gdb/config/vax/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
  21 #define TARGET_BYTE_ORDER LITTLE_ENDIAN
  22
  23 /* Offset from address of function to start of its code.
  24    Zero on most machines.  */
  25
  26 #define FUNCTION_START_OFFSET 2
  27
  28 /* Advance PC across any function entry prologue instructions
  29    to reach some "real" code.  */
  30
  31 #define SKIP_PROLOGUE(pc)       \
  32 { register int op = (unsigned char) read_memory_integer (pc, 1);  \
  33   if (op == 0x11) pc += 2;  /* skip brb */                        \
  34   if (op == 0x31) pc += 3;  /* skip brw */                        \
  35   if (op == 0xC2 &&                                               \
  36       ((unsigned char) read_memory_integer (pc+2, 1)) == 0x5E)    \
  37     pc += 3;  /* skip subl2 */                                    \
  38   if (op == 0x9E &&                                               \
  39       ((unsigned char) read_memory_integer (pc+1, 1)) == 0xAE &&  \
  40       ((unsigned char) read_memory_integer(pc+3, 1)) == 0x5E)     \
  41      pc += 4;  /* skip movab */                                   \
  42   if (op == 0x9E &&                                               \
  43       ((unsigned char) read_memory_integer (pc+1, 1)) == 0xCE &&  \
  44       ((unsigned char) read_memory_integer(pc+4, 1)) == 0x5E)     \
  45     pc += 5;  /* skip movab */                                    \
  46   if (op == 0x9E &&                                               \
  47       ((unsigned char) read_memory_integer (pc+1, 1)) == 0xEE &&  \
  48       ((unsigned char) read_memory_integer(pc+6, 1)) == 0x5E)     \
  49     pc += 7;  /* skip movab */                                    \
  50 }
  51
  52 /* Immediately after a function call, return the saved pc.
  53    Can't always go through the frames for this because on some machines
  54    the new frame is not set up until the new function executes
  55    some instructions.  */
  56
  57 #define SAVED_PC_AFTER_CALL(frame) FRAME_SAVED_PC(frame)
  58
  59 #define TARGET_UPAGES 14
  60 #define TARGET_NBPG 512
  61 #define STACK_END_ADDR (0x80000000 - (TARGET_UPAGES * TARGET_NBPG))
  62
  63 /* On the VAX, sigtramp is in the u area.  Can't check the exact
  64    addresses because for cross-debugging we don't have VAX include
  65    files around.  This should be close enough.  */
  66 #define SIGTRAMP_START  STACK_END_ADDR
  67 #define SIGTRAMP_END    0x80000000
  68
  69 /* Stack grows downward.  */
  70
  71 #define INNER_THAN <
  72
  73 /* Sequence of bytes for breakpoint instruction.  */
  74
  75 #define BREAKPOINT {3}
  76
  77 /* Amount PC must be decremented by after a breakpoint.
  78    This is often the number of bytes in BREAKPOINT
  79    but not always.  */
  80
  81 #define DECR_PC_AFTER_BREAK 0
  82
  83 /* Nonzero if instruction at PC is a return instruction.  */
  84
  85 #define ABOUT_TO_RETURN(pc) (read_memory_integer (pc, 1) == 04)
  86
  87 /* Return 1 if P points to an invalid floating point value.
  88    LEN is the length in bytes -- not relevant on the Vax.  */
  89
  90 #define INVALID_FLOAT(p, len) ((*(short *) p & 0xff80) == 0x8000)
  91
  92 /* Say how long (ordinary) registers are.  */
  93
  94 #define REGISTER_TYPE long
  95
  96 /* Number of machine registers */
  97
  98 #define NUM_REGS 17
  99
 100 /* Initializer for an array of names of registers.
 101    There should be NUM_REGS strings in this initializer.  */
 102
 103 #define REGISTER_NAMES {"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc", "ps"}
 104
 105 /* Register numbers of various important registers.
 106    Note that some of these values are "real" register numbers,
 107    and correspond to the general registers of the machine,
 108    and some are "phony" register numbers which are too large
 109    to be actual register numbers as far as the user is concerned
 110    but do serve to get the desired values when passed to read_register.  */
 111
 112 #define AP_REGNUM 12
 113 #define FP_REGNUM 13            /* Contains address of executing stack frame */
 114 #define SP_REGNUM 14            /* Contains address of top of stack */
 115 #define PC_REGNUM 15            /* Contains program counter */
 116 #define PS_REGNUM 16            /* Contains processor status */
 117
 118 /* Total amount of space needed to store our copies of the machine's
 119    register state, the array `registers'.  */
 120 #define REGISTER_BYTES (17*4)
 121
 122 /* Index within `registers' of the first byte of the space for
 123    register N.  */
 124
 125 #define REGISTER_BYTE(N) ((N) * 4)
 126
 127 /* Number of bytes of storage in the actual machine representation
 128    for register N.  On the vax, all regs are 4 bytes.  */
 129
 130 #define REGISTER_RAW_SIZE(N) 4
 131
 132 /* Number of bytes of storage in the program's representation
 133    for register N.  On the vax, all regs are 4 bytes.  */
 134
 135 #define REGISTER_VIRTUAL_SIZE(N) 4
 136
 137 /* Largest value REGISTER_RAW_SIZE can have.  */
 138
 139 #define MAX_REGISTER_RAW_SIZE 4
 140
 141 /* Largest value REGISTER_VIRTUAL_SIZE can have.  */
 142
 143 #define MAX_REGISTER_VIRTUAL_SIZE 4
 144
 145 /* Return the GDB type object for the "standard" data type
 146    of data in register N.  */
 147
 148 #define REGISTER_VIRTUAL_TYPE(N) builtin_type_int
 149
 150 /* Store the address of the place in which to copy the structure the
 151    subroutine will return.  This is called from call_function. */
 152
 153 #define STORE_STRUCT_RETURN(ADDR, SP) \
 154   { write_register (1, (ADDR)); }
 155
 156 /* Extract from an array REGBUF containing the (raw) register state
 157    a function return value of type TYPE, and copy that, in virtual format,
 158    into VALBUF.  */
 159
 160 #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
 161   memcpy (VALBUF, REGBUF, TYPE_LENGTH (TYPE))
 162
 163 /* Write into appropriate registers a function return value
 164    of type TYPE, given in virtual format.  */
 165
 166 #define STORE_RETURN_VALUE(TYPE,VALBUF) \
 167   write_register_bytes (0, VALBUF, TYPE_LENGTH (TYPE))
 168
 169 /* Extract from an array REGBUF containing the (raw) register state
 170    the address in which a function should return its structure value,
 171    as a CORE_ADDR (or an expression that can be used as one).  */
 172
 173 #define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF) (*(int *)(REGBUF))
 174
 175 \f
 176 /* Describe the pointer in each stack frame to the previous stack frame
 177    (its caller).  */
 178
 179 /* FRAME_CHAIN takes a frame's nominal address
 180    and produces the frame's chain-pointer. */
 181
 182 /* In the case of the Vax, the frame's nominal address is the FP value,
 183    and 12 bytes later comes the saved previous FP value as a 4-byte word.  */
 184
 185 #define FRAME_CHAIN(thisframe)  \
 186   (!inside_entry_file ((thisframe)->pc) ? \
 187    read_memory_integer ((thisframe)->frame + 12, 4) :\
 188    0)
 189
 190 /* Define other aspects of the stack frame.  */
 191
 192 /* A macro that tells us whether the function invocation represented
 193    by FI does not have a frame on the stack associated with it.  If it
 194    does not, FRAMELESS is set to 1, else 0.  */
 195 /* On the vax, all functions have frames.  */
 196 #define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS)  {(FRAMELESS) = 0;}
 197
 198 /* Saved Pc.  Get it from sigcontext if within sigtramp.  */
 199
 200 /* Offset to saved PC in sigcontext, from <sys/signal.h>.  */
 201 #define SIGCONTEXT_PC_OFFSET 12
 202
 203 #define FRAME_SAVED_PC(FRAME) \
 204   (((FRAME)->signal_handler_caller \
 205     ? sigtramp_saved_pc (FRAME) \
 206     : read_memory_integer ((FRAME)->frame + 16, 4)) \
 207    )
 208
 209 /* Cannot find the AP register value directly from the FP value.  Must
 210    find it saved in the frame called by this one, or in the AP
 211    register for the innermost frame.  However, there is no way to tell
 212    the difference between the innermost frame and a frame for which we
 213    just don't know the frame that it called (e.g. "info frame
 214    0x7ffec789").  For the sake of argument suppose that the stack is
 215    somewhat trashed (which is one reason that "info frame" exists).
 216    So return 0 (indicating we don't know the address of
 217    the arglist) if we don't know what frame this frame calls.  */
 218 #define FRAME_ARGS_ADDRESS_CORRECT(fi) \
 219  (((fi)->next                                  \
 220    ? read_memory_integer ((fi)->next->frame + 8, 4)   \
 221    : /* read_register (AP_REGNUM) */ 0))
 222
 223 /* In most of GDB, getting the args address is too important to
 224    just say "I don't know".  This is sometimes wrong for functions
 225    that aren't on top of the stack, but c'est la vie.  */
 226 #define FRAME_ARGS_ADDRESS(fi) \
 227  (((fi)->next                                  \
 228    ? read_memory_integer ((fi)->next->frame + 8, 4)   \
 229    : read_register (AP_REGNUM) /* 0 */))
 230
 231 #define FRAME_LOCALS_ADDRESS(fi) ((fi)->frame)
 232
 233 /* Return number of args passed to a frame.
 234    Can return -1, meaning no way to tell.  */
 235
 236 #define FRAME_NUM_ARGS(numargs, fi)  \
 237 { numargs = (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1)); }
 238
 239 /* Return number of bytes at start of arglist that are not really args.  */
 240
 241 #define FRAME_ARGS_SKIP 4
 242
 243 /* Put here the code to store, into a struct frame_saved_regs,
 244    the addresses of the saved registers of frame described by FRAME_INFO.
 245    This includes special registers such as pc and fp saved in special
 246    ways in the stack frame.  sp is even more special:
 247    the address we return for it IS the sp for the next frame.  */
 248
 249 #define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs) \
 250 { register int regnum;     \
 251   register int regmask = read_memory_integer ((frame_info)->frame+4, 4) >> 16; \
 252   register CORE_ADDR next_addr;     \
 253   memset (&frame_saved_regs, '\0', sizeof frame_saved_regs);     \
 254   next_addr = (frame_info)->frame + 16;     \
 255   /* Regmask's low bit is for register 0,     \
 256      which is the first one that would be pushed.  */     \
 257   for (regnum = 0; regnum < 12; regnum++, regmask >>= 1)  \
 258     (frame_saved_regs).regs[regnum] = (regmask & 1) ? (next_addr += 4) : 0;  \
 259   (frame_saved_regs).regs[SP_REGNUM] = next_addr + 4;  \
 260   if (read_memory_integer ((frame_info)->frame + 4, 4) & 0x20000000)   \
 261     (frame_saved_regs).regs[SP_REGNUM] += 4 + 4 * read_memory_integer (next_addr + 4, 4);  \
 262   (frame_saved_regs).regs[PC_REGNUM] = (frame_info)->frame + 16;  \
 263   (frame_saved_regs).regs[FP_REGNUM] = (frame_info)->frame + 12;  \
 264   (frame_saved_regs).regs[AP_REGNUM] = (frame_info)->frame + 8;  \
 265   (frame_saved_regs).regs[PS_REGNUM] = (frame_info)->frame + 4;  \
 266 }
 267 \f
 268 /* Things needed for making the inferior call functions.  */
 269
 270 /* Push an empty stack frame, to record the current PC, etc.  */
 271
 272 #define PUSH_DUMMY_FRAME \
 273 { register CORE_ADDR sp = read_register (SP_REGNUM);\
 274   register int regnum;                              \
 275   sp = push_word (sp, 0); /* arglist */             \
 276   for (regnum = 11; regnum >= 0; regnum--)          \
 277     sp = push_word (sp, read_register (regnum));    \
 278   sp = push_word (sp, read_register (PC_REGNUM));   \
 279   sp = push_word (sp, read_register (FP_REGNUM));   \
 280   sp = push_word (sp, read_register (AP_REGNUM));   \
 281   sp = push_word (sp, (read_register (PS_REGNUM) & 0xffef)   \
 282                       + 0x2fff0000);                \
 283   sp = push_word (sp, 0);                           \
 284   write_register (SP_REGNUM, sp);                   \
 285   write_register (FP_REGNUM, sp);                   \
 286   write_register (AP_REGNUM, sp + 17 * sizeof (int)); }
 287
 288 /* Discard from the stack the innermost frame, restoring all registers.  */
 289
 290 #define POP_FRAME  \
 291 { register CORE_ADDR fp = read_register (FP_REGNUM);             \
 292   register int regnum;                                           \
 293   register int regmask = read_memory_integer (fp + 4, 4);        \
 294   write_register (PS_REGNUM,                                     \
 295                   (regmask & 0xffff)                             \
 296                   | (read_register (PS_REGNUM) & 0xffff0000));   \
 297   write_register (PC_REGNUM, read_memory_integer (fp + 16, 4));  \
 298   write_register (FP_REGNUM, read_memory_integer (fp + 12, 4));  \
 299   write_register (AP_REGNUM, read_memory_integer (fp + 8, 4));   \
 300   fp += 16;                                                      \
 301   for (regnum = 0; regnum < 12; regnum++)                        \
 302     if (regmask & (0x10000 << regnum))                           \
 303       write_register (regnum, read_memory_integer (fp += 4, 4)); \
 304   fp = fp + 4 + ((regmask >> 30) & 3);                           \
 305   if (regmask & 0x20000000)                                      \
 306     { regnum = read_memory_integer (fp, 4);                      \
 307       fp += (regnum + 1) * 4; }                                  \
 308   write_register (SP_REGNUM, fp);                                \
 309   flush_cached_frames ();                                        \
 310   set_current_frame (create_new_frame (read_register (FP_REGNUM),\
 311                                         read_pc ())); }
 312
 313 /* This sequence of words is the instructions
 314      calls #69, @#32323232
 315      bpt
 316    Note this is 8 bytes.  */
 317
 318 #define CALL_DUMMY {0x329f69fb, 0x03323232}
 319
 320 #define CALL_DUMMY_START_OFFSET 0  /* Start execution at beginning of dummy */
 321
 322 /* Insert the specified number of args and function address
 323    into a call sequence of the above form stored at DUMMYNAME.  */
 324
 325 #define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p)   \
 326 { *((char *) dummyname + 1) = nargs;            \
 327   *(int *)((char *) dummyname + 3) = fun; }
 328
 329 /* If vax pcc says CHAR or SHORT, it provides the correct address.  */
 330
 331 #define BELIEVE_PCC_PROMOTION 1