gdb/tm-vax.h

   1 /* Definitions to make GDB run on a vax under 4.2bsd.
   2    Copyright (C) 1986, 1987, 1989 Free Software Foundation, Inc.
   3
   4 This file is part of GDB.
   5
   6 GDB 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 1, or (at your option)
   9 any later version.
  10
  11 GDB 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 GDB; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 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 /* Debugger information will be in DBX format.  */
  49
  50 #define READ_DBX_FORMAT
  51
  52 /* Offset from address of function to start of its code.
  53    Zero on most machines.  */
  54
  55 #define FUNCTION_START_OFFSET 2
  56
  57 /* Advance PC across any function entry prologue instructions
  58    to reach some "real" code.  */
  59
  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 */                        \
  64   if (op == 0xC2 &&                                               \
  65       ((unsigned char) read_memory_integer (pc+2, 1)) == 0x5E)    \
  66     pc += 3;  /* skip subl2 */                                    \
  67   if (op == 0x9E &&                                               \
  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 */                                   \
  71   if (op == 0x9E &&                                               \
  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 */                                    \
  75   if (op == 0x9E &&                                               \
  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 */                                    \
  79 }
  80
  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
  84    some instructions.  */
  85
  86 #define SAVED_PC_AFTER_CALL(frame) FRAME_SAVED_PC(frame)
  87
  88 #define TARGET_UPAGES 10
  89 #define TARGET_NBPG 512
  90 #define STACK_END_ADDR (0x80000000 - (TARGET_UPAGES * TARGET_NBPG))
  91
  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))
  96
  97 /* Stack grows downward.  */
  98
  99 #define INNER_THAN <
 100
 101 /* Sequence of bytes for breakpoint instruction.  */
 102
 103 #define BREAKPOINT {3}
 104
 105 /* Amount PC must be decremented by after a breakpoint.
 106    This is often the number of bytes in BREAKPOINT
 107    but not always.  */
 108
 109 #define DECR_PC_AFTER_BREAK 0
 110
 111 /* Nonzero if instruction at PC is a return instruction.  */
 112
 113 #define ABOUT_TO_RETURN(pc) (read_memory_integer (pc, 1) == 04)
 114
 115 /* Return 1 if P points to an invalid floating point value.
 116    LEN is the length in bytes -- not relevant on the Vax.  */
 117
 118 #define INVALID_FLOAT(p, len) ((*(short *) p & 0xff80) == 0x8000)
 119
 120 /* Say how long (ordinary) registers are.  */
 121
 122 #define REGISTER_TYPE long
 123
 124 /* Number of machine registers */
 125
 126 #define NUM_REGS 17
 127
 128 /* Initializer for an array of names of registers.
 129    There should be NUM_REGS strings in this initializer.  */
 130
 131 #define REGISTER_NAMES {"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc", "ps"}
 132
 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.  */
 139
 140 #define AP_REGNUM 12
 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 */
 145
 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)
 149
 150 /* Index within `registers' of the first byte of the space for
 151    register N.  */
 152
 153 #define REGISTER_BYTE(N) ((N) * 4)
 154
 155 /* Number of bytes of storage in the actual machine representation
 156    for register N.  On the vax, all regs are 4 bytes.  */
 157
 158 #define REGISTER_RAW_SIZE(N) 4
 159
 160 /* Number of bytes of storage in the program's representation
 161    for register N.  On the vax, all regs are 4 bytes.  */
 162
 163 #define REGISTER_VIRTUAL_SIZE(N) 4
 164
 165 /* Largest value REGISTER_RAW_SIZE can have.  */
 166
 167 #define MAX_REGISTER_RAW_SIZE 4
 168
 169 /* Largest value REGISTER_VIRTUAL_SIZE can have.  */
 170
 171 #define MAX_REGISTER_VIRTUAL_SIZE 4
 172
 173 /* Nonzero if register N requires conversion
 174    from raw format to virtual format.  */
 175
 176 #define REGISTER_CONVERTIBLE(N) 0
 177
 178 /* Convert data from raw format for register REGNUM
 179    to virtual format for register REGNUM.  */
 180
 181 #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO)     \
 182   bcopy ((FROM), (TO), 4);
 183
 184 /* Convert data from virtual format for register REGNUM
 185    to raw format for register REGNUM.  */
 186
 187 #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO) \
 188   bcopy ((FROM), (TO), 4);
 189
 190 /* Return the GDB type object for the "standard" data type
 191    of data in register N.  */
 192
 193 #define REGISTER_VIRTUAL_TYPE(N) builtin_type_int
 194
 195 /* Store the address of the place in which to copy the structure the
 196    subroutine will return.  This is called from call_function. */
 197
 198 #define STORE_STRUCT_RETURN(ADDR, SP) \
 199   { write_register (1, (ADDR)); }
 200
 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,
 203    into VALBUF.  */
 204
 205 #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
 206   bcopy (REGBUF, VALBUF, TYPE_LENGTH (TYPE))
 207
 208 /* Write into appropriate registers a function return value
 209    of type TYPE, given in virtual format.  */
 210
 211 #define STORE_RETURN_VALUE(TYPE,VALBUF) \
 212   write_register_bytes (0, VALBUF, TYPE_LENGTH (TYPE))
 213
 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).  */
 217
 218 #define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF) (*(int *)(REGBUF))
 219
 220 \f
 221 /* Describe the pointer in each stack frame to the previous stack frame
 222    (its caller).  */
 223
 224 /* FRAME_CHAIN takes a frame's nominal address
 225    and produces the frame's chain-pointer.
 226
 227    FRAME_CHAIN_COMBINE takes the chain pointer and the frame's nominal address
 228    and produces the nominal address of the caller frame.
 229
 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.  */
 233
 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.  */
 236
 237 #define FRAME_CHAIN(thisframe)  \
 238   (outside_startup_file ((thisframe)->pc) ? \
 239    read_memory_integer ((thisframe)->frame + 12, 4) :\
 240    0)
 241
 242 #define FRAME_CHAIN_VALID(chain, thisframe) \
 243   (chain != 0 && (outside_startup_file (FRAME_SAVED_PC (thisframe))))
 244
 245 #define FRAME_CHAIN_COMBINE(chain, thisframe) (chain)
 246
 247 /* Define other aspects of the stack frame.  */
 248
 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;}
 254
 255 /* Saved Pc.  */
 256
 257 #define FRAME_SAVED_PC(FRAME) (read_memory_integer ((FRAME)->frame + 16, 4))
 258
 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) \
 269  (((fi)->next_frame                                  \
 270    ? read_memory_integer ((fi)->next_frame + 8, 4)   \
 271    : /* read_register (AP_REGNUM) */ 0))
 272
 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) \
 277  (((fi)->next_frame                                  \
 278    ? read_memory_integer ((fi)->next_frame + 8, 4)   \
 279    : read_register (AP_REGNUM) /* 0 */))
 280
 281 #define FRAME_LOCALS_ADDRESS(fi) ((fi)->frame)
 282
 283 /* Return number of args passed to a frame.
 284    Can return -1, meaning no way to tell.  */
 285
 286 #define FRAME_NUM_ARGS(numargs, fi)  \
 287 { numargs = (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1)); }
 288
 289 /* Return number of bytes at start of arglist that are not really args.  */
 290
 291 #define FRAME_ARGS_SKIP 4
 292
 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.  */
 298
 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;  \
 316 }
 317 \f
 318 /* Things needed for making the inferior call functions.  */
 319
 320 /* Push an empty stack frame, to record the current PC, etc.  */
 321
 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)   \
 332                       + 0x2fff0000);                \
 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)); }
 337
 338 /* Discard from the stack the innermost frame, restoring all registers.  */
 339
 340 #define POP_FRAME  \
 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,                                     \
 345                   (regmask & 0xffff)                             \
 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));   \
 350   fp += 16;                                                      \
 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),\
 361                                         read_pc ())); }
 362
 363 /* This sequence of words is the instructions
 364      calls #69, @#32323232
 365      bpt
 366    Note this is 8 bytes.  */
 367
 368 #define CALL_DUMMY {0x329f69fb, 0x03323232}
 369
 370 #define CALL_DUMMY_START_OFFSET 0  /* Start execution at beginning of dummy */
 371
 372 /* Insert the specified number of args and function address
 373    into a call sequence of the above form stored at DUMMYNAME.  */
 374
 375 #define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p)   \
 376 { *((char *) dummyname + 1) = nargs;            \
 377   *(int *)((char *) dummyname + 3) = fun; }