gdb/tm-vax.h

   1 /* Definitions to make GDB run on a vax under 4.2bsd.
   2    Copyright 1986, 1987, 1989, 1991, 1993 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 /* Offset from address of function to start of its code.
  44    Zero on most machines.  */
  45
  46 #define FUNCTION_START_OFFSET 2
  47
  48 /* Advance PC across any function entry prologue instructions
  49    to reach some "real" code.  */
  50
  51 #define SKIP_PROLOGUE(pc)       \
  52 { register int op = (unsigned char) read_memory_integer (pc, 1);  \
  53   if (op == 0x11) pc += 2;  /* skip brb */                        \
  54   if (op == 0x31) pc += 3;  /* skip brw */                        \
  55   if (op == 0xC2 &&                                               \
  56       ((unsigned char) read_memory_integer (pc+2, 1)) == 0x5E)    \
  57     pc += 3;  /* skip subl2 */                                    \
  58   if (op == 0x9E &&                                               \
  59       ((unsigned char) read_memory_integer (pc+1, 1)) == 0xAE &&  \
  60       ((unsigned char) read_memory_integer(pc+3, 1)) == 0x5E)     \
  61      pc += 4;  /* skip movab */                                   \
  62   if (op == 0x9E &&                                               \
  63       ((unsigned char) read_memory_integer (pc+1, 1)) == 0xCE &&  \
  64       ((unsigned char) read_memory_integer(pc+4, 1)) == 0x5E)     \
  65     pc += 5;  /* skip movab */                                    \
  66   if (op == 0x9E &&                                               \
  67       ((unsigned char) read_memory_integer (pc+1, 1)) == 0xEE &&  \
  68       ((unsigned char) read_memory_integer(pc+6, 1)) == 0x5E)     \
  69     pc += 7;  /* skip movab */                                    \
  70 }
  71
  72 /* Immediately after a function call, return the saved pc.
  73    Can't always go through the frames for this because on some machines
  74    the new frame is not set up until the new function executes
  75    some instructions.  */
  76
  77 #define SAVED_PC_AFTER_CALL(frame) FRAME_SAVED_PC(frame)
  78
  79 #define TARGET_UPAGES 10
  80 #define TARGET_NBPG 512
  81 #define STACK_END_ADDR (0x80000000 - (TARGET_UPAGES * TARGET_NBPG))
  82
  83 /* On the VAX, sigtramp is in the u area.  Can't check the exact
  84    addresses because for cross-debugging we don't have VAX include
  85    files around.  This should be close enough.  */
  86 #define IN_SIGTRAMP(pc, name) ((pc) >= STACK_END_ADDR && (pc < 0x80000000))
  87
  88 /* Stack grows downward.  */
  89
  90 #define INNER_THAN <
  91
  92 /* Sequence of bytes for breakpoint instruction.  */
  93
  94 #define BREAKPOINT {3}
  95
  96 /* Amount PC must be decremented by after a breakpoint.
  97    This is often the number of bytes in BREAKPOINT
  98    but not always.  */
  99
 100 #define DECR_PC_AFTER_BREAK 0
 101
 102 /* Nonzero if instruction at PC is a return instruction.  */
 103
 104 #define ABOUT_TO_RETURN(pc) (read_memory_integer (pc, 1) == 04)
 105
 106 /* Return 1 if P points to an invalid floating point value.
 107    LEN is the length in bytes -- not relevant on the Vax.  */
 108
 109 #define INVALID_FLOAT(p, len) ((*(short *) p & 0xff80) == 0x8000)
 110
 111 /* Say how long (ordinary) registers are.  */
 112
 113 #define REGISTER_TYPE long
 114
 115 /* Number of machine registers */
 116
 117 #define NUM_REGS 17
 118
 119 /* Initializer for an array of names of registers.
 120    There should be NUM_REGS strings in this initializer.  */
 121
 122 #define REGISTER_NAMES {"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc", "ps"}
 123
 124 /* Register numbers of various important registers.
 125    Note that some of these values are "real" register numbers,
 126    and correspond to the general registers of the machine,
 127    and some are "phony" register numbers which are too large
 128    to be actual register numbers as far as the user is concerned
 129    but do serve to get the desired values when passed to read_register.  */
 130
 131 #define AP_REGNUM 12
 132 #define FP_REGNUM 13            /* Contains address of executing stack frame */
 133 #define SP_REGNUM 14            /* Contains address of top of stack */
 134 #define PC_REGNUM 15            /* Contains program counter */
 135 #define PS_REGNUM 16            /* Contains processor status */
 136
 137 /* Total amount of space needed to store our copies of the machine's
 138    register state, the array `registers'.  */
 139 #define REGISTER_BYTES (17*4)
 140
 141 /* Index within `registers' of the first byte of the space for
 142    register N.  */
 143
 144 #define REGISTER_BYTE(N) ((N) * 4)
 145
 146 /* Number of bytes of storage in the actual machine representation
 147    for register N.  On the vax, all regs are 4 bytes.  */
 148
 149 #define REGISTER_RAW_SIZE(N) 4
 150
 151 /* Number of bytes of storage in the program's representation
 152    for register N.  On the vax, all regs are 4 bytes.  */
 153
 154 #define REGISTER_VIRTUAL_SIZE(N) 4
 155
 156 /* Largest value REGISTER_RAW_SIZE can have.  */
 157
 158 #define MAX_REGISTER_RAW_SIZE 4
 159
 160 /* Largest value REGISTER_VIRTUAL_SIZE can have.  */
 161
 162 #define MAX_REGISTER_VIRTUAL_SIZE 4
 163
 164 /* Nonzero if register N requires conversion
 165    from raw format to virtual format.  */
 166
 167 #define REGISTER_CONVERTIBLE(N) 0
 168
 169 /* Convert data from raw format for register REGNUM
 170    to virtual format for register REGNUM.  */
 171
 172 #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO)     \
 173   bcopy ((FROM), (TO), 4);
 174
 175 /* Convert data from virtual format for register REGNUM
 176    to raw format for register REGNUM.  */
 177
 178 #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO) \
 179   bcopy ((FROM), (TO), 4);
 180
 181 /* Return the GDB type object for the "standard" data type
 182    of data in register N.  */
 183
 184 #define REGISTER_VIRTUAL_TYPE(N) builtin_type_int
 185
 186 /* Store the address of the place in which to copy the structure the
 187    subroutine will return.  This is called from call_function. */
 188
 189 #define STORE_STRUCT_RETURN(ADDR, SP) \
 190   { write_register (1, (ADDR)); }
 191
 192 /* Extract from an array REGBUF containing the (raw) register state
 193    a function return value of type TYPE, and copy that, in virtual format,
 194    into VALBUF.  */
 195
 196 #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
 197   bcopy (REGBUF, VALBUF, TYPE_LENGTH (TYPE))
 198
 199 /* Write into appropriate registers a function return value
 200    of type TYPE, given in virtual format.  */
 201
 202 #define STORE_RETURN_VALUE(TYPE,VALBUF) \
 203   write_register_bytes (0, VALBUF, TYPE_LENGTH (TYPE))
 204
 205 /* Extract from an array REGBUF containing the (raw) register state
 206    the address in which a function should return its structure value,
 207    as a CORE_ADDR (or an expression that can be used as one).  */
 208
 209 #define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF) (*(int *)(REGBUF))
 210
 211 \f
 212 /* Describe the pointer in each stack frame to the previous stack frame
 213    (its caller).  */
 214
 215 /* FRAME_CHAIN takes a frame's nominal address
 216    and produces the frame's chain-pointer. */
 217
 218 /* In the case of the Vax, the frame's nominal address is the FP value,
 219    and 12 bytes later comes the saved previous FP value as a 4-byte word.  */
 220
 221 #define FRAME_CHAIN(thisframe)  \
 222   (!inside_entry_file ((thisframe)->pc) ? \
 223    read_memory_integer ((thisframe)->frame + 12, 4) :\
 224    0)
 225
 226 /* Define other aspects of the stack frame.  */
 227
 228 /* A macro that tells us whether the function invocation represented
 229    by FI does not have a frame on the stack associated with it.  If it
 230    does not, FRAMELESS is set to 1, else 0.  */
 231 /* On the vax, all functions have frames.  */
 232 #define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS)  {(FRAMELESS) = 0;}
 233
 234 /* Saved Pc.  */
 235
 236 #define FRAME_SAVED_PC(FRAME) (read_memory_integer ((FRAME)->frame + 16, 4))
 237
 238 /* Cannot find the AP register value directly from the FP value.  Must
 239    find it saved in the frame called by this one, or in the AP
 240    register for the innermost frame.  However, there is no way to tell
 241    the difference between the innermost frame and a frame for which we
 242    just don't know the frame that it called (e.g. "info frame
 243    0x7ffec789").  For the sake of argument suppose that the stack is
 244    somewhat trashed (which is one reason that "info frame" exists).
 245    So return 0 (indicating we don't know the address of
 246    the arglist) if we don't know what frame this frame calls.  */
 247 #define FRAME_ARGS_ADDRESS_CORRECT(fi) \
 248  (((fi)->next_frame                                  \
 249    ? read_memory_integer ((fi)->next_frame + 8, 4)   \
 250    : /* read_register (AP_REGNUM) */ 0))
 251
 252 /* In most of GDB, getting the args address is too important to
 253    just say "I don't know".  This is sometimes wrong for functions
 254    that aren't on top of the stack, but c'est la vie.  */
 255 #define FRAME_ARGS_ADDRESS(fi) \
 256  (((fi)->next_frame                                  \
 257    ? read_memory_integer ((fi)->next_frame + 8, 4)   \
 258    : read_register (AP_REGNUM) /* 0 */))
 259
 260 #define FRAME_LOCALS_ADDRESS(fi) ((fi)->frame)
 261
 262 /* Return number of args passed to a frame.
 263    Can return -1, meaning no way to tell.  */
 264
 265 #define FRAME_NUM_ARGS(numargs, fi)  \
 266 { numargs = (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1)); }
 267
 268 /* Return number of bytes at start of arglist that are not really args.  */
 269
 270 #define FRAME_ARGS_SKIP 4
 271
 272 /* Put here the code to store, into a struct frame_saved_regs,
 273    the addresses of the saved registers of frame described by FRAME_INFO.
 274    This includes special registers such as pc and fp saved in special
 275    ways in the stack frame.  sp is even more special:
 276    the address we return for it IS the sp for the next frame.  */
 277
 278 #define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs) \
 279 { register int regnum;     \
 280   register int regmask = read_memory_integer ((frame_info)->frame+4, 4) >> 16; \
 281   register CORE_ADDR next_addr;     \
 282   bzero (&frame_saved_regs, sizeof frame_saved_regs);     \
 283   next_addr = (frame_info)->frame + 16;     \
 284   /* Regmask's low bit is for register 0,     \
 285      which is the first one that would be pushed.  */     \
 286   for (regnum = 0; regnum < 12; regnum++, regmask >>= 1)  \
 287     (frame_saved_regs).regs[regnum] = (regmask & 1) ? (next_addr += 4) : 0;  \
 288   (frame_saved_regs).regs[SP_REGNUM] = next_addr + 4;  \
 289   if (read_memory_integer ((frame_info)->frame + 4, 4) & 0x20000000)   \
 290     (frame_saved_regs).regs[SP_REGNUM] += 4 + 4 * read_memory_integer (next_addr + 4, 4);  \
 291   (frame_saved_regs).regs[PC_REGNUM] = (frame_info)->frame + 16;  \
 292   (frame_saved_regs).regs[FP_REGNUM] = (frame_info)->frame + 12;  \
 293   (frame_saved_regs).regs[AP_REGNUM] = (frame_info)->frame + 8;  \
 294   (frame_saved_regs).regs[PS_REGNUM] = (frame_info)->frame + 4;  \
 295 }
 296 \f
 297 /* Things needed for making the inferior call functions.  */
 298
 299 /* Push an empty stack frame, to record the current PC, etc.  */
 300
 301 #define PUSH_DUMMY_FRAME \
 302 { register CORE_ADDR sp = read_register (SP_REGNUM);\
 303   register int regnum;                              \
 304   sp = push_word (sp, 0); /* arglist */             \
 305   for (regnum = 11; regnum >= 0; regnum--)          \
 306     sp = push_word (sp, read_register (regnum));    \
 307   sp = push_word (sp, read_register (PC_REGNUM));   \
 308   sp = push_word (sp, read_register (FP_REGNUM));   \
 309   sp = push_word (sp, read_register (AP_REGNUM));   \
 310   sp = push_word (sp, (read_register (PS_REGNUM) & 0xffef)   \
 311                       + 0x2fff0000);                \
 312   sp = push_word (sp, 0);                           \
 313   write_register (SP_REGNUM, sp);                   \
 314   write_register (FP_REGNUM, sp);                   \
 315   write_register (AP_REGNUM, sp + 17 * sizeof (int)); }
 316
 317 /* Discard from the stack the innermost frame, restoring all registers.  */
 318
 319 #define POP_FRAME  \
 320 { register CORE_ADDR fp = read_register (FP_REGNUM);             \
 321   register int regnum;                                           \
 322   register int regmask = read_memory_integer (fp + 4, 4);        \
 323   write_register (PS_REGNUM,                                     \
 324                   (regmask & 0xffff)                             \
 325                   | (read_register (PS_REGNUM) & 0xffff0000));   \
 326   write_register (PC_REGNUM, read_memory_integer (fp + 16, 4));  \
 327   write_register (FP_REGNUM, read_memory_integer (fp + 12, 4));  \
 328   write_register (AP_REGNUM, read_memory_integer (fp + 8, 4));   \
 329   fp += 16;                                                      \
 330   for (regnum = 0; regnum < 12; regnum++)                        \
 331     if (regmask & (0x10000 << regnum))                           \
 332       write_register (regnum, read_memory_integer (fp += 4, 4)); \
 333   fp = fp + 4 + ((regmask >> 30) & 3);                           \
 334   if (regmask & 0x20000000)                                      \
 335     { regnum = read_memory_integer (fp, 4);                      \
 336       fp += (regnum + 1) * 4; }                                  \
 337   write_register (SP_REGNUM, fp);                                \
 338   flush_cached_frames ();                                        \
 339   set_current_frame (create_new_frame (read_register (FP_REGNUM),\
 340                                         read_pc ())); }
 341
 342 /* This sequence of words is the instructions
 343      calls #69, @#32323232
 344      bpt
 345    Note this is 8 bytes.  */
 346
 347 #define CALL_DUMMY {0x329f69fb, 0x03323232}
 348
 349 #define CALL_DUMMY_START_OFFSET 0  /* Start execution at beginning of dummy */
 350
 351 /* Insert the specified number of args and function address
 352    into a call sequence of the above form stored at DUMMYNAME.  */
 353
 354 #define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p)   \
 355 { *((char *) dummyname + 1) = nargs;            \
 356   *(int *)((char *) dummyname + 3) = fun; }