gdb/tm-29k.h

   1 /* Parameters for target machine of AMD 29000, for GDB, the GNU debugger.
   2    Copyright 1990, 1991 Free Software Foundation, Inc.
   3    Contributed by Cygnus Support.  Written by Jim Kingdon.
   4
   5 This file is part of GDB.
   6
   7 GDB is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 1, or (at your option)
  10 any later version.
  11
  12 GDB is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GDB; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 /* Parameters for an EB29K (a board which plugs into a PC and is
  22    accessed through EBMON software running on the PC, which we
  23    use as we'd use a remote stub (see remote-eb.c).
  24
  25    If gdb is ported to other 29k machines/systems, the
  26    machine/system-specific parts should be removed from this file (a
  27    la tm-68k.h).  */
  28
  29 /* Byte order is configurable, but this machine runs big-endian.  */
  30 #define TARGET_BYTE_ORDER BIG_ENDIAN
  31
  32 /* Floating point uses IEEE representations.  */
  33 #define IEEE_FLOAT
  34
  35 /* We can either use a.out, encapsulated, or can use COFF */
  36 #ifndef COFF_ENCAPSULATE
  37 #define COFF_FORMAT
  38 /* This just has to do with what coff header files are in use.  */
  39 #define COFF_CHECK_X_ZEROES
  40 #endif
  41
  42 /* Recognize our magic number.  */
  43 #define BADMAG(x) ((x)->f_magic != 0572)
  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(pc) \
  59   { pc = skip_prologue (pc); }
  60 CORE_ADDR skip_prologue ();
  61
  62 /* Immediately after a function call, return the saved pc.
  63    Can't go through the frames for this because on some machines
  64    the new frame is not set up until the new function executes
  65    some instructions.  */
  66
  67 #define SAVED_PC_AFTER_CALL(frame) (read_register (LR0_REGNUM))
  68
  69 /* I'm not sure about the exact value of this, but based on looking
  70    at the stack pointer when we get to main this seems to be right.
  71
  72    This is the register stack; We call it "CONTROL" in GDB for consistency
  73    with Pyramid.  */
  74 #define CONTROL_END_ADDR 0x80200000
  75
  76 /* Memory stack.  This is for the default register stack size, which is
  77    only 0x800 bytes.  Perhaps we should let the user specify stack sizes
  78    (and tell EBMON with the "ZS" command).  */
  79 #define STACK_END_ADDR 0x801ff800
  80
  81 /* Stack grows downward.  */
  82
  83 #define INNER_THAN <
  84
  85 /* Stack must be aligned on 32-bit word boundaries.  */
  86 #define STACK_ALIGN(ADDR) (((ADDR) + 3) & ~3)
  87
  88 /* Sequence of bytes for breakpoint instruction.  */
  89 /* ASNEQ 0x50, gr1, gr1
  90    The trap number 0x50 is chosen arbitrarily.  */
  91 #if TARGET_BYTE_ORDER == BIG_ENDIAN
  92 #define BREAKPOINT {0x72, 0x50, 0x01, 0x01}
  93 #else /* Target is little-endian.  */
  94 #define BREAKPOINT {0x01, 0x01, 0x50, 0x72}
  95 #endif /* Target is little-endian.  */
  96
  97 /* Amount PC must be decremented by after a breakpoint.
  98    This is often the number of bytes in BREAKPOINT
  99    but not always.  */
 100
 101 #define DECR_PC_AFTER_BREAK 4
 102
 103 /* Nonzero if instruction at PC is a return instruction.
 104    On the 29k, this is a "jmpi l0" instruction.  */
 105
 106 #define ABOUT_TO_RETURN(pc) \
 107   ((read_memory_integer (pc, 4) & 0xff0000ff) == 0xc0000080)
 108
 109 /* Return 1 if P points to an invalid floating point value.  */
 110
 111 #define INVALID_FLOAT(p, len) 0   /* Just a first guess; not checked */
 112
 113 /* Say how long (ordinary) registers are.  */
 114
 115 #define REGISTER_TYPE long
 116
 117 /* Number of machine registers */
 118
 119 #define NUM_REGS 205
 120
 121 /* Initializer for an array of names of registers.
 122    There should be NUM_REGS strings in this initializer.
 123
 124    FIXME, add floating point registers and support here.
 125
 126    Also note that this list does not attempt to deal with kernel
 127    debugging (in which the first 32 registers are gr64-gr95).  */
 128
 129 #define REGISTER_NAMES \
 130 {"gr96", "gr97", "gr98", "gr99", "gr100", "gr101", "gr102", "gr103", "gr104", \
 131  "gr105", "gr106", "gr107", "gr108", "gr109", "gr110", "gr111", "gr112", \
 132  "gr113", "gr114", "gr115", "gr116", "gr117", "gr118", "gr119", "gr120", \
 133  "gr121", "gr122", "gr123", "gr124", "gr125", "gr126", "gr127",          \
 134  "lr0", "lr1", "lr2", "lr3", "lr4", "lr5", "lr6", "lr7", "lr8", "lr9",   \
 135  "lr10", "lr11", "lr12", "lr13", "lr14", "lr15", "lr16", "lr17", "lr18", \
 136  "lr19", "lr20", "lr21", "lr22", "lr23", "lr24", "lr25", "lr26", "lr27", \
 137  "lr28", "lr29", "lr30", "lr31", "lr32", "lr33", "lr34", "lr35", "lr36", \
 138  "lr37", "lr38", "lr39", "lr40", "lr41", "lr42", "lr43", "lr44", "lr45", \
 139  "lr46", "lr47", "lr48", "lr49", "lr50", "lr51", "lr52", "lr53", "lr54", \
 140  "lr55", "lr56", "lr57", "lr58", "lr59", "lr60", "lr61", "lr62", "lr63", \
 141  "lr64", "lr65", "lr66", "lr67", "lr68", "lr69", "lr70", "lr71", "lr72", \
 142  "lr73", "lr74", "lr75", "lr76", "lr77", "lr78", "lr79", "lr80", "lr81", \
 143  "lr82", "lr83", "lr84", "lr85", "lr86", "lr87", "lr88", "lr89", "lr90", \
 144  "lr91", "lr92", "lr93", "lr94", "lr95", "lr96", "lr97", "lr98", "lr99", \
 145  "lr100", "lr101", "lr102", "lr103", "lr104", "lr105", "lr106", "lr107", \
 146  "lr108", "lr109", "lr110", "lr111", "lr112", "lr113", "lr114", "lr115", \
 147  "lr116", "lr117", "lr118", "lr119", "lr120", "lr121", "lr122", "lr123", \
 148  "lr124", "lr125", "lr126", "lr127",                                     \
 149   "AI0", "AI1", "AI2", "AI3", "AI4", "AI5", "AI6", "AI7", "AI8", "AI9",  \
 150   "AI10", "AI11", "AI12", "AI13", "AI14", "AI15", "FP",                  \
 151   "bp", "fc", "cr", "q",                                                 \
 152   "vab", "ops", "cps", "cfg", "cha", "chd", "chc", "rbp", "tmc", "tmr",  \
 153   "pc0", "pc1", "pc2", "mmu", "lru", "fpe", "int", "fps", "exo", "gr1",  \
 154   "alu", "ipc", "ipa", "ipb" }
 155
 156 /* Special register #x.  */
 157 #define SR_REGNUM(x) \
 158   ((x) < 15  ? VAB_REGNUM + (x)                                  \
 159    : (x) >= 128 && (x) < 131 ? IPC_REGNUM + (x)                  \
 160    : (x) == 131 ? Q_REGNUM                                       \
 161    : (x) == 132 ? ALU_REGNUM                                     \
 162    : (x) >= 133 && (x) < 136 ? BP_REGNUM + (x)                   \
 163    : (x) >= 160 && (x) < 163 ? FPE_REGNUM + (x)                  \
 164    : (x) == 164 ? EXO_REGNUM                                     \
 165    : (error ("Internal error in SR_REGNUM"), 0))
 166 #define GR96_REGNUM 0
 167 #define GR1_REGNUM 200
 168 /* This needs to be the memory stack pointer, not the register stack pointer,
 169    to make call_function work right.  */
 170 #define SP_REGNUM MSP_REGNUM
 171 #define FP_REGNUM 33 /* lr1 */
 172 /* Large Return Pointer (gr123).  */
 173 #define LRP_REGNUM (123 - 96 + GR96_REGNUM)
 174 /* Static link pointer (gr124).  */
 175 #define SLP_REGNUM (124 - 96 + GR96_REGNUM)
 176 /* Memory Stack Pointer (gr125).  */
 177 #define MSP_REGNUM (125 - 96 + GR96_REGNUM)
 178 /* Register allocate bound (gr126).  */
 179 #define RAB_REGNUM (126 - 96 + GR96_REGNUM)
 180 /* Register Free Bound (gr127).  */
 181 #define RFB_REGNUM (127 - 96 + GR96_REGNUM)
 182 /* Register Stack Pointer.  */
 183 #define RSP_REGNUM GR1_REGNUM
 184 #define LR0_REGNUM 32
 185 #define PC_REGNUM 192 /* pc1 */
 186 #define NPC_REGNUM 191 /* pc0 */
 187 #define PC2_REGNUM 193
 188 #define BP_REGNUM 177
 189 #define FC_REGNUM 178
 190 #define CR_REGNUM 179
 191 #define Q_REGNUM 180
 192 #define VAB_REGNUM 181
 193 #define LRU_REGNUM 195
 194 #define FPE_REGNUM 196
 195 #define INT_REGNUM 197
 196 #define FPS_REGNUM 198
 197 #define EXO_REGNUM 199
 198 #define PS_REGNUM 201
 199 #define ALU_REGNUM 201
 200 #define IPC_REGNUM 202
 201 #define IPB_REGNUM 204
 202
 203 /* Total amount of space needed to store our copies of the machine's
 204    register state, the array `registers'.  */
 205 #define REGISTER_BYTES (NUM_REGS * 4)
 206
 207 /* Index within `registers' of the first byte of the space for
 208    register N.  */
 209 #define REGISTER_BYTE(N)  ((N)*4)
 210
 211 /* Number of bytes of storage in the actual machine representation
 212    for register N.  */
 213
 214 /* All regs are 4 bytes.  */
 215
 216 #define REGISTER_RAW_SIZE(N) (4)
 217
 218 /* Number of bytes of storage in the program's representation
 219    for register N.  */
 220
 221 /* All regs are 4 bytes.  */
 222
 223 #define REGISTER_VIRTUAL_SIZE(N) (4)
 224
 225 /* Largest value REGISTER_RAW_SIZE can have.  */
 226
 227 #define MAX_REGISTER_RAW_SIZE (4)
 228
 229 /* Largest value REGISTER_VIRTUAL_SIZE can have.  */
 230
 231 #define MAX_REGISTER_VIRTUAL_SIZE (4)
 232
 233 /* Nonzero if register N requires conversion
 234    from raw format to virtual format.  */
 235
 236 #define REGISTER_CONVERTIBLE(N) (0)
 237
 238 /* Convert data from raw format for register REGNUM
 239    to virtual format for register REGNUM.  */
 240
 241 #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO) \
 242 { bcopy ((FROM), (TO), 4); }
 243
 244 /* Convert data from virtual format for register REGNUM
 245    to raw format for register REGNUM.  */
 246
 247 #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO) \
 248 { bcopy ((FROM), (TO), 4); }
 249
 250 /* Return the GDB type object for the "standard" data type
 251    of data in register N.  */
 252
 253 #define REGISTER_VIRTUAL_TYPE(N) \
 254   (((N) == PC_REGNUM || (N) == LRP_REGNUM || (N) == SLP_REGNUM         \
 255     || (N) == MSP_REGNUM || (N) == RAB_REGNUM || (N) == RFB_REGNUM     \
 256     || (N) == GR1_REGNUM || (N) == FP_REGNUM || (N) == LR0_REGNUM       \
 257     || (N) == NPC_REGNUM || (N) == PC2_REGNUM)                           \
 258    ? lookup_pointer_type (builtin_type_void) : builtin_type_int)
 259 \f
 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 /* On the 29k the LRP points to the part of the structure beyond the first
 263    16 words.  */
 264 #define STORE_STRUCT_RETURN(ADDR, SP) \
 265   write_register (LRP_REGNUM, (ADDR) + 16 * 4);
 266
 267 /* Should call_function allocate stack space for a struct return?  */
 268 /* On the 29k objects over 16 words require the caller to allocate space.  */
 269 #define USE_STRUCT_CONVENTION(gcc_p, type) (TYPE_LENGTH (type) > 16 * 4)
 270
 271 /* Extract from an array REGBUF containing the (raw) register state
 272    a function return value of type TYPE, and copy that, in virtual format,
 273    into VALBUF.  */
 274
 275 #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF)              \
 276   {                                                                        \
 277     int reg_length = TYPE_LENGTH (TYPE);                                   \
 278     if (reg_length > 16 * 4)                                               \
 279       {                                                                    \
 280         reg_length = 16 * 4;                                               \
 281         read_memory (*((int *)(REGBUF) + LRP_REGNUM), (VALBUF) + 16 * 4,   \
 282                      TYPE_LENGTH (TYPE) - 16 * 4);                         \
 283       }                                                                    \
 284     bcopy (((int *)(REGBUF))+GR96_REGNUM, (VALBUF), reg_length);           \
 285   }
 286
 287 /* Write into appropriate registers a function return value
 288    of type TYPE, given in virtual format.  */
 289
 290 #define STORE_RETURN_VALUE(TYPE,VALBUF) \
 291   {                                                                       \
 292     int reg_length = TYPE_LENGTH (TYPE);                                  \
 293     if (reg_length > 16 * 4)                                              \
 294       {                                                                   \
 295         reg_length = 16 * 4;                                              \
 296         write_memory (read_register (LRP_REGNUM),                         \
 297                       (char *)(VALBUF) + 16 * 4,                          \
 298                       TYPE_LENGTH (TYPE) - 16 * 4);                       \
 299       }                                                                   \
 300     write_register_bytes (REGISTER_BYTE (GR96_REGNUM), (char *)(VALBUF),  \
 301                           TYPE_LENGTH (TYPE));                            \
 302   }
 303 \f
 304 /* The am29k user's guide documents well what the stacks look like.
 305    But what isn't so clear there is how this interracts with the
 306    symbols, or with GDB.
 307    In the following saved_msp, saved memory stack pointer (which functions
 308    as a memory frame pointer), means either
 309    a register containing the memory frame pointer or, in the case of
 310    functions with fixed size memory frames (i.e. those who don't use
 311    alloca()), the result of the calculation msp + msize.
 312
 313    LOC_ARG, LOC_LOCAL - For GCC, these are relative to saved_msp.
 314      For high C, these are relative to msp (making alloca impossible).
 315    LOC_REGISTER, LOC_REGPARM - The register number is the number at the
 316      time the function is running (after the prologue), or in the case
 317      of LOC_REGPARM, may be a register number in the range 160-175.
 318
 319    The compilers do things like store an argument into memory, and then put out
 320    a LOC_ARG for it, or put it into global registers and put out a
 321    LOC_REGPARM.  Thus is it important to execute the first line of
 322    code (i.e. the line of the open brace, i.e. the prologue) of a function
 323    before trying to print arguments or anything.
 324
 325    The following diagram attempts to depict what is going on in memory
 326    (see also the _am29k user's guide_) and also how that interacts with
 327    GDB frames.  We arbitrarily pick fci->frame to point the same place
 328    as the register stack pointer; since we set it ourself in
 329    INIT_EXTRA_FRAME_INFO, and access it only through the FRAME_*
 330    macros, it doesn't really matter exactly how we
 331    do it.  However, note that FRAME_FP is used in two ways in GDB:
 332    (1) as a "magic cookie" which uniquely identifies frames (even over
 333    calls to the inferior), (2) (in PC_IN_CALL_DUMMY [!CANNOT_EXECUTE_STACK])
 334    as the value of SP_REGNUM before the dummy frame was pushed.  These
 335    two meanings would be incompatible for the 29k if we didn't define
 336    CANNOT_EXECUTE_STACK (but we do, so don't worry about it).
 337    Also note that "lr1" below, while called a frame pointer
 338    in the user's guide, has only one function:  To determine whether
 339    registers need to be filled in the function epilogue.
 340
 341    Consider the code:
 342               < call bar>
 343         loc1: . . .
 344         bar:  sub gr1,gr1,rsize_b
 345               . . .
 346               add mfp,msp,0
 347               sub msp,msp,msize_b
 348               . . .
 349               < call foo >
 350         loc2: . . .
 351         foo:  sub gr1,gr1,rsize_f
 352               . . .
 353               add mfp,msp,0
 354               sub msp,msp,msize_f
 355               . . .
 356         loc3: < suppose the inferior stops here >
 357
 358                    memory stack      register stack
 359                    |           |     |____________|
 360                    |           |     |____loc1____|
 361           +------->|___________|     |            |   ^
 362           |        | ^         |     |  locals_b  |   |
 363           |        | |         |     |____________|   |
 364           |        | |         |     |            |   | rsize_b
 365           |        | | msize_b |     | args_to_f  |   |
 366           |        | |         |     |____________|   |
 367           |        | |         |     |____lr1_____|   V
 368           |        | V         |     |____loc2____|<----------------+
 369           |   +--->|___________|<---------mfp     |   ^             |
 370           |   |    | ^         |     |  locals_f  |   |             |
 371           |   |    | | msize_f |     |____________|   |             |
 372           |   |    | |         |     |            |   | rsize_f     |
 373           |   |    | V         |     |   args     |   |             |
 374           |   |    |___________|<msp |____________|   |             |
 375           |   |                      |_____lr1____|   V             |
 376           |   |                      |___garbage__| <- gr1 <----+   |
 377           |   |                                                 |   |
 378           |   |                                                 |   |
 379           |   |                      pc=loc3                    |   |
 380           |   |                                                 |   |
 381           |   |                                                 |   |
 382           |   |            frame cache                          |   |
 383           |   |       |_________________|                       |   |
 384           |   |       |rsize=rsize_b    |                       |   |
 385           |   |       |msize=msize_b    |                       |   |
 386           +---|--------saved_msp        |                       |   |
 387               |       |frame------------------------------------|---+
 388               |       |pc=loc2          |                       |
 389               |       |_________________|                       |
 390               |       |rsize=rsize_f    |                       |
 391               |       |msize=msize_f    |                       |
 392               +--------saved_msp        |                       |
 393                       |frame------------------------------------+
 394                       |pc=loc3          |
 395                       |_________________|
 396
 397    So, is that sufficiently confusing?  Welcome to the 29000.
 398    Notes:
 399    * The frame for foo uses a memory frame pointer but the frame for
 400      bar does not.  In the latter case the saved_msp is
 401      computed by adding msize to the saved_msp of the
 402      next frame.
 403    * msize is in the frame cache only for high C's sake.  */
 404
 405 void read_register_stack ();
 406 long read_register_stack_integer ();
 407 \f
 408 #define EXTRA_FRAME_INFO  \
 409   CORE_ADDR saved_msp;    \
 410   unsigned int rsize;     \
 411   unsigned int msize;
 412
 413 /* Because INIT_FRAME_PC gets passed fromleaf, that's where we init
 414    not only ->pc and ->frame, but all the extra stuff, when called from
 415    get_prev_frame_info, that is.  */
 416 #define INIT_EXTRA_FRAME_INFO(fci) \
 417   init_extra_frame_info(fci);
 418 void init_extra_frame_info ();
 419 #define INIT_FRAME_PC(fromleaf, fci) \
 420   init_frame_pc(fromleaf, fci);
 421 void init_frame_pc ();
 422 \f
 423 /* FRAME_CHAIN takes a FRAME
 424    and produces the frame's chain-pointer.
 425
 426    FRAME_CHAIN_COMBINE takes the chain pointer and the frame's nominal address
 427    and produces the nominal address of the caller frame.
 428
 429    However, if FRAME_CHAIN_VALID returns zero,
 430    it means the given frame is the outermost one and has no caller.
 431    In that case, FRAME_CHAIN_COMBINE is not used.  */
 432
 433 /* On the 29k, the nominal address of a frame is the address on the
 434    register stack of the return address (the one next to the incoming
 435    arguments, not down at the bottom so nominal address == stack pointer).
 436
 437    GDB expects "nominal address" to equal contents of FP_REGNUM,
 438    at least when it comes time to create the innermost frame.
 439    However, that doesn't work for us, so when creating the innermost
 440    frame we set ->frame ourselves in INIT_EXTRA_FRAME_INFO.  */
 441
 442 /* These are mostly dummies for the 29k because INIT_FRAME_PC
 443    sets prev->frame instead.  */
 444 #define FRAME_CHAIN(thisframe) (0)
 445
 446 /* Not sure how to figure out where the bottom frame is.  There is
 447    no frame for start.  In my tests so far the
 448    pc has been outside the text segment, though, so check for that.
 449    However, allow a pc in a call dummy.  */
 450 #define FRAME_CHAIN_VALID(chain, thisframe) \
 451   (outside_startup_file (FRAME_SAVED_PC (thisframe))   \
 452    && FRAME_SAVED_PC (thisframe) >= text_start         \
 453    && FRAME_SAVED_PC (thisframe) < text_end + CALL_DUMMY_LENGTH)
 454
 455 #define FRAME_CHAIN_COMBINE(chain, thisframe) (0)
 456
 457 /* Define other aspects of the stack frame.  */
 458
 459 /* A macro that tells us whether the function invocation represented
 460    by FI does not have a frame on the stack associated with it.  If it
 461    does not, FRAMELESS is set to 1, else 0.  */
 462 #define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) \
 463   (FRAMELESS) = frameless_look_for_prologue(FI)
 464
 465 /* Saved pc (i.e. return address).  */
 466 #define FRAME_SAVED_PC(fraim) \
 467   (read_register_stack_integer ((fraim)->frame + (fraim)->rsize, 4))
 468
 469 /* Local variables (i.e. LOC_LOCAL) are on the memory stack, with their
 470    offsets being relative to the memory stack pointer (high C) or
 471    saved_msp (gcc).  */
 472
 473 #define FRAME_LOCALS_ADDRESS(fi) frame_locals_address (fi)
 474 extern CORE_ADDR frame_locals_address ();
 475
 476 /* Return number of args passed to a frame.
 477    Can return -1, meaning no way to tell.  */
 478 /* While we could go the effort of finding the tags word and getting
 479    the argcount field from it,
 480    (1) It only counts arguments in registers, i.e. the first 16 words
 481        of arguments
 482    (2) It gives the number of arguments the function was declared with
 483        not how many it was called with (or some variation, like all 16
 484        words for varadic functions).  This makes argcount pretty much
 485        redundant with -g info, even for varadic functions.
 486    So don't bother.  */
 487 #define FRAME_NUM_ARGS(numargs, fi) ((numargs) = -1)
 488
 489 #define FRAME_ARGS_ADDRESS(fi) FRAME_LOCALS_ADDRESS (fi)
 490
 491 /* Return number of bytes at start of arglist that are not really args.  */
 492
 493 #define FRAME_ARGS_SKIP 0
 494
 495 /* Provide our own get_saved_register.  HAVE_REGISTER_WINDOWS is insufficient
 496    because registers get renumbered on the 29k without getting saved.  */
 497
 498 #define GET_SAVED_REGISTER
 499 \f
 500 /* Call function stuff.  */
 501
 502 /* The dummy frame looks like this (see also the general frame picture
 503    above):
 504
 505                                         register stack
 506
 507                                       |                |  frame for function
 508                                       |   locals_sproc |  executing at time
 509                                       |________________|  of call_function.
 510                                       |                |  We must not disturb
 511                                       | args_out_sproc |  it.
 512         memory stack                  |________________|
 513                                       |____lr1_sproc___|
 514        |            |                 |__retaddr_sproc_| <- gr1 (at start)
 515        |____________|<-msp 0 <-----------mfp_dummy_____|
 516        |            |  (at start)     |                |
 517        | arg_slop   |                 |  saved regs    |
 518        | (16 words) |                 | gr96-gr124     |
 519        |____________|<-msp 1--after   | sr128-sr135    |
 520        |            | PUSH_DUMMY_FRAME|                |
 521        | struct ret |                 |________________|
 522        | 17+        |                 |                |
 523        |____________|<- lrp           | args_out_dummy |
 524        | struct ret |                 |  (16 words)    |
 525        | 16         |                 |________________|
 526        | (16 words) |                 |____lr1_dummy___|
 527        |____________|<- msp 2--after  |_retaddr_dummy__|<- gr1 after
 528        |            | struct ret      |                |   PUSH_DUMMY_FRAME
 529        | margs17+   | area allocated  |  locals_inf    |
 530        |            |                 |________________|    called
 531        |____________|<- msp 4--when   |                |    function's
 532        |            |   inf called    | args_out_inf   |    frame (set up
 533        | margs16    |                 |________________|    by called
 534        | (16 words) |                 |_____lr1_inf____|    function).
 535        |____________|<- msp 3--after  |       .        |
 536        |            |   args pushed   |       .        |
 537        |            |                 |       .        |
 538                                       |                |
 539
 540    arg_slop: This area is so that when the call dummy adds 16 words to
 541       the msp, it won't end up larger than mfp_dummy (it is needed in the
 542       case where margs and struct_ret do not add up to at least 16 words).
 543    struct ret:  This area is allocated by GDB if the return value is more
 544       than 16 words.  struct ret_16 is not used on the 29k.
 545    margs:  Pushed by GDB.  The call dummy copies the first 16 words to
 546       args_out_dummy.
 547    retaddr_sproc:  Contains the PC at the time we call the function.
 548       set by PUSH_DUMMY_FRAME and read by POP_FRAME.
 549    retaddr_dummy:  This points to a breakpoint instruction in the dummy.  */
 550 \f
 551 /* Rsize for dummy frame, in bytes.  */
 552
 553 /* Bytes for outgoing args, lr1, and retaddr.  */
 554 #define DUMMY_ARG (2 * 4 + 16 * 4)
 555
 556 /* Number of special registers (sr128-) to save.  */
 557 #define DUMMY_SAVE_SR128 8
 558 /* Number of general (gr96-) registers to save.  */
 559 #define DUMMY_SAVE_GR96 29
 560
 561 #define DUMMY_FRAME_RSIZE \
 562 (4 /* mfp_dummy */                                 \
 563  + DUMMY_SAVE_GR96 * 4                             \
 564  + DUMMY_SAVE_SR128 * 4                            \
 565  + DUMMY_ARG                                       \
 566  )
 567
 568 /* Push an empty stack frame, to record the current PC, etc.  */
 569
 570 #define PUSH_DUMMY_FRAME push_dummy_frame();
 571 extern void push_dummy_frame ();
 572
 573 /* Discard from the stack the innermost frame,
 574    restoring all saved registers.  */
 575
 576 #define POP_FRAME pop_frame ();
 577 extern void pop_frame ();
 578
 579 /* This sequence of words is the instructions
 580    mtsrim cr, 15
 581    loadm 0, 0, lr2, msp     ; load first 16 words of arguments into registers
 582    add msp, msp, 16 * 4     ; point to the remaining arguments
 583   CONST_INSN:
 584    const gr96,inf
 585    consth gr96,inf
 586    calli lr0, gr96
 587    aseq 0x40,gr1,gr1   ; nop
 588    asneq 0x50,gr1,gr1  ; breakpoint
 589    */
 590
 591 /* Position of the "const" instruction within CALL_DUMMY in bytes.  */
 592 #define CONST_INSN (3 * 4)
 593 #if TARGET_BYTE_ORDER == HOST_BYTE_ORDER
 594 #define CALL_DUMMY {0x0400870f, 0x3600827d, 0x157d7d40, 0x03ff60ff,    \
 595                     0x02ff60ff, 0xc8008060, 0x70400101, 0x72500101}
 596 #else /* Byte order differs.  */
 597   you lose
 598 #endif /* Byte order differs.  */
 599 #define CALL_DUMMY_LENGTH (8 * 4)
 600
 601 #define CALL_DUMMY_START_OFFSET 0  /* Start execution at beginning of dummy */
 602
 603 /* Helper macro for FIX_CALL_DUMMY.  WORDP is a long * which points to a
 604    word in target byte order; bits 0-7 and 16-23 of *WORDP are replaced with
 605    bits 0-7 and 8-15 of DATA (which is in host byte order).  */
 606
 607 #if TARGET_BYTE_ORDER == BIG_ENDIAN
 608 #define STUFF_I16(WORDP, DATA) \
 609   { \
 610     *((char *)(WORDP) + 3) = ((DATA) & 0xff);\
 611     *((char *)(WORDP) + 1) = (((DATA) >> 8) & 0xff);\
 612   }
 613 #else /* Target is little endian.  */
 614 #define STUFF_I16(WORDP, DATA) \
 615   {
 616     *(char *)(WORDP) = ((DATA) & 0xff);
 617     *((char *)(WORDP) + 2) = (((DATA) >> 8) & 0xff);
 618   }
 619 #endif /* Target is little endian.  */
 620
 621 /* Insert the specified number of args and function address
 622    into a call sequence of the above form stored at DUMMYNAME.  */
 623
 624 /* Currently this stuffs in the address of the function that we are calling.
 625    If different 29k systems use different breakpoint instructions, it
 626    could also stuff BREAKPOINT in the right place (to avoid having to
 627    duplicate CALL_DUMMY in each tm-*.h file).  */
 628
 629 #define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p)   \
 630   {\
 631     STUFF_I16((char *)dummyname + CONST_INSN, fun);\
 632     STUFF_I16((char *)dummyname + CONST_INSN + 4, fun >> 16);\
 633   }
 634
 635 /* At least our 29k board has separate data & instruction memories and can't
 636    execute the data memory.  Also, there should be space after text_end;
 637    we won't get a SIGSEGV or scribble on data space.  */
 638
 639 #define CALL_DUMMY_LOCATION AFTER_TEXT_END
 640
 641 /* How to translate register numbers in the .stab's into gdb's internal register
 642    numbers.  We don't translate them, but we warn if an invalid register
 643    number is seen.  Note that FIXME, we use the value "sym" as an implicit
 644    argument in printing the error message.  It happens to be available where
 645    this macro is used.  (This macro definition appeared in a late revision
 646    of gdb-3.91.6 and is not well tested.  Also, it should be a "complaint".) */
 647
 648 #define STAB_REG_TO_REGNUM(num) \
 649         (((num) > LR0_REGNUM + 127) \
 650            ? fprintf(stderr,    \
 651                 "Invalid register number %d in symbol table entry for %s\n", \
 652                  (num), SYMBOL_NAME (sym)), (num)       \
 653            : (num))