gdb/tm-m88k.h

   1 /* Target machine description for generic Motorola 88000, for GDB.
   2    Copyright 1986, 1987, 1988, 1989, 1990, 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 /* g++ support is not yet included.  */
  21
  22 #define TARGET_BYTE_ORDER BIG_ENDIAN
  23
  24 /* We cache information about saved registers in the frame structure,
  25    to save us from having to re-scan function prologues every time
  26    a register in a non-current frame is accessed.  */
  27
  28 #define EXTRA_FRAME_INFO        \
  29         struct frame_saved_regs *fsr;   \
  30         CORE_ADDR locals_pointer;       \
  31         CORE_ADDR args_pointer;
  32
  33 /* Zero the frame_saved_regs pointer when the frame is initialized,
  34    so that FRAME_FIND_SAVED_REGS () will know to allocate and
  35    initialize a frame_saved_regs struct the first time it is called.
  36    Set the arg_pointer to -1, which is not valid; 0 and other values
  37    indicate real, cached values.  */
  38
  39 #define INIT_EXTRA_FRAME_INFO(fromleaf, fi) \
  40         init_extra_frame_info (fromleaf, fi)
  41 extern void init_extra_frame_info ();
  42
  43 #define IEEE_FLOAT
  44
  45 /* Define this if the C compiler puts an underscore at the front
  46    of external names before giving them to the linker.  */
  47
  48 #define NAMES_HAVE_UNDERSCORE
  49
  50 /* Offset from address of function to start of its code.
  51    Zero on most machines.  */
  52
  53 #define FUNCTION_START_OFFSET 0
  54
  55 /* Advance PC across any function entry prologue instructions
  56    to reach some "real" code.  */
  57
  58 #define SKIP_PROLOGUE(frompc)   \
  59         skip_prologue (frompc)
  60 extern CORE_ADDR skip_prologue ();
  61
  62 /* The m88k kernel aligns all instructions on 4-byte boundaries.  The
  63    kernel also uses the least significant two bits for its own hocus
  64    pocus.  When gdb receives an address from the kernel, it needs to
  65    preserve those right-most two bits, but gdb also needs to be careful
  66    to realize that those two bits are not really a part of the address
  67    of an instruction.  Shrug.  */
  68
  69 #define ADDR_BITS_REMOVE(addr) ((addr) & ~3)
  70 #define ADDR_BITS_SET(addr) (((addr) | 0x00000002) - 4)
  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) \
  78   (ADDR_BITS_REMOVE (read_register (SRP_REGNUM)))
  79
  80 /* Stack grows downward.  */
  81
  82 #define INNER_THAN <
  83
  84 /* Sequence of bytes for breakpoint instruction.  */
  85
  86 /* instruction 0xF000D1FF is 'tb0 0,r0,511'
  87    If Bit bit 0 of r0 is clear (always true),
  88    initiate exception processing (trap).
  89  */
  90 #define BREAKPOINT {0xF0, 0x00, 0xD1, 0xFF}
  91
  92 /* Amount PC must be decremented by after a breakpoint.
  93    This is often the number of bytes in BREAKPOINT
  94    but not always.  */
  95
  96 #define DECR_PC_AFTER_BREAK 0
  97
  98 /* Nonzero if instruction at PC is a return instruction.  */
  99 /* 'jmp r1' or 'jmp.n r1' is used to return from a subroutine. */
 100
 101 #define ABOUT_TO_RETURN(pc) (read_memory_integer (pc, 2) == 0xF800)
 102
 103 /* Return 1 if P points to an invalid floating point value.
 104    LEN is the length in bytes.  */
 105
 106 #define INVALID_FLOAT(p, len) IEEE_isNAN(p,len)
 107
 108 /* Say how long (ordinary) registers are.  */
 109
 110 #define REGISTER_TYPE long
 111
 112 /* Number of machine registers */
 113
 114 #define NUM_REGS 38
 115
 116 /* Initializer for an array of names of registers.
 117    There should be NUM_REGS strings in this initializer.  */
 118
 119 #define REGISTER_NAMES {\
 120         "r0",\
 121         "r1",\
 122         "r2",\
 123         "r3",\
 124         "r4",\
 125         "r5",\
 126         "r6",\
 127         "r7",\
 128         "r8",\
 129         "r9",\
 130         "r10",\
 131         "r11",\
 132         "r12",\
 133         "r13",\
 134         "r14",\
 135         "r15",\
 136         "r16",\
 137         "r17",\
 138         "r18",\
 139         "r19",\
 140         "r20",\
 141         "r21",\
 142         "r22",\
 143         "r23",\
 144         "r24",\
 145         "r25",\
 146         "r26",\
 147         "r27",\
 148         "r28",\
 149         "r29",\
 150         "r30",\
 151         "r31",\
 152         "psr",\
 153         "fpsr",\
 154         "fpcr",\
 155         "sxip",\
 156         "snip",\
 157         "sfip",\
 158         "vbr",\
 159         "dmt0",\
 160         "dmd0",\
 161         "dma0",\
 162         "dmt1",\
 163         "dmd1",\
 164         "dma1",\
 165         "dmt2",\
 166         "dmd2",\
 167         "dma2",\
 168         "sr0",\
 169         "sr1",\
 170         "sr2",\
 171         "sr3",\
 172         "fpecr",\
 173         "fphs1",\
 174         "fpls1",\
 175         "fphs2",\
 176         "fpls2",\
 177         "fppt",\
 178         "fprh",\
 179         "fprl",\
 180         "fpit",\
 181         "fpsr",\
 182         "fpcr",\
 183         };
 184
 185
 186 /* Register numbers of various important registers.
 187    Note that some of these values are "real" register numbers,
 188    and correspond to the general registers of the machine,
 189    and some are "phony" register numbers which are too large
 190    to be actual register numbers as far as the user is concerned
 191    but do serve to get the desired values when passed to read_register.  */
 192
 193 #define SRP_REGNUM 1            /* Contains subroutine return pointer */
 194 #define RV_REGNUM 2             /* Contains simple return values */
 195 #define SRA_REGNUM 12           /* Contains address of struct return values */
 196 #define FP_REGNUM 31            /* Reg fetched to locate frame when pgm stops */
 197 #define SP_REGNUM 31            /* Contains address of top of stack */
 198 #define SXIP_REGNUM 35          /* Contains Shadow Execute Instruction Pointer */
 199 #define SNIP_REGNUM 36          /* Contains Shadow Next Instruction Pointer */
 200 #define PC_REGNUM SXIP_REGNUM   /* Program Counter */
 201 #define NPC_REGNUM SNIP_REGNUM  /* Next Program Counter */
 202 #define PSR_REGNUM 32           /* Processor Status Register */
 203 #define FPSR_REGNUM 33          /* Floating Point Status Register */
 204 #define FPCR_REGNUM 34          /* Floating Point Control Register */
 205 #define SFIP_REGNUM 37          /* Contains Shadow Fetched Intruction pointer */
 206 #define NNPC_REGNUM SFIP_REGNUM /* Next Next Program Counter */
 207
 208 /* PSR status bit definitions.  */
 209
 210 #define PSR_MODE                0x80000000
 211 #define PSR_BYTE_ORDER          0x40000000
 212 #define PSR_SERIAL_MODE         0x20000000
 213 #define PSR_CARRY               0x10000000
 214 #define PSR_SFU_DISABLE         0x000003f0
 215 #define PSR_SFU1_DISABLE        0x00000008
 216 #define PSR_MXM                 0x00000004
 217 #define PSR_IND                 0x00000002
 218 #define PSR_SFRZ                0x00000001
 219
 220 /* BCS requires that the SXIP_REGNUM (or PC_REGNUM) contain the address
 221    of the next instr to be executed when a breakpoint occurs.  Because
 222    the kernel gets the next instr (SNIP_REGNUM), the instr in SNIP needs
 223    to be put back into SFIP, and the instr in SXIP should be shifted
 224    to SNIP */
 225
 226 /* Are you sitting down?  It turns out that the 88K BCS (binary compatibility
 227   standard) folks originally felt that the debugger should be responsible
 228   for backing up the IPs, not the kernel (as is usually done).  Well, they
 229   have reversed their decision, and in future releases our kernel will be
 230   handling the backing up of the IPs.  So, eventually, we won't need to
 231   do the SHIFT_INST_REGS stuff.  But, for now, since there are 88K systems out
 232   there that do need the debugger to do the IP shifting, and since there
 233   will be systems where the kernel does the shifting, the code is a little
 234   more complex than perhaps it needs to be (we still go inside SHIFT_INST_REGS,
 235   and if the shifting hasn't occurred then gdb goes ahead and shifts).  */
 236
 237 #define SHIFT_INST_REGS
 238
 239 /* Total amount of space needed to store our copies of the machine's
 240    register state, the array `registers'.  */
 241
 242 #define REGISTER_BYTES (NUM_REGS * sizeof(REGISTER_TYPE))
 243
 244 /* Index within `registers' of the first byte of the space for
 245    register N.  */
 246
 247 #define REGISTER_BYTE(N) ((N)*sizeof(REGISTER_TYPE))
 248
 249 /* Number of bytes of storage in the actual machine representation
 250    for register N.  */
 251
 252 #define REGISTER_RAW_SIZE(N) (sizeof(REGISTER_TYPE))
 253
 254 /* Number of bytes of storage in the program's representation
 255    for register N. */
 256
 257 #define REGISTER_VIRTUAL_SIZE(N) (sizeof(REGISTER_TYPE))
 258
 259 /* Largest value REGISTER_RAW_SIZE can have.  */
 260
 261 #define MAX_REGISTER_RAW_SIZE (sizeof(REGISTER_TYPE))
 262
 263 /* Largest value REGISTER_VIRTUAL_SIZE can have.
 264 /* Are FPS1, FPS2, FPR "virtual" regisers? */
 265
 266 #define MAX_REGISTER_VIRTUAL_SIZE (sizeof(REGISTER_TYPE))
 267
 268 /* Nonzero if register N requires conversion
 269    from raw format to virtual format.  */
 270
 271 #define REGISTER_CONVERTIBLE(N) (0)
 272
 273 /* Convert data from raw format for register REGNUM
 274    to virtual format for register REGNUM.  */
 275
 276 #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO) {bcopy ((FROM), (TO), (sizeof(REGISTER_TYPE)));}
 277
 278 /* Convert data from virtual format for register REGNUM
 279    to raw format for register REGNUM.  */
 280
 281 #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO) {bcopy ((FROM), (TO), (sizeof(REGISTER_TYPE)));}
 282
 283 /* Return the GDB type object for the "standard" data type
 284    of data in register N.  */
 285
 286 #define REGISTER_VIRTUAL_TYPE(N) (builtin_type_int)
 287
 288 /* The 88k call/return conventions call for "small" values to be returned
 289    into consecutive registers starting from r2.  */
 290
 291 #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
 292   bcopy (&(((char *)REGBUF)[REGISTER_BYTE(RV_REGNUM)]), (VALBUF), TYPE_LENGTH (TYPE))
 293
 294 #define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF) (*(int *)(REGBUF))
 295
 296 /* Write into appropriate registers a function return value
 297    of type TYPE, given in virtual format.  */
 298
 299 #define STORE_RETURN_VALUE(TYPE,VALBUF) \
 300   write_register_bytes (2*sizeof(void*), (VALBUF), TYPE_LENGTH (TYPE))
 301
 302 /* In COFF, if PCC says a parameter is a short or a char, do not
 303    change it to int (it seems the convention is to change it). */
 304
 305 #define BELIEVE_PCC_PROMOTION 1
 306
 307 /* Describe the pointer in each stack frame to the previous stack frame
 308    (its caller).  */
 309
 310 /* FRAME_CHAIN takes a frame's nominal address
 311    and produces the frame's chain-pointer.
 312
 313    However, if FRAME_CHAIN_VALID returns zero,
 314    it means the given frame is the outermost one and has no caller.  */
 315
 316 extern CORE_ADDR frame_chain ();
 317 extern int frame_chain_valid ();
 318 extern int frameless_function_invocation ();
 319
 320 #define FRAME_CHAIN(thisframe) \
 321         frame_chain (thisframe)
 322
 323 #define FRAME_CHAIN_VALID(chain, thisframe)     \
 324         frame_chain_valid (chain, thisframe)
 325
 326 #define FRAMELESS_FUNCTION_INVOCATION(frame, fromleaf)  \
 327         fromleaf = frameless_function_invocation (frame)
 328
 329 /* Define other aspects of the stack frame.  */
 330
 331 #define FRAME_SAVED_PC(FRAME)   \
 332         frame_saved_pc (FRAME)
 333 extern CORE_ADDR frame_saved_pc ();
 334
 335 #define FRAME_ARGS_ADDRESS(fi)  \
 336         frame_args_address (fi)
 337 extern CORE_ADDR frame_args_address ();
 338
 339 #define FRAME_LOCALS_ADDRESS(fi) \
 340         frame_locals_address (fi)
 341 extern CORE_ADDR frame_locals_address ();
 342
 343 /* Return number of args passed to a frame.
 344    Can return -1, meaning no way to tell.  */
 345
 346 #define FRAME_NUM_ARGS(numargs, fi)  ((numargs) = -1)
 347
 348 /* Return number of bytes at start of arglist that are not really args.  */
 349
 350 #define FRAME_ARGS_SKIP 0
 351
 352 /* Put here the code to store, into a struct frame_saved_regs,
 353    the addresses of the saved registers of frame described by FRAME_INFO.
 354    This includes special registers such as pc and fp saved in special
 355    ways in the stack frame.  sp is even more special:
 356    the address we return for it IS the sp for the next frame.  */
 357
 358 /* On the 88k, parameter registers get stored into the so called "homing"
 359    area.  This *always* happens when you compiled with GCC and use -g.
 360    Also, (with GCC and -g) the saving of the parameter register values
 361    always happens right within the function prologue code, so these register
 362    values can generally be relied upon to be already copied into their
 363    respective homing slots by the time you will normally try to look at
 364    them (we hope).
 365
 366    Note that homing area stack slots are always at *positive* offsets from
 367    the frame pointer.  Thus, the homing area stack slots for the parameter
 368    registers (passed values) for a given function are actually part of the
 369    frame area of the caller.  This is unusual, but it should not present
 370    any special problems for GDB.
 371
 372    Note also that on the 88k, we are only interested in finding the
 373    registers that might have been saved in memory.  This is a subset of
 374    the whole set of registers because the standard calling sequence allows
 375    the called routine to clobber many registers.
 376
 377    We could manage to locate values for all of the so called "preserved"
 378    registers (some of which may get saved within any particular frame) but
 379    that would require decoding all of the tdesc information.  Tht would be
 380    nice information for GDB to have, but it is not strictly manditory if we
 381    can live without the ability to look at values within (or backup to)
 382    previous frames.
 383 */
 384
 385 #define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs) \
 386         frame_find_saved_regs (frame_info, &frame_saved_regs)
 387
 388 \f
 389 /* There is not currently a functioning way to call functions in the
 390    inferior.  */
 391
 392 /* But if there was this is where we'd put the call dummy.  */
 393 /* #define CALL_DUMMY_LOCATION AFTER_TEXT_END */
 394
 395 /* When popping a frame on the 88k (say when doing a return command), the
 396    calling function only expects to have the "preserved" registers restored.
 397    Thus, those are the only ones that we even try to restore here.   */
 398
 399 #define POP_FRAME pop_frame ()
 400 extern void pop_frame ();