gdb/tm-vax.h

   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    However, if FRAME_CHAIN_VALID returns zero,
 224    it means the given frame is the outermost one and has no caller.  */
 225
 226 /* In the case of the Vax, the frame's nominal address is the FP value,
 227    and 12 bytes later comes the saved previous FP value as a 4-byte word.  */
 228
 229 #define FRAME_CHAIN(thisframe)  \
 230   (outside_startup_file ((thisframe)->pc) ? \
 231    read_memory_integer ((thisframe)->frame + 12, 4) :\
 232    0)
 233
 234 #define FRAME_CHAIN_VALID(chain, thisframe) \
 235   (chain != 0 && (outside_startup_file (FRAME_SAVED_PC (thisframe))))
 236
 237 /* Define other aspects of the stack frame.  */
 238
 239 /* A macro that tells us whether the function invocation represented
 240    by FI does not have a frame on the stack associated with it.  If it
 241    does not, FRAMELESS is set to 1, else 0.  */
 242 /* On the vax, all functions have frames.  */
 243 #define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS)  {(FRAMELESS) = 0;}
 244
 245 /* Saved Pc.  */
 246
 247 #define FRAME_SAVED_PC(FRAME) (read_memory_integer ((FRAME)->frame + 16, 4))
 248
 249 /* Cannot find the AP register value directly from the FP value.  Must
 250    find it saved in the frame called by this one, or in the AP
 251    register for the innermost frame.  However, there is no way to tell
 252    the difference between the innermost frame and a frame for which we
 253    just don't know the frame that it called (e.g. "info frame
 254    0x7ffec789").  For the sake of argument suppose that the stack is
 255    somewhat trashed (which is one reason that "info frame" exists).
 256    So return 0 (indicating we don't know the address of
 257    the arglist) if we don't know what frame this frame calls.  */
 258 #define FRAME_ARGS_ADDRESS_CORRECT(fi) \
 259  (((fi)->next_frame                                  \
 260    ? read_memory_integer ((fi)->next_frame + 8, 4)   \
 261    : /* read_register (AP_REGNUM) */ 0))
 262
 263 /* In most of GDB, getting the args address is too important to
 264    just say "I don't know".  This is sometimes wrong for functions
 265    that aren't on top of the stack, but c'est la vie.  */
 266 #define FRAME_ARGS_ADDRESS(fi) \
 267  (((fi)->next_frame                                  \
 268    ? read_memory_integer ((fi)->next_frame + 8, 4)   \
 269    : read_register (AP_REGNUM) /* 0 */))
 270
 271 #define FRAME_LOCALS_ADDRESS(fi) ((fi)->frame)
 272
 273 /* Return number of args passed to a frame.
 274    Can return -1, meaning no way to tell.  */
 275
 276 #define FRAME_NUM_ARGS(numargs, fi)  \
 277 { numargs = (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1)); }
 278
 279 /* Return number of bytes at start of arglist that are not really args.  */
 280
 281 #define FRAME_ARGS_SKIP 4
 282
 283 /* Put here the code to store, into a struct frame_saved_regs,
 284    the addresses of the saved registers of frame described by FRAME_INFO.
 285    This includes special registers such as pc and fp saved in special
 286    ways in the stack frame.  sp is even more special:
 287    the address we return for it IS the sp for the next frame.  */
 288
 289 #define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs) \
 290 { register int regnum;     \
 291   register int regmask = read_memory_integer ((frame_info)->frame+4, 4) >> 16; \
 292   register CORE_ADDR next_addr;     \
 293   bzero (&frame_saved_regs, sizeof frame_saved_regs);     \
 294   next_addr = (frame_info)->frame + 16;     \
 295   /* Regmask's low bit is for register 0,     \
 296      which is the first one that would be pushed.  */     \
 297   for (regnum = 0; regnum < 12; regnum++, regmask >>= 1)  \
 298     (frame_saved_regs).regs[regnum] = (regmask & 1) ? (next_addr += 4) : 0;  \
 299   (frame_saved_regs).regs[SP_REGNUM] = next_addr + 4;  \
 300   if (read_memory_integer ((frame_info)->frame + 4, 4) & 0x20000000)   \
 301     (frame_saved_regs).regs[SP_REGNUM] += 4 + 4 * read_memory_integer (next_addr + 4, 4);  \
 302   (frame_saved_regs).regs[PC_REGNUM] = (frame_info)->frame + 16;  \
 303   (frame_saved_regs).regs[FP_REGNUM] = (frame_info)->frame + 12;  \
 304   (frame_saved_regs).regs[AP_REGNUM] = (frame_info)->frame + 8;  \
 305   (frame_saved_regs).regs[PS_REGNUM] = (frame_info)->frame + 4;  \
 306 }
 307 \f
 308 /* Things needed for making the inferior call functions.  */
 309
 310 /* Push an empty stack frame, to record the current PC, etc.  */
 311
 312 #define PUSH_DUMMY_FRAME \
 313 { register CORE_ADDR sp = read_register (SP_REGNUM);\
 314   register int regnum;                              \
 315   sp = push_word (sp, 0); /* arglist */             \
 316   for (regnum = 11; regnum >= 0; regnum--)          \
 317     sp = push_word (sp, read_register (regnum));    \
 318   sp = push_word (sp, read_register (PC_REGNUM));   \
 319   sp = push_word (sp, read_register (FP_REGNUM));   \
 320   sp = push_word (sp, read_register (AP_REGNUM));   \
 321   sp = push_word (sp, (read_register (PS_REGNUM) & 0xffef)   \
 322                       + 0x2fff0000);                \
 323   sp = push_word (sp, 0);                           \
 324   write_register (SP_REGNUM, sp);                   \
 325   write_register (FP_REGNUM, sp);                   \
 326   write_register (AP_REGNUM, sp + 17 * sizeof (int)); }
 327
 328 /* Discard from the stack the innermost frame, restoring all registers.  */
 329
 330 #define POP_FRAME  \
 331 { register CORE_ADDR fp = read_register (FP_REGNUM);             \
 332   register int regnum;                                           \
 333   register int regmask = read_memory_integer (fp + 4, 4);        \
 334   write_register (PS_REGNUM,                                     \
 335                   (regmask & 0xffff)                             \
 336                   | (read_register (PS_REGNUM) & 0xffff0000));   \
 337   write_register (PC_REGNUM, read_memory_integer (fp + 16, 4));  \
 338   write_register (FP_REGNUM, read_memory_integer (fp + 12, 4));  \
 339   write_register (AP_REGNUM, read_memory_integer (fp + 8, 4));   \
 340   fp += 16;                                                      \
 341   for (regnum = 0; regnum < 12; regnum++)                        \
 342     if (regmask & (0x10000 << regnum))                           \
 343       write_register (regnum, read_memory_integer (fp += 4, 4)); \
 344   fp = fp + 4 + ((regmask >> 30) & 3);                           \
 345   if (regmask & 0x20000000)                                      \
 346     { regnum = read_memory_integer (fp, 4);                      \
 347       fp += (regnum + 1) * 4; }                                  \
 348   write_register (SP_REGNUM, fp);                                \
 349   flush_cached_frames ();                                        \
 350   set_current_frame (create_new_frame (read_register (FP_REGNUM),\
 351                                         read_pc ())); }
 352
 353 /* This sequence of words is the instructions
 354      calls #69, @#32323232
 355      bpt
 356    Note this is 8 bytes.  */
 357
 358 #define CALL_DUMMY {0x329f69fb, 0x03323232}
 359
 360 #define CALL_DUMMY_START_OFFSET 0  /* Start execution at beginning of dummy */
 361
 362 /* Insert the specified number of args and function address
 363    into a call sequence of the above form stored at DUMMYNAME.  */
 364
 365 #define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p)   \
 366 { *((char *) dummyname + 1) = nargs;            \
 367   *(int *)((char *) dummyname + 3) = fun; }