| 1 | /* Definitions to make GDB run on a vax under 4.2bsd. |
| 2 | Copyright (C) 1986, 1987, 1989, 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 | /* 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 bug-gdb@prep.ai.mit.edu. */ |
| 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 | |
| 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 | /* In the case of the Vax, the frame's nominal address is the FP value, |
| 224 | and 12 bytes later comes the saved previous FP value as a 4-byte word. */ |
| 225 | |
| 226 | #define FRAME_CHAIN(thisframe) \ |
| 227 | (!inside_entry_file ((thisframe)->pc) ? \ |
| 228 | read_memory_integer ((thisframe)->frame + 12, 4) :\ |
| 229 | 0) |
| 230 | |
| 231 | /* Define other aspects of the stack frame. */ |
| 232 | |
| 233 | /* A macro that tells us whether the function invocation represented |
| 234 | by FI does not have a frame on the stack associated with it. If it |
| 235 | does not, FRAMELESS is set to 1, else 0. */ |
| 236 | /* On the vax, all functions have frames. */ |
| 237 | #define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) {(FRAMELESS) = 0;} |
| 238 | |
| 239 | /* Saved Pc. */ |
| 240 | |
| 241 | #define FRAME_SAVED_PC(FRAME) (read_memory_integer ((FRAME)->frame + 16, 4)) |
| 242 | |
| 243 | /* Cannot find the AP register value directly from the FP value. Must |
| 244 | find it saved in the frame called by this one, or in the AP |
| 245 | register for the innermost frame. However, there is no way to tell |
| 246 | the difference between the innermost frame and a frame for which we |
| 247 | just don't know the frame that it called (e.g. "info frame |
| 248 | 0x7ffec789"). For the sake of argument suppose that the stack is |
| 249 | somewhat trashed (which is one reason that "info frame" exists). |
| 250 | So return 0 (indicating we don't know the address of |
| 251 | the arglist) if we don't know what frame this frame calls. */ |
| 252 | #define FRAME_ARGS_ADDRESS_CORRECT(fi) \ |
| 253 | (((fi)->next_frame \ |
| 254 | ? read_memory_integer ((fi)->next_frame + 8, 4) \ |
| 255 | : /* read_register (AP_REGNUM) */ 0)) |
| 256 | |
| 257 | /* In most of GDB, getting the args address is too important to |
| 258 | just say "I don't know". This is sometimes wrong for functions |
| 259 | that aren't on top of the stack, but c'est la vie. */ |
| 260 | #define FRAME_ARGS_ADDRESS(fi) \ |
| 261 | (((fi)->next_frame \ |
| 262 | ? read_memory_integer ((fi)->next_frame + 8, 4) \ |
| 263 | : read_register (AP_REGNUM) /* 0 */)) |
| 264 | |
| 265 | #define FRAME_LOCALS_ADDRESS(fi) ((fi)->frame) |
| 266 | |
| 267 | /* Return number of args passed to a frame. |
| 268 | Can return -1, meaning no way to tell. */ |
| 269 | |
| 270 | #define FRAME_NUM_ARGS(numargs, fi) \ |
| 271 | { numargs = (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1)); } |
| 272 | |
| 273 | /* Return number of bytes at start of arglist that are not really args. */ |
| 274 | |
| 275 | #define FRAME_ARGS_SKIP 4 |
| 276 | |
| 277 | /* Put here the code to store, into a struct frame_saved_regs, |
| 278 | the addresses of the saved registers of frame described by FRAME_INFO. |
| 279 | This includes special registers such as pc and fp saved in special |
| 280 | ways in the stack frame. sp is even more special: |
| 281 | the address we return for it IS the sp for the next frame. */ |
| 282 | |
| 283 | #define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs) \ |
| 284 | { register int regnum; \ |
| 285 | register int regmask = read_memory_integer ((frame_info)->frame+4, 4) >> 16; \ |
| 286 | register CORE_ADDR next_addr; \ |
| 287 | bzero (&frame_saved_regs, sizeof frame_saved_regs); \ |
| 288 | next_addr = (frame_info)->frame + 16; \ |
| 289 | /* Regmask's low bit is for register 0, \ |
| 290 | which is the first one that would be pushed. */ \ |
| 291 | for (regnum = 0; regnum < 12; regnum++, regmask >>= 1) \ |
| 292 | (frame_saved_regs).regs[regnum] = (regmask & 1) ? (next_addr += 4) : 0; \ |
| 293 | (frame_saved_regs).regs[SP_REGNUM] = next_addr + 4; \ |
| 294 | if (read_memory_integer ((frame_info)->frame + 4, 4) & 0x20000000) \ |
| 295 | (frame_saved_regs).regs[SP_REGNUM] += 4 + 4 * read_memory_integer (next_addr + 4, 4); \ |
| 296 | (frame_saved_regs).regs[PC_REGNUM] = (frame_info)->frame + 16; \ |
| 297 | (frame_saved_regs).regs[FP_REGNUM] = (frame_info)->frame + 12; \ |
| 298 | (frame_saved_regs).regs[AP_REGNUM] = (frame_info)->frame + 8; \ |
| 299 | (frame_saved_regs).regs[PS_REGNUM] = (frame_info)->frame + 4; \ |
| 300 | } |
| 301 | \f |
| 302 | /* Things needed for making the inferior call functions. */ |
| 303 | |
| 304 | /* Push an empty stack frame, to record the current PC, etc. */ |
| 305 | |
| 306 | #define PUSH_DUMMY_FRAME \ |
| 307 | { register CORE_ADDR sp = read_register (SP_REGNUM);\ |
| 308 | register int regnum; \ |
| 309 | sp = push_word (sp, 0); /* arglist */ \ |
| 310 | for (regnum = 11; regnum >= 0; regnum--) \ |
| 311 | sp = push_word (sp, read_register (regnum)); \ |
| 312 | sp = push_word (sp, read_register (PC_REGNUM)); \ |
| 313 | sp = push_word (sp, read_register (FP_REGNUM)); \ |
| 314 | sp = push_word (sp, read_register (AP_REGNUM)); \ |
| 315 | sp = push_word (sp, (read_register (PS_REGNUM) & 0xffef) \ |
| 316 | + 0x2fff0000); \ |
| 317 | sp = push_word (sp, 0); \ |
| 318 | write_register (SP_REGNUM, sp); \ |
| 319 | write_register (FP_REGNUM, sp); \ |
| 320 | write_register (AP_REGNUM, sp + 17 * sizeof (int)); } |
| 321 | |
| 322 | /* Discard from the stack the innermost frame, restoring all registers. */ |
| 323 | |
| 324 | #define POP_FRAME \ |
| 325 | { register CORE_ADDR fp = read_register (FP_REGNUM); \ |
| 326 | register int regnum; \ |
| 327 | register int regmask = read_memory_integer (fp + 4, 4); \ |
| 328 | write_register (PS_REGNUM, \ |
| 329 | (regmask & 0xffff) \ |
| 330 | | (read_register (PS_REGNUM) & 0xffff0000)); \ |
| 331 | write_register (PC_REGNUM, read_memory_integer (fp + 16, 4)); \ |
| 332 | write_register (FP_REGNUM, read_memory_integer (fp + 12, 4)); \ |
| 333 | write_register (AP_REGNUM, read_memory_integer (fp + 8, 4)); \ |
| 334 | fp += 16; \ |
| 335 | for (regnum = 0; regnum < 12; regnum++) \ |
| 336 | if (regmask & (0x10000 << regnum)) \ |
| 337 | write_register (regnum, read_memory_integer (fp += 4, 4)); \ |
| 338 | fp = fp + 4 + ((regmask >> 30) & 3); \ |
| 339 | if (regmask & 0x20000000) \ |
| 340 | { regnum = read_memory_integer (fp, 4); \ |
| 341 | fp += (regnum + 1) * 4; } \ |
| 342 | write_register (SP_REGNUM, fp); \ |
| 343 | flush_cached_frames (); \ |
| 344 | set_current_frame (create_new_frame (read_register (FP_REGNUM),\ |
| 345 | read_pc ())); } |
| 346 | |
| 347 | /* This sequence of words is the instructions |
| 348 | calls #69, @#32323232 |
| 349 | bpt |
| 350 | Note this is 8 bytes. */ |
| 351 | |
| 352 | #define CALL_DUMMY {0x329f69fb, 0x03323232} |
| 353 | |
| 354 | #define CALL_DUMMY_START_OFFSET 0 /* Start execution at beginning of dummy */ |
| 355 | |
| 356 | /* Insert the specified number of args and function address |
| 357 | into a call sequence of the above form stored at DUMMYNAME. */ |
| 358 | |
| 359 | #define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p) \ |
| 360 | { *((char *) dummyname + 1) = nargs; \ |
| 361 | *(int *)((char *) dummyname + 3) = fun; } |