1 /* Definitions to make GDB run on a vax under 4.2bsd.
2 Copyright (C) 1986, 1987, 1989 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. */
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
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 (...) (...)
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
38 If anyone knows enough about VAX BSD to fix this, please send the
39 fix to bug-gdb@prep.ai.mit.edu. */
41 #define TARGET_BYTE_ORDER LITTLE_ENDIAN
43 /* Define this if the C compiler puts an underscore at the front
44 of external names before giving them to the linker. */
46 #define NAMES_HAVE_UNDERSCORE
48 /* Debugger information will be in DBX format. */
50 #define READ_DBX_FORMAT
52 /* Offset from address of function to start of its code.
53 Zero on most machines. */
55 #define FUNCTION_START_OFFSET 2
57 /* Advance PC across any function entry prologue instructions
58 to reach some "real" code. */
60 #define SKIP_PROLOGUE(pc) \
61 { register int op = (unsigned char) read_memory_integer (pc, 1); \
62 if (op == 0x11) pc += 2; /* skip brb */ \
63 if (op == 0x31) pc += 3; /* skip brw */ \
65 ((unsigned char) read_memory_integer (pc+2, 1)) == 0x5E) \
66 pc += 3; /* skip subl2 */ \
68 ((unsigned char) read_memory_integer (pc+1, 1)) == 0xAE && \
69 ((unsigned char) read_memory_integer(pc+3, 1)) == 0x5E) \
70 pc += 4; /* skip movab */ \
72 ((unsigned char) read_memory_integer (pc+1, 1)) == 0xCE && \
73 ((unsigned char) read_memory_integer(pc+4, 1)) == 0x5E) \
74 pc += 5; /* skip movab */ \
76 ((unsigned char) read_memory_integer (pc+1, 1)) == 0xEE && \
77 ((unsigned char) read_memory_integer(pc+6, 1)) == 0x5E) \
78 pc += 7; /* skip movab */ \
81 /* Immediately after a function call, return the saved pc.
82 Can't always go through the frames for this because on some machines
83 the new frame is not set up until the new function executes
86 #define SAVED_PC_AFTER_CALL(frame) FRAME_SAVED_PC(frame)
88 #define TARGET_UPAGES 10
89 #define TARGET_NBPG 512
90 #define STACK_END_ADDR (0x80000000 - (TARGET_UPAGES * TARGET_NBPG))
92 /* On the VAX, sigtramp is in the u area. Can't check the exact
93 addresses because for cross-debugging we don't have VAX include
94 files around. This should be close enough. */
95 #define IN_SIGTRAMP(pc, name) ((pc) >= STACK_END_ADDR && (pc < 0x80000000))
97 /* Stack grows downward. */
101 /* Sequence of bytes for breakpoint instruction. */
103 #define BREAKPOINT {3}
105 /* Amount PC must be decremented by after a breakpoint.
106 This is often the number of bytes in BREAKPOINT
109 #define DECR_PC_AFTER_BREAK 0
111 /* Nonzero if instruction at PC is a return instruction. */
113 #define ABOUT_TO_RETURN(pc) (read_memory_integer (pc, 1) == 04)
115 /* Return 1 if P points to an invalid floating point value.
116 LEN is the length in bytes -- not relevant on the Vax. */
118 #define INVALID_FLOAT(p, len) ((*(short *) p & 0xff80) == 0x8000)
120 /* Say how long (ordinary) registers are. */
122 #define REGISTER_TYPE long
124 /* Number of machine registers */
128 /* Initializer for an array of names of registers.
129 There should be NUM_REGS strings in this initializer. */
131 #define REGISTER_NAMES {"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc", "ps"}
133 /* Register numbers of various important registers.
134 Note that some of these values are "real" register numbers,
135 and correspond to the general registers of the machine,
136 and some are "phony" register numbers which are too large
137 to be actual register numbers as far as the user is concerned
138 but do serve to get the desired values when passed to read_register. */
141 #define FP_REGNUM 13 /* Contains address of executing stack frame */
142 #define SP_REGNUM 14 /* Contains address of top of stack */
143 #define PC_REGNUM 15 /* Contains program counter */
144 #define PS_REGNUM 16 /* Contains processor status */
146 /* Total amount of space needed to store our copies of the machine's
147 register state, the array `registers'. */
148 #define REGISTER_BYTES (17*4)
150 /* Index within `registers' of the first byte of the space for
153 #define REGISTER_BYTE(N) ((N) * 4)
155 /* Number of bytes of storage in the actual machine representation
156 for register N. On the vax, all regs are 4 bytes. */
158 #define REGISTER_RAW_SIZE(N) 4
160 /* Number of bytes of storage in the program's representation
161 for register N. On the vax, all regs are 4 bytes. */
163 #define REGISTER_VIRTUAL_SIZE(N) 4
165 /* Largest value REGISTER_RAW_SIZE can have. */
167 #define MAX_REGISTER_RAW_SIZE 4
169 /* Largest value REGISTER_VIRTUAL_SIZE can have. */
171 #define MAX_REGISTER_VIRTUAL_SIZE 4
173 /* Nonzero if register N requires conversion
174 from raw format to virtual format. */
176 #define REGISTER_CONVERTIBLE(N) 0
178 /* Convert data from raw format for register REGNUM
179 to virtual format for register REGNUM. */
181 #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO) \
182 bcopy ((FROM), (TO), 4);
184 /* Convert data from virtual format for register REGNUM
185 to raw format for register REGNUM. */
187 #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO) \
188 bcopy ((FROM), (TO), 4);
190 /* Return the GDB type object for the "standard" data type
191 of data in register N. */
193 #define REGISTER_VIRTUAL_TYPE(N) builtin_type_int
195 /* Store the address of the place in which to copy the structure the
196 subroutine will return. This is called from call_function. */
198 #define STORE_STRUCT_RETURN(ADDR, SP) \
199 { write_register (1, (ADDR)); }
201 /* Extract from an array REGBUF containing the (raw) register state
202 a function return value of type TYPE, and copy that, in virtual format,
205 #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
206 bcopy (REGBUF, VALBUF, TYPE_LENGTH (TYPE))
208 /* Write into appropriate registers a function return value
209 of type TYPE, given in virtual format. */
211 #define STORE_RETURN_VALUE(TYPE,VALBUF) \
212 write_register_bytes (0, VALBUF, TYPE_LENGTH (TYPE))
214 /* Extract from an array REGBUF containing the (raw) register state
215 the address in which a function should return its structure value,
216 as a CORE_ADDR (or an expression that can be used as one). */
218 #define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF) (*(int *)(REGBUF))
221 /* Describe the pointer in each stack frame to the previous stack frame
224 /* FRAME_CHAIN takes a frame's nominal address
225 and produces the frame's chain-pointer.
227 FRAME_CHAIN_COMBINE takes the chain pointer and the frame's nominal address
228 and produces the nominal address of the caller frame.
230 However, if FRAME_CHAIN_VALID returns zero,
231 it means the given frame is the outermost one and has no caller.
232 In that case, FRAME_CHAIN_COMBINE is not used. */
234 /* In the case of the Vax, the frame's nominal address is the FP value,
235 and 12 bytes later comes the saved previous FP value as a 4-byte word. */
237 #define FRAME_CHAIN(thisframe) \
238 (outside_startup_file ((thisframe)->pc) ? \
239 read_memory_integer ((thisframe)->frame + 12, 4) :\
242 #define FRAME_CHAIN_VALID(chain, thisframe) \
243 (chain != 0 && (outside_startup_file (FRAME_SAVED_PC (thisframe))))
245 #define FRAME_CHAIN_COMBINE(chain, thisframe) (chain)
247 /* Define other aspects of the stack frame. */
249 /* A macro that tells us whether the function invocation represented
250 by FI does not have a frame on the stack associated with it. If it
251 does not, FRAMELESS is set to 1, else 0. */
252 /* On the vax, all functions have frames. */
253 #define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) {(FRAMELESS) = 0;}
257 #define FRAME_SAVED_PC(FRAME) (read_memory_integer ((FRAME)->frame + 16, 4))
259 /* Cannot find the AP register value directly from the FP value. Must
260 find it saved in the frame called by this one, or in the AP
261 register for the innermost frame. However, there is no way to tell
262 the difference between the innermost frame and a frame for which we
263 just don't know the frame that it called (e.g. "info frame
264 0x7ffec789"). For the sake of argument suppose that the stack is
265 somewhat trashed (which is one reason that "info frame" exists).
266 So return 0 (indicating we don't know the address of
267 the arglist) if we don't know what frame this frame calls. */
268 #define FRAME_ARGS_ADDRESS_CORRECT(fi) \
270 ? read_memory_integer ((fi)->next_frame + 8, 4) \
271 : /* read_register (AP_REGNUM) */ 0))
273 /* In most of GDB, getting the args address is too important to
274 just say "I don't know". This is sometimes wrong for functions
275 that aren't on top of the stack, but c'est la vie. */
276 #define FRAME_ARGS_ADDRESS(fi) \
278 ? read_memory_integer ((fi)->next_frame + 8, 4) \
279 : read_register (AP_REGNUM) /* 0 */))
281 #define FRAME_LOCALS_ADDRESS(fi) ((fi)->frame)
283 /* Return number of args passed to a frame.
284 Can return -1, meaning no way to tell. */
286 #define FRAME_NUM_ARGS(numargs, fi) \
287 { numargs = (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1)); }
289 /* Return number of bytes at start of arglist that are not really args. */
291 #define FRAME_ARGS_SKIP 4
293 /* Put here the code to store, into a struct frame_saved_regs,
294 the addresses of the saved registers of frame described by FRAME_INFO.
295 This includes special registers such as pc and fp saved in special
296 ways in the stack frame. sp is even more special:
297 the address we return for it IS the sp for the next frame. */
299 #define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs) \
300 { register int regnum; \
301 register int regmask = read_memory_integer ((frame_info)->frame+4, 4) >> 16; \
302 register CORE_ADDR next_addr; \
303 bzero (&frame_saved_regs, sizeof frame_saved_regs); \
304 next_addr = (frame_info)->frame + 16; \
305 /* Regmask's low bit is for register 0, \
306 which is the first one that would be pushed. */ \
307 for (regnum = 0; regnum < 12; regnum++, regmask >>= 1) \
308 (frame_saved_regs).regs[regnum] = (regmask & 1) ? (next_addr += 4) : 0; \
309 (frame_saved_regs).regs[SP_REGNUM] = next_addr + 4; \
310 if (read_memory_integer ((frame_info)->frame + 4, 4) & 0x20000000) \
311 (frame_saved_regs).regs[SP_REGNUM] += 4 + 4 * read_memory_integer (next_addr + 4, 4); \
312 (frame_saved_regs).regs[PC_REGNUM] = (frame_info)->frame + 16; \
313 (frame_saved_regs).regs[FP_REGNUM] = (frame_info)->frame + 12; \
314 (frame_saved_regs).regs[AP_REGNUM] = (frame_info)->frame + 8; \
315 (frame_saved_regs).regs[PS_REGNUM] = (frame_info)->frame + 4; \
318 /* Things needed for making the inferior call functions. */
320 /* Push an empty stack frame, to record the current PC, etc. */
322 #define PUSH_DUMMY_FRAME \
323 { register CORE_ADDR sp = read_register (SP_REGNUM);\
324 register int regnum; \
325 sp = push_word (sp, 0); /* arglist */ \
326 for (regnum = 11; regnum >= 0; regnum--) \
327 sp = push_word (sp, read_register (regnum)); \
328 sp = push_word (sp, read_register (PC_REGNUM)); \
329 sp = push_word (sp, read_register (FP_REGNUM)); \
330 sp = push_word (sp, read_register (AP_REGNUM)); \
331 sp = push_word (sp, (read_register (PS_REGNUM) & 0xffef) \
333 sp = push_word (sp, 0); \
334 write_register (SP_REGNUM, sp); \
335 write_register (FP_REGNUM, sp); \
336 write_register (AP_REGNUM, sp + 17 * sizeof (int)); }
338 /* Discard from the stack the innermost frame, restoring all registers. */
341 { register CORE_ADDR fp = read_register (FP_REGNUM); \
342 register int regnum; \
343 register int regmask = read_memory_integer (fp + 4, 4); \
344 write_register (PS_REGNUM, \
346 | (read_register (PS_REGNUM) & 0xffff0000)); \
347 write_register (PC_REGNUM, read_memory_integer (fp + 16, 4)); \
348 write_register (FP_REGNUM, read_memory_integer (fp + 12, 4)); \
349 write_register (AP_REGNUM, read_memory_integer (fp + 8, 4)); \
351 for (regnum = 0; regnum < 12; regnum++) \
352 if (regmask & (0x10000 << regnum)) \
353 write_register (regnum, read_memory_integer (fp += 4, 4)); \
354 fp = fp + 4 + ((regmask >> 30) & 3); \
355 if (regmask & 0x20000000) \
356 { regnum = read_memory_integer (fp, 4); \
357 fp += (regnum + 1) * 4; } \
358 write_register (SP_REGNUM, fp); \
359 flush_cached_frames (); \
360 set_current_frame (create_new_frame (read_register (FP_REGNUM),\
363 /* This sequence of words is the instructions
364 calls #69, @#32323232
366 Note this is 8 bytes. */
368 #define CALL_DUMMY {0x329f69fb, 0x03323232}
370 #define CALL_DUMMY_START_OFFSET 0 /* Start execution at beginning of dummy */
372 /* Insert the specified number of args and function address
373 into a call sequence of the above form stored at DUMMYNAME. */
375 #define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p) \
376 { *((char *) dummyname + 1) = nargs; \
377 *(int *)((char *) dummyname + 3) = fun; }
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