gdb/tm-rs6000.h

   1 /* Parameters for target execution on an RS6000, for GDB, the GNU debugger.
   2    Copyright (C) 1986, 1987, 1989, 1991 Free Software Foundation, Inc.
   3    Contributed by IBM Corporation.
   4
   5 This file is part of GDB.
   6
   7 This program 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 2 of the License, or
  10 (at your option) any later version.
  11
  12 This program 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 this program; if not, write to the Free Software
  19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21
  22 /* A successful ptrace(continue) might return errno != 0 in this particular port
  23    of rs6000. I am not sure why. We will use this kludge and ignore it until
  24    we figure out the real problem. */
  25
  26 #define AIX_BUGGY_PTRACE_CONTINUE       \
  27 { \
  28   int ret = ptrace (PT_CONTINUE, inferior_pid, \
  29                     (PTRACE_ARG3_TYPE) 1, signal, 0); \
  30   if (errno) { \
  31 /*    printf ("ret: %d, errno: %d, signal: %d\n", ret, errno, signal); */ \
  32     errno = 0; } \
  33 }
  34
  35 extern int      symtab_relocated;
  36
  37 /* Minimum possible text address in AIX */
  38
  39 #define TEXT_SEGMENT_BASE       0x10000000
  40
  41
  42 /* text addresses in a core file does not necessarily match to symbol table,
  43    if symbol table relocation wasn't done yet. */
  44
  45 #define CORE_NEEDS_RELOCATION(PC)       \
  46   if (!symtab_relocated && !inferior_pid && (PC) >  TEXT_SEGMENT_BASE)  \
  47     (PC) -= ( TEXT_SEGMENT_BASE + text_adjustment (exec_bfd));
  48
  49 /* Load segment of a given pc value. */
  50
  51 #define PC_LOAD_SEGMENT(PC)     pc_load_segment_name(PC)
  52
  53
  54 /* Conversion between a register number in stab string to actual register num. */
  55
  56 #define STAB_REG_TO_REGNUM(value)       (value)
  57
  58 /* return true if a given `pc' value is in `call dummy' function. */
  59
  60 #define PC_IN_CALL_DUMMY(STOP_PC, STOP_SP, STOP_FRAME_ADDR)     \
  61         (STOP_SP < STOP_PC && STOP_PC < STACK_END_ADDR)
  62
  63 /* For each symtab, we keep track of which BFD it came from.  */
  64 #define EXTRA_SYMTAB_INFO       \
  65         unsigned    nonreloc:1;         /* TRUE if non relocatable */
  66
  67 #define INIT_EXTRA_SYMTAB_INFO(symtab)  \
  68         symtab->nonreloc = 0;           \
  69
  70 extern unsigned int text_start, data_start;
  71 extern int inferior_pid;
  72 extern char *corefile;
  73
  74 /* setpgrp() messes up controling terminal. The other version of it
  75    requires libbsd.a. */
  76 #define setpgrp(XX,YY)          setpgid (XX, YY)
  77
  78 /* We are missing register descriptions in the system header files. Sigh! */
  79
  80 struct regs {
  81         int     gregs [32];             /* general purpose registers */
  82         int     pc;                     /* program conter       */
  83         int     ps;                     /* processor status, or machine state */
  84 };
  85
  86 struct fp_status {
  87         double  fpregs [32];            /* floating GP registers */
  88 };
  89
  90
  91 /* To be used by function_frame_info. */
  92
  93 struct aix_framedata {
  94   int   offset;                         /* # of bytes in gpr's and fpr's are saved */
  95   int   saved_gpr;                      /* smallest # of saved gpr */
  96   int   saved_fpr;                      /* smallest # of saved fpr */
  97   int   alloca_reg;                     /* alloca register number (frame ptr) */
  98   char  frameless;                      /* true if frameless functions. */
  99 };
 100
 101
 102 /* Define the byte order of the machine.  */
 103
 104 #define TARGET_BYTE_ORDER       BIG_ENDIAN
 105
 106 /* Define this if the C compiler puts an underscore at the front
 107    of external names before giving them to the linker.  */
 108
 109 #undef NAMES_HAVE_UNDERSCORE
 110
 111 /* AIX's assembler doesn't grok dollar signs in identifiers.
 112    So we use dots instead.  This item must be coordinated with G++. */
 113 #undef CPLUS_MARKER
 114 #define CPLUS_MARKER '.'
 115
 116 /* Offset from address of function to start of its code.
 117    Zero on most machines.  */
 118
 119 #define FUNCTION_START_OFFSET 0
 120
 121 /* Advance PC across any function entry prologue instructions
 122    to reach some "real" code.  */
 123
 124 #define SKIP_PROLOGUE(pc)       pc = skip_prologue (pc)
 125
 126 /* If PC is in some function-call trampoline code, return the PC
 127    where the function itself actually starts.  If not, return NULL.  */
 128
 129 #define SKIP_TRAMPOLINE_CODE(pc)        skip_trampoline_code (pc)
 130
 131 /* When a child process is just starting, we sneak in and relocate
 132    the symbol table (and other stuff) after the dynamic linker has
 133    figured out where they go. But we want to do this relocation just
 134    once. */
 135
 136 extern int loadinfotextindex;
 137
 138 #define SOLIB_CREATE_INFERIOR_HOOK(PID) \
 139   do {                                  \
 140     if (loadinfotextindex == 0) \
 141         xcoff_relocate_symtab (PID);    \
 142   } while (0)
 143
 144
 145 /* Number of trap signals we need to skip over, once the inferior process
 146    starts running. */
 147
 148 #define START_INFERIOR_TRAPS_EXPECTED   2
 149
 150 /* AIX might return a sigtrap, with a "stop after load" status. It should
 151    be ignored by gdb, shouldn't be mixed up with breakpoint traps. */
 152
 153 /* Another little glitch  in AIX is signal 0. I have no idea why wait(2)
 154    returns with this status word. It looks harmless. */
 155
 156 #define SIGTRAP_STOP_AFTER_LOAD(W)      \
 157  if ( (W) == 0x57c || (W) == 0x7f) {    \
 158    if ((W)==0x57c && breakpoints_inserted) {    \
 159      mark_breakpoints_out ();           \
 160      insert_breakpoints ();             \
 161      insert_step_breakpoint ();         \
 162    }                                    \
 163    resume (0, 0);                       \
 164    continue;                            \
 165  }
 166
 167 /* In xcoff, we cannot process line numbers when we see them. This is
 168    mainly because we don't know the boundaries of the include files. So,
 169    we postpone that, and then enter and sort(?) the whole line table at
 170    once, when we are closing the current symbol table in end_symtab(). */
 171
 172 #define PROCESS_LINENUMBER_HOOK()       aix_process_linenos ()
 173
 174
 175 /* When a target process or core-file has been attached, we sneak in
 176    and figure out where the shared libraries have got to. In case there
 177    is no inferior_process exists (e.g. bringing up a core file), we can't
 178    attemtp to relocate symbol table, since we don't have information about
 179    load segments. */
 180
 181 #define SOLIB_ADD(a, b, c)      \
 182    if (inferior_pid)    xcoff_relocate_symtab (inferior_pid)
 183
 184 /* Immediately after a function call, return the saved pc.
 185    Can't go through the frames for this because on some machines
 186    the new frame is not set up until the new function executes
 187    some instructions.  */
 188
 189 #define SAVED_PC_AFTER_CALL(frame)      \
 190         (register_valid [LR_REGNUM] ?   \
 191           (*(int*)&registers[REGISTER_BYTE (LR_REGNUM)]) :      \
 192           read_register (LR_REGNUM))
 193
 194 /*#define SAVED_PC_AFTER_CALL(frame)    saved_pc_after_call(frame) */
 195
 196
 197 /* Address of end of stack space.  */
 198
 199 #define STACK_END_ADDR 0x2ff80000
 200
 201 /* Stack grows downward.  */
 202
 203 #define INNER_THAN <
 204
 205 #if 0
 206 /* No, we shouldn't use this. push_arguments() should leave stack in a
 207    proper alignment! */
 208 /* Stack has strict alignment. */
 209
 210 #define STACK_ALIGN(ADDR)       (((ADDR)+7)&-8)
 211 #endif
 212
 213 /* This is how argumets pushed onto stack or passed in registers. */
 214
 215 #define PUSH_ARGUMENTS(nargs, args, sp, struct_return, struct_addr) \
 216   sp = push_arguments(nargs, args, sp, struct_return, struct_addr)
 217
 218 /* Sequence of bytes for breakpoint instruction.  */
 219
 220 #define BREAKPOINT {0x7d, 0x82, 0x10, 0x08}
 221
 222 /* Amount PC must be decremented by after a breakpoint.
 223    This is often the number of bytes in BREAKPOINT
 224    but not always.  */
 225
 226 #define DECR_PC_AFTER_BREAK 0
 227
 228 /* Nonzero if instruction at PC is a return instruction.  */
 229 /* Allow any of the return instructions, including a trapv and a return
 230    from interrupt.  */
 231
 232 #define ABOUT_TO_RETURN(pc)  \
 233    ((read_memory_integer (pc, 4) & 0xfe8007ff) == 0x4e800020)
 234
 235 /* Return 1 if P points to an invalid floating point value.  */
 236
 237 #define INVALID_FLOAT(p, len) 0   /* Just a first guess; not checked */
 238
 239 /* Largest integer type */
 240
 241 #define LONGEST long
 242
 243 /* Name of the builtin type for the LONGEST type above. */
 244
 245 #define BUILTIN_TYPE_LONGEST builtin_type_long
 246
 247 /* Say how long (ordinary) registers are.  */
 248
 249 #define REGISTER_TYPE long
 250
 251 /* Number of machine registers */
 252
 253 #define NUM_REGS 71
 254
 255 /* Initializer for an array of names of registers.
 256    There should be NUM_REGS strings in this initializer.  */
 257
 258 #define REGISTER_NAMES  \
 259  {"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",  \
 260   "r8", "r9", "r10","r11","r12","r13","r14","r15", \
 261   "r16","r17","r18","r19","r20","r21","r22","r23", \
 262   "r24","r25","r26","r27","r28","r29","r30","r31", \
 263   "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",  \
 264   "f8", "f9", "f10","f11","f12","f13","f14","f15", \
 265   "f16","f17","f18","f19","f20","f21","f22","f23", \
 266   "f24","f25","f26","f27","f28","f29","f30","f31", \
 267   "pc", "ps", "cnd", "lr", "cnt", "xer", "mq" }
 268
 269 /* Register numbers of various important registers.
 270    Note that some of these values are "real" register numbers,
 271    and correspond to the general registers of the machine,
 272    and some are "phony" register numbers which are too large
 273    to be actual register numbers as far as the user is concerned
 274    but do serve to get the desired values when passed to read_register.  */
 275
 276 #define FP_REGNUM 1             /* Contains address of executing stack frame */
 277 #define SP_REGNUM 1             /* Contains address of top of stack */
 278 #define TOC_REGNUM 2            /* TOC register */
 279 #define FP0_REGNUM 32           /* Floating point register 0 */
 280 #define GP0_REGNUM 0            /* GPR register 0 */
 281 #define FP0_REGNUM 32           /* FPR (Floating point) register 0 */
 282 #define FPLAST_REGNUM 63        /* Last floating point register */
 283
 284 /* Special purpose registers... */
 285 /* P.S. keep these in the same order as in /usr/mstsave.h `mstsave' structure, for
 286    easier processing */
 287
 288 #define PC_REGNUM 64            /* Program counter (instruction address %iar) */
 289 #define PS_REGNUM 65            /* Processor (or machine) status (%msr) */
 290 #define CR_REGNUM 66            /* Condition register */
 291 #define LR_REGNUM 67            /* Link register */
 292 #define CTR_REGNUM 68           /* Count register */
 293 #define XER_REGNUM 69           /* Fixed point exception registers */
 294 #define MQ_REGNUM 70            /* Multiply/quotient register */
 295
 296 #define FIRST_SP_REGNUM 64      /* first special register number */
 297 #define LAST_SP_REGNUM  70      /* last special register number */
 298
 299 /* Total amount of space needed to store our copies of the machine's
 300    register state, the array `registers'.
 301
 302         32 4-byte gpr's
 303         32 8-byte fpr's
 304         7  4-byte special purpose registers,
 305
 306    total 416 bytes. Keep some extra space for now, in case to add more. */
 307
 308 #define REGISTER_BYTES 420
 309
 310
 311 /* Index within `registers' of the first byte of the space for
 312    register N.  */
 313
 314 #define REGISTER_BYTE(N)  \
 315  (                                                              \
 316   ((N) > FPLAST_REGNUM) ? ((((N) - FPLAST_REGNUM -1) * 4) + 384)\
 317   :((N) >= FP0_REGNUM) ? ((((N) - FP0_REGNUM) * 8) + 128)       \
 318   :((N) * 4) )
 319
 320 /* Number of bytes of storage in the actual machine representation
 321    for register N. */
 322 /* Note that the unsigned cast here forces the result of the
 323    subtractiion to very high positive values if N < FP0_REGNUM */
 324
 325 #define REGISTER_RAW_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 32 ? 8 : 4)
 326
 327 /* Number of bytes of storage in the program's representation
 328    for register N.  On the RS6000, all regs are 4 bytes
 329    except the floating point regs which are 8-byte doubles.  */
 330
 331 #define REGISTER_VIRTUAL_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 32 ? 8 : 4)
 332
 333 /* Largest value REGISTER_RAW_SIZE can have.  */
 334
 335 #define MAX_REGISTER_RAW_SIZE 8
 336
 337 /* Largest value REGISTER_VIRTUAL_SIZE can have.  */
 338
 339 #define MAX_REGISTER_VIRTUAL_SIZE 8
 340
 341 /* convert a dbx stab register number (from `r' declaration) to a gdb REGNUM */
 342
 343 #define STAB_REG_TO_REGNUM(value)       (value)
 344
 345 /* Nonzero if register N requires conversion
 346    from raw format to virtual format.  */
 347
 348 #define REGISTER_CONVERTIBLE(N) ((N) >= FP0_REGNUM && (N) <= FPLAST_REGNUM)
 349
 350 /* Convert data from raw format for register REGNUM
 351    to virtual format for register REGNUM.  */
 352
 353 #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO)     \
 354    bcopy ((FROM), (TO), REGISTER_RAW_SIZE (REGNUM))
 355
 356 /* Convert data from virtual format for register REGNUM
 357    to raw format for register REGNUM.  */
 358
 359 #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO) \
 360    bcopy ((FROM), (TO), REGISTER_RAW_SIZE (REGNUM))
 361
 362 /* Return the GDB type object for the "standard" data type
 363    of data in register N.  */
 364
 365 #define REGISTER_VIRTUAL_TYPE(N) \
 366  (((unsigned)(N) - FP0_REGNUM) < 32 ? builtin_type_double : builtin_type_int)
 367
 368 /* Store the address of the place in which to copy the structure the
 369    subroutine will return.  This is called from call_function. */
 370 /* in RS6000, struct return addresses are passed as an extra parameter in r3.
 371    In function return, callee is not responsible of returning this address back.
 372    Since gdb needs to find it, we will store in a designated variable
 373    `rs6000_struct_return_address'. */
 374
 375 extern unsigned int rs6000_struct_return_address;
 376
 377 #define STORE_STRUCT_RETURN(ADDR, SP)   \
 378   { write_register (3, (ADDR));         \
 379     rs6000_struct_return_address = (unsigned int)(ADDR); }
 380
 381 /* Extract from an array REGBUF containing the (raw) register state
 382    a function return value of type TYPE, and copy that, in virtual format,
 383    into VALBUF.  */
 384
 385 /* #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
 386   bcopy (REGBUF, VALBUF, TYPE_LENGTH (TYPE)) */
 387
 388 #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
 389   extract_return_value(TYPE,REGBUF,VALBUF)
 390
 391 /* Write into appropriate registers a function return value
 392    of type TYPE, given in virtual format.  */
 393
 394 #define STORE_RETURN_VALUE(TYPE,VALBUF) \
 395   {                                                                     \
 396     if (TYPE_CODE (TYPE) == TYPE_CODE_FLT)                              \
 397                                                                         \
 398      /* Floating point values are returned starting from FPR1 and up.   \
 399         Say a double_double_double type could be returned in            \
 400         FPR1/FPR2/FPR3 triple. */                                       \
 401                                                                         \
 402       write_register_bytes (REGISTER_BYTE (FP0_REGNUM+1), (VALBUF),     \
 403                                                 TYPE_LENGTH (TYPE));    \
 404     else                                                                \
 405       /* Everything else is returned in GPR3 and up. */                 \
 406       write_register_bytes (REGISTER_BYTE (GP0_REGNUM+3), (VALBUF),     \
 407                                                 TYPE_LENGTH (TYPE));    \
 408   }
 409
 410
 411 /* Extract from an array REGBUF containing the (raw) register state
 412    the address in which a function should return its structure value,
 413    as a CORE_ADDR (or an expression that can be used as one).  */
 414
 415 #define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF)    rs6000_struct_return_address
 416 \f
 417 /* Describe the pointer in each stack frame to the previous stack frame
 418    (its caller).  */
 419
 420 /* FRAME_CHAIN takes a frame's nominal address
 421    and produces the frame's chain-pointer. */
 422
 423 /* In the case of the RS6000, the frame's nominal address
 424    is the address of a 4-byte word containing the calling frame's address.  */
 425
 426 #define FRAME_CHAIN(thisframe)  \
 427   (!inside_entry_file ((thisframe)->pc) ?       \
 428    read_memory_integer ((thisframe)->frame, 4) :\
 429    0)
 430
 431 /* Define other aspects of the stack frame.  */
 432
 433 /* A macro that tells us whether the function invocation represented
 434    by FI does not have a frame on the stack associated with it.  If it
 435    does not, FRAMELESS is set to 1, else 0.  */
 436
 437 #define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) \
 438         FRAMELESS = frameless_function_invocation (FI)
 439
 440 /* Functions calling alloca() change the value of the stack pointer. We
 441    need to use initial stack pointer (which is saved in r31 by gcc) in
 442    such cases. If a compiler emits traceback table, then we should use the
 443    alloca register specified in traceback table. FIXME. */
 444 /* Also, it is a good idea to cache information about frame's saved registers
 445    in the frame structure to speed things up. See tm-m88k.h. FIXME. */
 446
 447 #define EXTRA_FRAME_INFO        \
 448         CORE_ADDR initial_sp;                   /* initial stack pointer. */ \
 449         struct frame_saved_regs *cache_fsr;     /* saved registers        */
 450
 451 /* Frameless function invocation in IBM RS/6000 is half-done. It perfectly
 452    sets up a new frame, e.g. a new frame (in fact stack) pointer, etc, but it
 453    doesn't save the %pc. In the following, even though it is considered a
 454    frameless invocation, we still need to walk one frame up. */
 455
 456 #define INIT_EXTRA_FRAME_INFO(fromleaf, fi)     \
 457         fi->initial_sp = 0;             \
 458         fi->cache_fsr = 0;
 459
 460 #define FRAME_SAVED_PC(FRAME)           \
 461         read_memory_integer (read_memory_integer ((FRAME)->frame, 4)+8, 4)
 462
 463 #define FRAME_ARGS_ADDRESS(FI)  \
 464   (((struct frame_info*)(FI))->initial_sp ?             \
 465         ((struct frame_info*)(FI))->initial_sp :        \
 466         frame_initial_stack_address (FI))
 467
 468 #define FRAME_LOCALS_ADDRESS(FI)        FRAME_ARGS_ADDRESS(FI)
 469
 470
 471 /* Set VAL to the number of args passed to frame described by FI.
 472    Can set VAL to -1, meaning no way to tell.  */
 473
 474 /* We can't tell how many args there are
 475    now that the C compiler delays popping them.  */
 476
 477 #define FRAME_NUM_ARGS(val,fi) (val = -1)
 478
 479 /* Return number of bytes at start of arglist that are not really args.  */
 480
 481 #define FRAME_ARGS_SKIP 8       /* Not sure on this. FIXMEmgo */
 482
 483 /* Put here the code to store, into a struct frame_saved_regs,
 484    the addresses of the saved registers of frame described by FRAME_INFO.
 485    This includes special registers such as pc and fp saved in special
 486    ways in the stack frame.  sp is even more special:
 487    the address we return for it IS the sp for the next frame.  */
 488 /* In the following implementation for RS6000, we did *not* save sp. I am
 489    not sure if it will be needed. The following macro takes care of gpr's
 490    and fpr's only. */
 491
 492 #define FRAME_FIND_SAVED_REGS(FRAME_INFO, FRAME_SAVED_REGS)             \
 493 {                                                                       \
 494   int ii, frame_addr, func_start;                                       \
 495   struct aix_framedata fdata;                                                   \
 496                                                                                 \
 497   /* find the start of the function and collect info about its frame. */        \
 498                                                                                 \
 499   func_start = get_pc_function_start ((FRAME_INFO)->pc) + FUNCTION_START_OFFSET;\
 500   function_frame_info (func_start, &fdata);                                     \
 501   bzero (&(FRAME_SAVED_REGS), sizeof (FRAME_SAVED_REGS));                       \
 502                                                                                 \
 503   /* if there were any saved registers, figure out parent's stack pointer. */   \
 504   frame_addr = 0;                                                               \
 505   /* the following is true only if the frame doesn't have a call to alloca(),   \
 506       FIXME. */                                                                 \
 507   if (fdata.saved_fpr >= 0 || fdata.saved_gpr >= 0) {                           \
 508     if ((FRAME_INFO)->prev && (FRAME_INFO)->prev->frame)                        \
 509       frame_addr = (FRAME_INFO)->prev->frame;                                   \
 510     else                                                                        \
 511       frame_addr = read_memory_integer ((FRAME_INFO)->frame, 4);                \
 512   }                                                                             \
 513                                                                                 \
 514   /* if != -1, fdata.saved_fpr is the smallest number of saved_fpr. All fpr's   \
 515      from saved_fpr to fp31 are saved right underneath caller stack pointer,    \
 516      starting from fp31 first. */                                               \
 517                                                                                 \
 518   if (fdata.saved_fpr >= 0) {                                                   \
 519     for (ii=31; ii >= fdata.saved_fpr; --ii)                                    \
 520       (FRAME_SAVED_REGS).regs [FP0_REGNUM + ii] = frame_addr - ((32 - ii) * 8); \
 521     frame_addr -= (32 - fdata.saved_fpr) * 8;                                   \
 522   }                                                                             \
 523                                                                                 \
 524   /* if != -1, fdata.saved_gpr is the smallest number of saved_gpr. All gpr's   \
 525      from saved_gpr to gpr31 are saved right under saved fprs, starting         \
 526      from r31 first. */                                                         \
 527                                                                                 \
 528   if (fdata.saved_gpr >= 0)                                                     \
 529     for (ii=31; ii >= fdata.saved_gpr; --ii)                                    \
 530       (FRAME_SAVED_REGS).regs [ii] = frame_addr - ((32 - ii) * 4);              \
 531 }
 532
 533 \f
 534 /* Things needed for making the inferior call functions.  */
 535
 536 /* Push an empty stack frame, to record the current PC, etc.  */
 537 /* Change these names into rs6k_{push, pop}_frame(). FIXMEmgo. */
 538
 539 #define PUSH_DUMMY_FRAME        push_dummy_frame ()
 540
 541 /* Discard from the stack the innermost frame,
 542    restoring all saved registers.  */
 543
 544 #define POP_FRAME       pop_frame ()
 545
 546 /* This sequence of words is the instructions:
 547
 548         mflr    r0              // 0x7c0802a6
 549                                 // save fpr's
 550         stfd    r?, num(r1)     // 0xd8010000 there should be 32 of this??
 551                                 // save gpr's
 552         stm     r0, num(r1)     // 0xbc010000
 553         stu     r1, num(r1)     // 0x94210000
 554
 555         // the function we want to branch might be in a different load
 556         // segment. reset the toc register. Note that the actual toc address
 557         // will be fix by fix_call_dummy () along with function address.
 558
 559         st      r2, 0x14(r1)    // 0x90410014 save toc register
 560         liu     r2, 0x1234      // 0x3c401234 reset a new toc value 0x12345678
 561         oril    r2, r2,0x5678   // 0x60425678
 562
 563                                 // load absolute address 0x12345678 to r0
 564         liu     r0, 0x1234      // 0x3c001234
 565         oril    r0, r0,0x5678   // 0x60005678
 566         mtctr   r0              // 0x7c0903a6 ctr <- r0
 567         bctrl                   // 0x4e800421 jump subroutine 0x12345678 (%ctr)
 568         cror    0xf, 0xf, 0xf   // 0x4def7b82
 569         brpt                    // 0x7d821008, breakpoint
 570         cror    0xf, 0xf, 0xf   // 0x4def7b82 (for 8 byte alignment)
 571
 572
 573   We actually start executing by saving the toc register first, since the pushing
 574   of the registers is done by PUSH_DUMMY_FRAME.  If this were real code,
 575   the arguments for the function called by the `bctrl' would be pushed
 576   between the `stu' and the `bctrl', and we could allow it to execute through.
 577   But the arguments have to be pushed by GDB after the PUSH_DUMMY_FRAME is done,
 578   and we cannot allow to push the registers again.
 579 */
 580
 581 #define CALL_DUMMY {0x7c0802a6, 0xd8010000, 0xbc010000, 0x94210000, \
 582                     0x90410014, 0x3c401234, 0x60425678,             \
 583                     0x3c001234, 0x60005678, 0x7c0903a6, 0x4e800421, \
 584                     0x4def7b82, 0x7d821008, 0x4def7b82 }
 585
 586
 587 /* keep this as multiple of 8 (%sp requires 8 byte alignment) */
 588 #define CALL_DUMMY_LENGTH 56
 589
 590 #define CALL_DUMMY_START_OFFSET 16
 591
 592 /* Insert the specified number of args and function address
 593    into a call sequence of the above form stored at DUMMYNAME.  */
 594
 595 #define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, using_gcc) \
 596         fix_call_dummy(dummyname, pc, fun, nargs, type)
 597
 598
 599 /* Signal handler for SIGWINCH `window size changed'. */
 600
 601 #define SIGWINCH_HANDLER  aix_resizewindow
 602 extern  void    aix_resizewindow ();
 603
 604 /* `lines_per_page' and `chars_per_line' are local to utils.c. Rectify this. */
 605
 606 #define SIGWINCH_HANDLER_BODY   \
 607                                                                         \
 608 /* Respond to SIGWINCH `window size changed' signal, and reset GDB's    \
 609    window settings approproatelt. */                                    \
 610                                                                         \
 611 void                                            \
 612 aix_resizewindow ()                             \
 613 {                                               \
 614   int fd = fileno (stdout);                     \
 615   if (isatty (fd)) {                            \
 616     int val;                                    \
 617                                                 \
 618     val = atoi (termdef (fd, 'l'));             \
 619     if (val > 0)                                \
 620       lines_per_page = val;                     \
 621     val = atoi (termdef (fd, 'c'));             \
 622     if (val > 0)                                \
 623       chars_per_line = val;                     \
 624   }                                             \
 625 }
 626
 627
 628 /* Flag for machine-specific stuff in shared files.  FIXME */
 629 #define IBM6000_TARGET
 630
 631 /* RS6000/AIX does not support PT_STEP.  Has to be simulated.  */
 632
 633 #define NO_SINGLE_STEP