gdb/tm-68k.h

   1 /* Parameters for execution on a 68000 series machine.
   2    Copyright (C) 1986, 1987, 1989, 1990 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 /* Generic 68000 stuff, to be included by other m-*.h files.
  21    Define HAVE_68881 if that is the case.  */
  22
  23 #if defined (HAVE_68881)
  24 #define IEEE_FLOAT 1
  25 #endif
  26
  27 /* Define the bit, byte, and word ordering of the machine.  */
  28 #define TARGET_BYTE_ORDER BIG_ENDIAN
  29
  30 /* Offset from address of function to start of its code.
  31    Zero on most machines.  */
  32
  33 #define FUNCTION_START_OFFSET 0
  34
  35 /* Advance PC across any function entry prologue instructions
  36    to reach some "real" code.  */
  37
  38 #define SKIP_PROLOGUE(pc)   \
  39 { register int op = read_memory_integer (pc, 2);        \
  40   if (op == 0047126)                                    \
  41     pc += 4;   /* Skip link #word */                    \
  42   else if (op == 0044016)                               \
  43     pc += 6;   /* Skip link #long */                    \
  44   /* Not sure why branches are here.  */                \
  45   /* From m-isi.h, m-altos.h */                         \
  46   else if (op == 0060000)                               \
  47     pc += 4;   /* Skip bra #word */                     \
  48   else if (op == 00600377)                              \
  49     pc += 6;   /* skip bra #long */                     \
  50   else if ((op & 0177400) == 0060000)                   \
  51     pc += 2;   /* skip bra #char */                     \
  52 }
  53
  54 /* Immediately after a function call, return the saved pc.
  55    Can't always go through the frames for this because on some machines
  56    the new frame is not set up until the new function executes
  57    some instructions.  */
  58
  59 #define SAVED_PC_AFTER_CALL(frame) \
  60 read_memory_integer (read_register (SP_REGNUM), 4)
  61
  62 /* Stack grows downward.  */
  63
  64 #define INNER_THAN <
  65
  66 /* Sequence of bytes for breakpoint instruction.
  67    This is a TRAP instruction.  The last 4 bits (0xf below) is the
  68    vector.  Systems which don't use 0xf should define BREAKPOINT
  69    themselves before including this file.  */
  70
  71 #if !defined (BREAKPOINT)
  72 #define BREAKPOINT {0x4e, 0x4f}
  73 #endif
  74
  75 /* If your kernel resets the pc after the trap happens you may need to
  76    define this in m-68k.h.  */
  77
  78 #if !defined (DECR_PC_AFTER_BREAK)
  79 #define DECR_PC_AFTER_BREAK 2
  80 #endif
  81
  82 /* Nonzero if instruction at PC is a return instruction.  */
  83 /* Allow any of the return instructions, including a trapv and a return
  84    from interupt.  */
  85
  86 #define ABOUT_TO_RETURN(pc) ((read_memory_integer (pc, 2) & ~0x3) == 0x4e74)
  87
  88 /* Return 1 if P points to an invalid floating point value.  */
  89
  90 #define INVALID_FLOAT(p, len) 0   /* Just a first guess; not checked */
  91
  92 /* Say how long registers are.  */
  93
  94 #define REGISTER_TYPE long
  95
  96 #if defined (HAVE_68881)
  97 #  if defined (GDB_TARGET_IS_SUN3)
  98     /* Sun3 status includes fpflags, which shows whether the FPU has been used
  99        by the process, and whether the FPU was done with an instruction or
 100        was interrupted in the middle of a long instruction.  See
 101        <machine/reg.h>.  */
 102     /*                      a&d, pc,sr, fp, fpstat, fpflags   */
 103 #    define NUM_REGS 31
 104 #    define REGISTER_BYTES (16*4 + 8 + 8*12 + 3*4 + 4)
 105 #  else /* Not sun3.  */
 106 #    define NUM_REGS 29
 107 #    define REGISTER_BYTES (16*4 + 8 + 8*12 + 3*4)
 108 #  endif /* Not sun3.  */
 109 #else /* No 68881.  */
 110 #  define NUM_REGS 18
 111 #  define REGISTER_BYTES (16*4 + 8)
 112 #endif /* No 68881.  */
 113
 114 /* Index within `registers' of the first byte of the space for
 115    register N.  */
 116
 117 #if defined (HAVE_68881)
 118 #define REGISTER_BYTE(N)  \
 119  ((N) >= FPC_REGNUM ? (((N) - FPC_REGNUM) * 4) + 168    \
 120   : (N) >= FP0_REGNUM ? (((N) - FP0_REGNUM) * 12) + 72  \
 121   : (N) * 4)
 122
 123 /* Number of bytes of storage in the actual machine representation
 124    for register N.  On the 68000, all regs are 4 bytes
 125    except the floating point regs which are 12 bytes.  */
 126 /* Note that the unsigned cast here forces the result of the
 127    subtraction to very high positive values if N < FP0_REGNUM */
 128
 129 #define REGISTER_RAW_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 8 ? 12 : 4)
 130
 131 /* Number of bytes of storage in the program's representation
 132    for register N.  On the 68000, all regs are 4 bytes
 133    except the floating point regs which are 8-byte doubles.  */
 134
 135 #define REGISTER_VIRTUAL_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 8 ? 8 : 4)
 136
 137 /* Largest value REGISTER_RAW_SIZE can have.  */
 138
 139 #define MAX_REGISTER_RAW_SIZE 12
 140
 141 /* Largest value REGISTER_VIRTUAL_SIZE can have.  */
 142
 143 #define MAX_REGISTER_VIRTUAL_SIZE 8
 144
 145 /* Nonzero if register N requires conversion
 146    from raw format to virtual format.  */
 147
 148 #define REGISTER_CONVERTIBLE(N) (((unsigned)(N) - FP0_REGNUM) < 8)
 149
 150 /* Put the declaration out here because if it's in the macros, PCC
 151    will complain.  */
 152 extern struct ext_format ext_format_68881 [];
 153
 154 /* Convert data from raw format for register REGNUM
 155    to virtual format for register REGNUM.  */
 156
 157 #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO)     \
 158 { \
 159   if ((REGNUM) >= FP0_REGNUM && (REGNUM) < FPC_REGNUM)  \
 160     ieee_extended_to_double (ext_format_68881, (FROM), (TO));   \
 161   else                                  \
 162     bcopy ((FROM), (TO), 4);    \
 163 }
 164
 165 /* Convert data from virtual format for register REGNUM
 166    to raw format for register REGNUM.  */
 167
 168 #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO) \
 169 { \
 170   if ((REGNUM) >= FP0_REGNUM && (REGNUM) < FPC_REGNUM)  \
 171     double_to_ieee_extended (ext_format_68881, (FROM), (TO));   \
 172   else                                  \
 173     bcopy ((FROM), (TO), 4);    \
 174 }
 175
 176 /* Return the GDB type object for the "standard" data type
 177    of data in register N.  */
 178 /* Note, for registers which contain addresses return
 179    pointer to void, not pointer to char, because we don't
 180    want to attempt to print the string after printing the address.  */
 181 #define REGISTER_VIRTUAL_TYPE(N) \
 182  (((unsigned)(N) - FP0_REGNUM) < 8 ? builtin_type_double :           \
 183   (N) == PC_REGNUM || (N) == FP_REGNUM || (N) == SP_REGNUM ?         \
 184   lookup_pointer_type (builtin_type_void) : builtin_type_int)
 185
 186 #else /* no 68881.  */
 187 /* Index within `registers' of the first byte of the space for
 188    register N.  */
 189
 190 #define REGISTER_BYTE(N)  ((N) * 4)
 191
 192 /* Number of bytes of storage in the actual machine representation
 193    for register N.  On the 68000, all regs are 4 bytes.  */
 194
 195 #define REGISTER_RAW_SIZE(N) 4
 196
 197 /* Number of bytes of storage in the program's representation
 198    for register N.  On the 68000, all regs are 4 bytes.  */
 199
 200 #define REGISTER_VIRTUAL_SIZE(N) 4
 201
 202 /* Largest value REGISTER_RAW_SIZE can have.  */
 203
 204 #define MAX_REGISTER_RAW_SIZE 4
 205
 206 /* Largest value REGISTER_VIRTUAL_SIZE can have.  */
 207
 208 #define MAX_REGISTER_VIRTUAL_SIZE 4
 209
 210 /* Nonzero if register N requires conversion
 211    from raw format to virtual format.  */
 212
 213 #define REGISTER_CONVERTIBLE(N) 0
 214
 215 /* Convert data from raw format for register REGNUM
 216    to virtual format for register REGNUM.  */
 217
 218 #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO)  bcopy ((FROM), (TO), 4);
 219
 220 /* Convert data from virtual format for register REGNUM
 221    to raw format for register REGNUM.  */
 222
 223 #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO)  bcopy ((FROM), (TO), 4);
 224
 225 /* Return the GDB type object for the "standard" data type
 226    of data in register N.  */
 227
 228 #define REGISTER_VIRTUAL_TYPE(N)  builtin_type_int
 229
 230 #endif /* No 68881.  */
 231
 232 /* Initializer for an array of names of registers.
 233    Entries beyond the first NUM_REGS are ignored.  */
 234
 235 #define REGISTER_NAMES  \
 236  {"d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", \
 237   "a0", "a1", "a2", "a3", "a4", "a5", "fp", "sp", \
 238   "ps", "pc",  \
 239   "fp0", "fp1", "fp2", "fp3", "fp4", "fp5", "fp6", "fp7", \
 240   "fpcontrol", "fpstatus", "fpiaddr", "fpcode", "fpflags" }
 241
 242 /* Register numbers of various important registers.
 243    Note that some of these values are "real" register numbers,
 244    and correspond to the general registers of the machine,
 245    and some are "phony" register numbers which are too large
 246    to be actual register numbers as far as the user is concerned
 247    but do serve to get the desired values when passed to read_register.  */
 248
 249 #define A1_REGNUM 9
 250 #define FP_REGNUM 14            /* Contains address of executing stack frame */
 251 #define SP_REGNUM 15            /* Contains address of top of stack */
 252 #define PS_REGNUM 16            /* Contains processor status */
 253 #define PC_REGNUM 17            /* Contains program counter */
 254 #if defined (HAVE_68881)
 255 #define FP0_REGNUM 18           /* Floating point register 0 */
 256 #define FPC_REGNUM 26           /* 68881 control register */
 257 #define FPS_REGNUM 27           /* 68881 status register */
 258 #endif /* 68881.  */
 259
 260 /* Store the address of the place in which to copy the structure the
 261    subroutine will return.  This is called from call_function. */
 262
 263 #define STORE_STRUCT_RETURN(ADDR, SP) \
 264   { write_register (A1_REGNUM, (ADDR)); }
 265
 266 /* Extract from an array REGBUF containing the (raw) register state
 267    a function return value of type TYPE, and copy that, in virtual format,
 268    into VALBUF.  This is assuming that floating point values are returned
 269    as doubles in d0/d1.  */
 270
 271 #if !defined (EXTRACT_RETURN_VALUE)
 272 #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
 273   bcopy (REGBUF, VALBUF, TYPE_LENGTH (TYPE))
 274 #endif
 275
 276 /* Write into appropriate registers a function return value
 277    of type TYPE, given in virtual format.  Assumes floats are passed
 278    in d0/d1.  */
 279
 280 #if !defined (STORE_RETURN_VALUE)
 281 #define STORE_RETURN_VALUE(TYPE,VALBUF) \
 282   write_register_bytes (0, VALBUF, TYPE_LENGTH (TYPE))
 283 #endif
 284
 285 /* Extract from an array REGBUF containing the (raw) register state
 286    the address in which a function should return its structure value,
 287    as a CORE_ADDR (or an expression that can be used as one).  */
 288
 289 #define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF) (*(int *)(REGBUF))
 290 \f
 291 /* Describe the pointer in each stack frame to the previous stack frame
 292    (its caller).  */
 293
 294 /* FRAME_CHAIN takes a frame's nominal address
 295    and produces the frame's chain-pointer.
 296
 297    FRAME_CHAIN_COMBINE takes the chain pointer and the frame's nominal address
 298    and produces the nominal address of the caller frame.
 299
 300    However, if FRAME_CHAIN_VALID returns zero,
 301    it means the given frame is the outermost one and has no caller.
 302    In that case, FRAME_CHAIN_COMBINE is not used.  */
 303
 304 /* In the case of the 68000, the frame's nominal address
 305    is the address of a 4-byte word containing the calling frame's address.  */
 306
 307 #define FRAME_CHAIN(thisframe)  \
 308   (outside_startup_file ((thisframe)->pc) ? \
 309    read_memory_integer ((thisframe)->frame, 4) :\
 310    0)
 311
 312 #define FRAME_CHAIN_VALID(chain, thisframe) \
 313   (chain != 0 && outside_startup_file (FRAME_SAVED_PC (thisframe)))
 314
 315 #define FRAME_CHAIN_COMBINE(chain, thisframe) (chain)
 316
 317 /* Define other aspects of the stack frame.  */
 318
 319 /* A macro that tells us whether the function invocation represented
 320    by FI does not have a frame on the stack associated with it.  If it
 321    does not, FRAMELESS is set to 1, else 0.  */
 322 #define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) \
 323   (FRAMELESS) = frameless_look_for_prologue(FI)
 324
 325 #define FRAME_SAVED_PC(FRAME) (read_memory_integer ((FRAME)->frame + 4, 4))
 326
 327 #define FRAME_ARGS_ADDRESS(fi) ((fi)->frame)
 328
 329 #define FRAME_LOCALS_ADDRESS(fi) ((fi)->frame)
 330
 331 /* Set VAL to the number of args passed to frame described by FI.
 332    Can set VAL to -1, meaning no way to tell.  */
 333
 334 /* We can't tell how many args there are
 335    now that the C compiler delays popping them.  */
 336 #if !defined (FRAME_NUM_ARGS)
 337 #define FRAME_NUM_ARGS(val,fi) (val = -1)
 338 #endif
 339
 340 /* Return number of bytes at start of arglist that are not really args.  */
 341
 342 #define FRAME_ARGS_SKIP 8
 343
 344 /* Put here the code to store, into a struct frame_saved_regs,
 345    the addresses of the saved registers of frame described by FRAME_INFO.
 346    This includes special registers such as pc and fp saved in special
 347    ways in the stack frame.  sp is even more special:
 348    the address we return for it IS the sp for the next frame.  */
 349
 350 #if !defined (FRAME_FIND_SAVED_REGS)
 351 #if defined (HAVE_68881)
 352 #define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs)             \
 353 { register int regnum;                                                  \
 354   register int regmask;                                                 \
 355   register CORE_ADDR next_addr;                                         \
 356   register CORE_ADDR pc;                                                \
 357   int nextinsn;                                                         \
 358   bzero (&frame_saved_regs, sizeof frame_saved_regs);                   \
 359   if ((frame_info)->pc >= (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM*4 - 8*12 - 4 \
 360       && (frame_info)->pc <= (frame_info)->frame)                               \
 361     { next_addr = (frame_info)->frame;                                  \
 362       pc = (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM * 4 - 8*12 - 4; }\
 363   else                                                                  \
 364     { pc = get_pc_function_start ((frame_info)->pc);                    \
 365       /* Verify we have a link a6 instruction next;                     \
 366          if not we lose.  If we win, find the address above the saved   \
 367          regs using the amount of storage from the link instruction.  */\
 368       if (044016 == read_memory_integer (pc, 2))                        \
 369         next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 4), pc+=4; \
 370       else if (047126 == read_memory_integer (pc, 2))                   \
 371         next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 2), pc+=2; \
 372       else goto lose;                                                   \
 373       /* If have an addal #-n, sp next, adjust next_addr.  */           \
 374       if ((0177777 & read_memory_integer (pc, 2)) == 0157774)           \
 375         next_addr += read_memory_integer (pc += 2, 4), pc += 4;         \
 376     }                                                                   \
 377   /* next should be a moveml to (sp) or -(sp) or a movl r,-(sp) */      \
 378   regmask = read_memory_integer (pc + 2, 2);                            \
 379   /* But before that can come an fmovem.  Check for it.  */             \
 380   nextinsn = 0xffff & read_memory_integer (pc, 2);                      \
 381   if (0xf227 == nextinsn                                                \
 382       && (regmask & 0xff00) == 0xe000)                                  \
 383     { pc += 4; /* Regmask's low bit is for register fp7, the first pushed */ \
 384       for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--, regmask >>= 1)              \
 385         if (regmask & 1)                                                \
 386           (frame_saved_regs).regs[regnum] = (next_addr -= 12);          \
 387       regmask = read_memory_integer (pc + 2, 2); }                      \
 388   if (0044327 == read_memory_integer (pc, 2))                           \
 389     { pc += 4; /* Regmask's low bit is for register 0, the first written */ \
 390       for (regnum = 0; regnum < 16; regnum++, regmask >>= 1)            \
 391         if (regmask & 1)                                                \
 392           (frame_saved_regs).regs[regnum] = (next_addr += 4) - 4; }     \
 393   else if (0044347 == read_memory_integer (pc, 2))                      \
 394     { pc += 4; /* Regmask's low bit is for register 15, the first pushed */ \
 395       for (regnum = 15; regnum >= 0; regnum--, regmask >>= 1)           \
 396         if (regmask & 1)                                                \
 397           (frame_saved_regs).regs[regnum] = (next_addr -= 4); }         \
 398   else if (0x2f00 == (0xfff0 & read_memory_integer (pc, 2)))            \
 399     { regnum = 0xf & read_memory_integer (pc, 2); pc += 2;              \
 400       (frame_saved_regs).regs[regnum] = (next_addr -= 4); }             \
 401   /* fmovemx to index of sp may follow.  */                             \
 402   regmask = read_memory_integer (pc + 2, 2);                            \
 403   nextinsn = 0xffff & read_memory_integer (pc, 2);                      \
 404   if (0xf236 == nextinsn                                                \
 405       && (regmask & 0xff00) == 0xf000)                                  \
 406     { pc += 10; /* Regmask's low bit is for register fp0, the first written */ \
 407       for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--, regmask >>= 1)              \
 408         if (regmask & 1)                                                \
 409           (frame_saved_regs).regs[regnum] = (next_addr += 12) - 12;     \
 410       regmask = read_memory_integer (pc + 2, 2); }                      \
 411   /* clrw -(sp); movw ccr,-(sp) may follow.  */                         \
 412   if (0x426742e7 == read_memory_integer (pc, 4))                        \
 413     (frame_saved_regs).regs[PS_REGNUM] = (next_addr -= 4);              \
 414   lose: ;                                                               \
 415   (frame_saved_regs).regs[SP_REGNUM] = (frame_info)->frame + 8;         \
 416   (frame_saved_regs).regs[FP_REGNUM] = (frame_info)->frame;             \
 417   (frame_saved_regs).regs[PC_REGNUM] = (frame_info)->frame + 4;         \
 418 }
 419 #else /* no 68881.  */
 420 #define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs)             \
 421 { register int regnum;                                                  \
 422   register int regmask;                                                 \
 423   register CORE_ADDR next_addr;                                         \
 424   register CORE_ADDR pc;                                                \
 425   bzero (&frame_saved_regs, sizeof frame_saved_regs);                   \
 426   if ((frame_info)->pc >= (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM*4 - 4 \
 427       && (frame_info)->pc <= (frame_info)->frame)                               \
 428     { next_addr = (frame_info)->frame;                                  \
 429       pc = (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM * 4 - 4; }\
 430   else                                                                  \
 431     { pc = get_pc_function_start ((frame_info)->pc);                    \
 432       /* Verify we have a link a6 instruction next;                     \
 433          if not we lose.  If we win, find the address above the saved   \
 434          regs using the amount of storage from the link instruction.  */\
 435       if (044016 == read_memory_integer (pc, 2))                        \
 436         next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 4), pc+=4; \
 437       else if (047126 == read_memory_integer (pc, 2))                   \
 438         next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 2), pc+=2; \
 439       else goto lose;                                                   \
 440       /* If have an addal #-n, sp next, adjust next_addr.  */           \
 441       if ((0177777 & read_memory_integer (pc, 2)) == 0157774)           \
 442         next_addr += read_memory_integer (pc += 2, 4), pc += 4;         \
 443     }                                                                   \
 444   /* next should be a moveml to (sp) or -(sp) or a movl r,-(sp) */      \
 445   regmask = read_memory_integer (pc + 2, 2);                            \
 446   if (0044327 == read_memory_integer (pc, 2))                           \
 447     { pc += 4; /* Regmask's low bit is for register 0, the first written */ \
 448       for (regnum = 0; regnum < 16; regnum++, regmask >>= 1)            \
 449         if (regmask & 1)                                                \
 450           (frame_saved_regs).regs[regnum] = (next_addr += 4) - 4; }     \
 451   else if (0044347 == read_memory_integer (pc, 2))                      \
 452     { pc += 4; /* Regmask's low bit is for register 15, the first pushed */ \
 453       for (regnum = 15; regnum >= 0; regnum--, regmask >>= 1)           \
 454         if (regmask & 1)                                                \
 455           (frame_saved_regs).regs[regnum] = (next_addr -= 4); }         \
 456   else if (0x2f00 == 0xfff0 & read_memory_integer (pc, 2))              \
 457     { regnum = 0xf & read_memory_integer (pc, 2); pc += 2;              \
 458       (frame_saved_regs).regs[regnum] = (next_addr -= 4); }             \
 459   /* clrw -(sp); movw ccr,-(sp) may follow.  */                         \
 460   if (0x426742e7 == read_memory_integer (pc, 4))                        \
 461     (frame_saved_regs).regs[PS_REGNUM] = (next_addr -= 4);              \
 462   lose: ;                                                               \
 463   (frame_saved_regs).regs[SP_REGNUM] = (frame_info)->frame + 8;         \
 464   (frame_saved_regs).regs[FP_REGNUM] = (frame_info)->frame;             \
 465   (frame_saved_regs).regs[PC_REGNUM] = (frame_info)->frame + 4;         \
 466 }
 467 #endif /* no 68881.  */
 468 #endif /* no FIND_FRAME_SAVED_REGS.  */
 469
 470 /* Note that stuff for calling inferior functions is not in this file
 471    because the call dummy is different for different breakpoint
 472    instructions, which are different on different systems.  Perhaps
 473    they could be merged, but I haven't bothered.  */