163 | #define MAX_REGISTER_RAW_SIZE 4 | |
164 | ||
165 | /* Largest value REGISTER_VIRTUAL_SIZE can have. */ | |
166 | ||
167 | #define MAX_REGISTER_VIRTUAL_SIZE 4 | |
168 | ||
169 | /* Nonzero if register N requires conversion | |
170 | from raw format to virtual format. */ | |
171 | ||
172 | #define REGISTER_CONVERTIBLE(N) 0 | |
173 | ||
174 | /* Convert data from raw format for register REGNUM | |
175 | to virtual format for register REGNUM. */ | |
176 | ||
177 | #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO) \ | |
178 | bcopy ((FROM), (TO), 4); | |
179 | ||
180 | /* Convert data from virtual format for register REGNUM | |
181 | to raw format for register REGNUM. */ | |
182 | ||
183 | #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO) \ | |
184 | bcopy ((FROM), (TO), 4); | |
185 | ||
186 | /* Return the GDB type object for the "standard" data type | |
187 | of data in register N. */ | |
188 | ||
189 | #define REGISTER_VIRTUAL_TYPE(N) builtin_type_int | |
190 | ||
191 | /* Store the address of the place in which to copy the structure the | |
192 | subroutine will return. This is called from call_function. */ | |
193 | ||
194 | #define STORE_STRUCT_RETURN(ADDR, SP) \ | |
195 | { write_register (1, (ADDR)); } | |
196 | ||
197 | /* Extract from an array REGBUF containing the (raw) register state | |
198 | a function return value of type TYPE, and copy that, in virtual format, | |
199 | into VALBUF. */ | |
200 | ||
201 | #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \ | |
202 | bcopy (REGBUF, VALBUF, TYPE_LENGTH (TYPE)) | |
203 | ||
204 | /* Write into appropriate registers a function return value | |
205 | of type TYPE, given in virtual format. */ | |
206 | ||
207 | #define STORE_RETURN_VALUE(TYPE,VALBUF) \ | |
208 | write_register_bytes (0, VALBUF, TYPE_LENGTH (TYPE)) | |
209 | ||
210 | /* Extract from an array REGBUF containing the (raw) register state | |
211 | the address in which a function should return its structure value, | |
212 | as a CORE_ADDR (or an expression that can be used as one). */ | |
213 | ||
214 | #define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF) (*(int *)(REGBUF)) | |
215 | ||
216 | \f | |
217 | /* Describe the pointer in each stack frame to the previous stack frame | |
218 | (its caller). */ | |
219 | ||
220 | /* FRAME_CHAIN takes a frame's nominal address | |
221 | and produces the frame's chain-pointer. | |
222 | ||
223 | FRAME_CHAIN_COMBINE takes the chain pointer and the frame's nominal address | |
224 | and produces the nominal address of the caller frame. | |
225 | ||
226 | However, if FRAME_CHAIN_VALID returns zero, | |
227 | it means the given frame is the outermost one and has no caller. | |
228 | In that case, FRAME_CHAIN_COMBINE is not used. */ | |
229 | ||
230 | /* In the case of the Vax, the frame's nominal address is the FP value, | |
231 | and 12 bytes later comes the saved previous FP value as a 4-byte word. */ | |
232 | ||
233 | #define FRAME_CHAIN(thisframe) \ | |
234 | (outside_startup_file ((thisframe)->pc) ? \ | |
235 | read_memory_integer ((thisframe)->frame + 12, 4) :\ | |
236 | 0) | |
237 | ||
238 | #define FRAME_CHAIN_VALID(chain, thisframe) \ | |
239 | (chain != 0 && (outside_startup_file (FRAME_SAVED_PC (thisframe)))) | |
240 | ||
241 | #define FRAME_CHAIN_COMBINE(chain, thisframe) (chain) | |
242 | ||
243 | /* Define other aspects of the stack frame. */ | |
244 | ||
245 | /* A macro that tells us whether the function invocation represented | |
246 | by FI does not have a frame on the stack associated with it. If it | |
247 | does not, FRAMELESS is set to 1, else 0. */ | |
248 | /* On the vax, all functions have frames. */ | |
249 | #define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) {(FRAMELESS) = 0;} | |
250 | ||
251 | /* Saved Pc. */ | |
252 | ||
253 | #define FRAME_SAVED_PC(FRAME) (read_memory_integer ((FRAME)->frame + 16, 4)) | |
254 | ||
255 | /* Cannot find the AP register value directly from the FP value. Must | |
256 | find it saved in the frame called by this one, or in the AP | |
257 | register for the innermost frame. However, there is no way to tell | |
258 | the difference between the innermost frame and a frame for which we | |
259 | just don't know the frame that it called (e.g. "info frame | |
260 | 0x7ffec789"). For the sake of argument suppose that the stack is | |
261 | somewhat trashed (which is one reason that "info frame" exists). | |
262 | So return 0 (indicating we don't know the address of | |
263 | the arglist) if we don't know what frame this frame calls. */ | |
264 | #define FRAME_ARGS_ADDRESS_CORRECT(fi) \ | |
265 | (((fi)->next_frame \ | |
266 | ? read_memory_integer ((fi)->next_frame + 8, 4) \ | |
267 | : /* read_register (AP_REGNUM) */ 0)) | |
268 | ||
269 | /* In most of GDB, getting the args address is too important to | |
270 | just say "I don't know". This is sometimes wrong for functions | |
271 | that aren't on top of the stack, but c'est la vie. */ | |
272 | #define FRAME_ARGS_ADDRESS(fi) \ | |
273 | (((fi)->next_frame \ | |
274 | ? read_memory_integer ((fi)->next_frame + 8, 4) \ | |
275 | : read_register (AP_REGNUM) /* 0 */)) | |
276 | ||
277 | #define FRAME_LOCALS_ADDRESS(fi) ((fi)->frame) | |
278 | ||
279 | /* Return number of args passed to a frame. | |
280 | Can return -1, meaning no way to tell. */ | |
281 | ||
282 | #define FRAME_NUM_ARGS(numargs, fi) \ | |
283 | { numargs = (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1)); } | |
284 | ||
285 | /* Return number of bytes at start of arglist that are not really args. */ | |
286 | ||
287 | #define FRAME_ARGS_SKIP 4 | |
288 | ||
289 | /* Put here the code to store, into a struct frame_saved_regs, | |
290 | the addresses of the saved registers of frame described by FRAME_INFO. | |
291 | This includes special registers such as pc and fp saved in special | |
292 | ways in the stack frame. sp is even more special: | |
293 | the address we return for it IS the sp for the next frame. */ | |
294 | ||
295 | #define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs) \ | |
296 | { register int regnum; \ | |
297 | register int regmask = read_memory_integer ((frame_info)->frame+4, 4) >> 16; \ | |
298 | register CORE_ADDR next_addr; \ | |
299 | bzero (&frame_saved_regs, sizeof frame_saved_regs); \ | |
300 | next_addr = (frame_info)->frame + 16; \ | |
301 | /* Regmask's low bit is for register 0, \ | |
302 | which is the first one that would be pushed. */ \ | |
303 | for (regnum = 0; regnum < 12; regnum++, regmask >>= 1) \ | |
304 | (frame_saved_regs).regs[regnum] = (regmask & 1) ? (next_addr += 4) : 0; \ | |
305 | (frame_saved_regs).regs[SP_REGNUM] = next_addr + 4; \ | |
306 | if (read_memory_integer ((frame_info)->frame + 4, 4) & 0x20000000) \ | |
307 | (frame_saved_regs).regs[SP_REGNUM] += 4 + 4 * read_memory_integer (next_addr + 4, 4); \ | |
308 | (frame_saved_regs).regs[PC_REGNUM] = (frame_info)->frame + 16; \ | |
309 | (frame_saved_regs).regs[FP_REGNUM] = (frame_info)->frame + 12; \ | |
310 | (frame_saved_regs).regs[AP_REGNUM] = (frame_info)->frame + 8; \ | |
311 | (frame_saved_regs).regs[PS_REGNUM] = (frame_info)->frame + 4; \ | |
312 | } | |
313 | \f | |
314 | /* Things needed for making the inferior call functions. */ | |
315 | ||
316 | /* Push an empty stack frame, to record the current PC, etc. */ | |
317 | ||
318 | #define PUSH_DUMMY_FRAME \ | |
319 | { register CORE_ADDR sp = read_register (SP_REGNUM);\ | |
320 | register int regnum; \ | |
321 | sp = push_word (sp, 0); /* arglist */ \ | |
322 | for (regnum = 11; regnum >= 0; regnum--) \ | |
323 | sp = push_word (sp, read_register (regnum)); \ | |
324 | sp = push_word (sp, read_register (PC_REGNUM)); \ | |
325 | sp = push_word (sp, read_register (FP_REGNUM)); \ | |
326 | sp = push_word (sp, read_register (AP_REGNUM)); \ | |
327 | sp = push_word (sp, (read_register (PS_REGNUM) & 0xffef) \ | |
328 | + 0x2fff0000); \ | |
329 | sp = push_word (sp, 0); \ | |
330 | write_register (SP_REGNUM, sp); \ | |
331 | write_register (FP_REGNUM, sp); \ | |
332 | write_register (AP_REGNUM, sp + 17 * sizeof (int)); } | |
333 | ||
334 | /* Discard from the stack the innermost frame, restoring all registers. */ | |
335 | ||
336 | #define POP_FRAME \ | |
337 | { register CORE_ADDR fp = read_register (FP_REGNUM); \ | |
338 | register int regnum; \ | |
339 | register int regmask = read_memory_integer (fp + 4, 4); \ | |
340 | write_register (PS_REGNUM, \ | |
341 | (regmask & 0xffff) \ | |
342 | | (read_register (PS_REGNUM) & 0xffff0000)); \ | |
343 | write_register (PC_REGNUM, read_memory_integer (fp + 16, 4)); \ | |
344 | write_register (FP_REGNUM, read_memory_integer (fp + 12, 4)); \ | |
345 | write_register (AP_REGNUM, read_memory_integer (fp + 8, 4)); \ | |
346 | fp += 16; \ | |
347 | for (regnum = 0; regnum < 12; regnum++) \ | |
348 | if (regmask & (0x10000 << regnum)) \ | |
349 | write_register (regnum, read_memory_integer (fp += 4, 4)); \ | |
350 | fp = fp + 4 + ((regmask >> 30) & 3); \ | |
351 | if (regmask & 0x20000000) \ | |
352 | { regnum = read_memory_integer (fp, 4); \ | |
353 | fp += (regnum + 1) * 4; } \ | |
354 | write_register (SP_REGNUM, fp); \ | |
355 | flush_cached_frames (); \ | |
356 | set_current_frame (create_new_frame (read_register (FP_REGNUM),\ | |
357 | read_pc ())); } | |
358 | ||
359 | /* This sequence of words is the instructions | |
360 | calls #69, @#32323232 | |
361 | bpt | |
362 | Note this is 8 bytes. */ | |
363 | ||
364 | #define CALL_DUMMY {0x329f69fb, 0x03323232} | |
365 | ||
366 | #define CALL_DUMMY_START_OFFSET 0 /* Start execution at beginning of dummy */ | |
367 | ||
368 | /* Insert the specified number of args and function address | |
369 | into a call sequence of the above form stored at DUMMYNAME. */ | |
370 | ||
371 | #define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p) \ | |
372 | { *((char *) dummyname + 1) = nargs; \ | |
373 | *(int *)((char *) dummyname + 3) = fun; } |