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, (int *)1, signal, 0); \
  29   if (errno) { \
  30 /*    printf ("ret: %d, errno: %d, signal: %d\n", ret, errno, signal); */ \
  31     errno = 0; } \
  32 }
  33
  34 extern int      symtab_relocated;
  35
  36 /* Minimum possible text address in AIX */
  37
  38 #define TEXT_SEGMENT_BASE       0x10000000
  39
  40
  41 /* text addresses in a core file does not necessarily match to symbol table,
  42    if symbol table relocation wasn't done yet. */
  43
  44 #define CORE_NEEDS_RELOCATION(PC)       \
  45   if (!symtab_relocated && !inferior_pid && (PC) >  TEXT_SEGMENT_BASE)  \
  46     (PC) -= ( TEXT_SEGMENT_BASE + text_adjustment (exec_bfd));
  47
  48 /* Load segment of a given pc value. */
  49
  50 #define PC_LOAD_SEGMENT(PC)     pc_load_segment_name(PC)
  51
  52
  53 /* Conversion between a register number in stab string to actual register num. */
  54
  55 #define STAB_REG_TO_REGNUM(value)       (value)
  56
  57 /* return true if a given `pc' value is in `call dummy' function. */
  58
  59 #define PC_IN_CALL_DUMMY(STOP_PC, STOP_SP, STOP_FRAME_ADDR)     \
  60         (STOP_SP < STOP_PC && STOP_PC < STACK_END_ADDR)
  61
  62 /* For each symtab, we keep track of which BFD it came from.  */
  63 #define EXTRA_SYMTAB_INFO       \
  64         unsigned    nonreloc:1;         /* TRUE if non relocatable */
  65
  66 #define INIT_EXTRA_SYMTAB_INFO(symtab)  \
  67         symtab->nonreloc = 0;           \
  68
  69 extern unsigned int text_start, data_start;
  70 extern int inferior_pid;
  71 extern char *corefile;
  72
  73 /* setpgrp() messes up controling terminal. The other version of it
  74    requires libbsd.a. */
  75 #define setpgrp(XX,YY)          setpgid (XX, YY)
  76
  77 /* We are missing register descriptions in the system header files. Sigh! */
  78
  79 struct regs {
  80         int     gregs [32];             /* general purpose registers */
  81         int     pc;                     /* program conter       */
  82         int     ps;                     /* processor status, or machine state */
  83 };
  84
  85 struct fp_status {
  86         double  fpregs [32];            /* floating GP registers */
  87 };
  88
  89
  90 /* To be used by function_frame_info. */
  91
  92 struct aix_framedata {
  93   int   offset;                         /* # of bytes in gpr's and fpr's are saved */
  94   int   saved_gpr;                      /* smallest # of saved gpr */
  95   int   saved_fpr;                      /* smallest # of saved fpr */
  96   int   alloca_reg;                     /* alloca register number (frame ptr) */
  97   char  frameless;                      /* true if frameless functions. */
  98 };
  99
 100
 101 /* Define the byte order of the machine.  */
 102
 103 #define TARGET_BYTE_ORDER       BIG_ENDIAN
 104
 105 /* Define this if the C compiler puts an underscore at the front
 106    of external names before giving them to the linker.  */
 107
 108 #undef NAMES_HAVE_UNDERSCORE
 109
 110 /* AIX's assembler doesn't grok dollar signs in identifiers.
 111    So we use dots instead.  This item must be coordinated with G++. */
 112 #undef CPLUS_MARKER
 113 #define CPLUS_MARKER '.'
 114
 115 /* Offset from address of function to start of its code.
 116    Zero on most machines.  */
 117
 118 #define FUNCTION_START_OFFSET 0
 119
 120 /* Advance PC across any function entry prologue instructions
 121    to reach some "real" code.  */
 122
 123 #define SKIP_PROLOGUE(pc)       pc = skip_prologue (pc)
 124
 125 /* If PC is in some function-call trampoline code, return the PC
 126    where the function itself actually starts.  If not, return NULL.  */
 127
 128 #define SKIP_TRAMPOLINE_CODE(pc)        skip_trampoline_code (pc)
 129
 130 /* When a child process is just starting, we sneak in and relocate
 131    the symbol table (and other stuff) after the dynamic linker has
 132    figured out where they go. But we want to do this relocation just
 133    once. */
 134
 135 extern int aix_loadInfoTextIndex;
 136
 137 #define SOLIB_CREATE_INFERIOR_HOOK(PID) \
 138   do {                                  \
 139     if (aix_loadInfoTextIndex == 0)     \
 140         aixcoff_relocate_symtab (PID);  \
 141   } while (0)
 142
 143
 144 /* Number of trap signals we need to skip over, once the inferior process
 145    starts running. */
 146
 147 #define START_INFERIOR_TRAPS_EXPECTED   2
 148
 149 /* AIX might return a sigtrap, with a "stop after load" status. It should
 150    be ignored by gdb, shouldn't be mixed up with breakpoint traps. */
 151
 152 /* Another little glitch  in AIX is signal 0. I have no idea why wait(2)
 153    returns with this status word. It looks harmless. */
 154
 155 #define SIGTRAP_STOP_AFTER_LOAD(W)      \
 156  if ( (W) == 0x57c || (W) == 0x7f) {    \
 157    if ((W)==0x57c && breakpoints_inserted) {    \
 158      mark_breakpoints_out ();           \
 159      insert_breakpoints ();             \
 160      insert_step_breakpoint ();         \
 161    }                                    \
 162    resume (0, 0);                       \
 163    continue;                            \
 164  }
 165
 166 /* In aixcoff, we cannot process line numbers when we see them. This is
 167    mainly because we don't know the boundaries of the include files. So,
 168    we postpone that, and then enter and sort(?) the whole line table at
 169    once, when we are closing the current symbol table in end_symtab(). */
 170
 171 #define PROCESS_LINENUMBER_HOOK()       aix_process_linenos ()
 172
 173
 174 /* When a target process or core-file has been attached, we sneak in
 175    and figure out where the shared libraries have got to. In case there
 176    is no inferior_process exists (e.g. bringing up a core file), we can't
 177    attemtp to relocate symbol table, since we don't have information about
 178    load segments. */
 179
 180 #define SOLIB_ADD(a, b, c)      \
 181    if (inferior_pid)    aixcoff_relocate_symtab (inferior_pid)
 182
 183 /* Immediately after a function call, return the saved pc.
 184    Can't go through the frames for this because on some machines
 185    the new frame is not set up until the new function executes
 186    some instructions.  */
 187
 188 extern char registers[];
 189 extern char register_valid [];
 190
 191 #define SAVED_PC_AFTER_CALL(frame)      \
 192         (register_valid [LR_REGNUM] ?   \
 193           (*(int*)&registers[REGISTER_BYTE (LR_REGNUM)]) :      \
 194           read_register (LR_REGNUM))
 195
 196 /*#define SAVED_PC_AFTER_CALL(frame)    saved_pc_after_call(frame) */
 197
 198
 199 /* Address of end of stack space.  */
 200
 201 #define STACK_END_ADDR 0x2ff80000
 202
 203 /* Stack grows downward.  */
 204
 205 #define INNER_THAN <
 206
 207 #if 0
 208 /* No, we shouldn't use this. push_arguments() should leave stack in a
 209    proper alignment! */
 210 /* Stack has strict alignment. */
 211
 212 #define STACK_ALIGN(ADDR)       (((ADDR)+7)&-8)
 213 #endif
 214
 215 /* This is how argumets pushed onto stack or passed in registers. */
 216
 217 #define PUSH_ARGUMENTS(nargs, args, sp, struct_return, struct_addr) \
 218   sp = push_arguments(nargs, args, sp, struct_return, struct_addr)
 219
 220 /* Sequence of bytes for breakpoint instruction.  */
 221
 222 #define BREAKPOINT {0x7d, 0x82, 0x10, 0x08}
 223
 224 /* Amount PC must be decremented by after a breakpoint.
 225    This is often the number of bytes in BREAKPOINT
 226    but not always.  */
 227
 228 #define DECR_PC_AFTER_BREAK 0
 229
 230 /* Nonzero if instruction at PC is a return instruction.  */
 231 /* Allow any of the return instructions, including a trapv and a return
 232    from interrupt.  */
 233
 234 #define ABOUT_TO_RETURN(pc)  \
 235    ((read_memory_integer (pc, 4) & 0xfe8007ff) == 0x4e800020)
 236
 237 /* Return 1 if P points to an invalid floating point value.  */
 238
 239 #define INVALID_FLOAT(p, len) 0   /* Just a first guess; not checked */
 240
 241 /* Largest integer type */
 242
 243 #define LONGEST long
 244
 245 /* Name of the builtin type for the LONGEST type above. */
 246
 247 #define BUILTIN_TYPE_LONGEST builtin_type_long
 248
 249 /* Say how long (ordinary) registers are.  */
 250
 251 #define REGISTER_TYPE long
 252
 253 /* Number of machine registers */
 254
 255 #define NUM_REGS 71
 256
 257 /* Initializer for an array of names of registers.
 258    There should be NUM_REGS strings in this initializer.  */
 259
 260 #define REGISTER_NAMES  \
 261  {"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",  \
 262   "r8", "r9", "r10","r11","r12","r13","r14","r15", \
 263   "r16","r17","r18","r19","r20","r21","r22","r23", \
 264   "r24","r25","r26","r27","r28","r29","r30","r31", \
 265   "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",  \
 266   "f8", "f9", "f10","f11","f12","f13","f14","f15", \
 267   "f16","f17","f18","f19","f20","f21","f22","f23", \
 268   "f24","f25","f26","f27","f28","f29","f30","f31", \
 269   "pc", "ps", "cnd", "lr", "cnt", "xer", "mq" }
 270
 271 /* Register numbers of various important registers.
 272    Note that some of these values are "real" register numbers,
 273    and correspond to the general registers of the machine,
 274    and some are "phony" register numbers which are too large
 275    to be actual register numbers as far as the user is concerned
 276    but do serve to get the desired values when passed to read_register.  */
 277
 278 #define FP_REGNUM 1             /* Contains address of executing stack frame */
 279 #define SP_REGNUM 1             /* Contains address of top of stack */
 280 #define TOC_REGNUM 2            /* TOC register */
 281 #define FP0_REGNUM 32           /* Floating point register 0 */
 282 #define GP0_REGNUM 0            /* GPR register 0 */
 283 #define FP0_REGNUM 32           /* FPR (Floating point) register 0 */
 284 #define FPLAST_REGNUM 63        /* Last floating point register */
 285
 286 /* Special purpose registers... */
 287 /* P.S. keep these in the same order as in /usr/mstsave.h `mstsave' structure, for
 288    easier processing */
 289
 290 #define PC_REGNUM 64            /* Program counter (instruction address %iar) */
 291 #define PS_REGNUM 65            /* Processor (or machine) status (%msr) */
 292 #define CR_REGNUM 66            /* Condition register */
 293 #define LR_REGNUM 67            /* Link register */
 294 #define CTR_REGNUM 68           /* Count register */
 295 #define XER_REGNUM 69           /* Fixed point exception registers */
 296 #define MQ_REGNUM 70            /* Multiply/quotient register */
 297
 298 #define FIRST_SP_REGNUM 64      /* first special register number */
 299 #define LAST_SP_REGNUM  70      /* last special register number */
 300
 301 /* Total amount of space needed to store our copies of the machine's
 302    register state, the array `registers'.
 303
 304         32 4-byte gpr's
 305         32 8-byte fpr's
 306         7  4-byte special purpose registers,
 307
 308    total 416 bytes. Keep some extra space for now, in case to add more. */
 309
 310 #define REGISTER_BYTES 420
 311
 312
 313 /* Index within `registers' of the first byte of the space for
 314    register N.  */
 315
 316 #define REGISTER_BYTE(N)  \
 317  (                                                              \
 318   ((N) > FPLAST_REGNUM) ? ((((N) - FPLAST_REGNUM -1) * 4) + 384)\
 319   :((N) >= FP0_REGNUM) ? ((((N) - FP0_REGNUM) * 8) + 128)       \
 320   :((N) * 4) )
 321
 322 /* Number of bytes of storage in the actual machine representation
 323    for register N. */
 324 /* Note that the unsigned cast here forces the result of the
 325    subtractiion to very high positive values if N < FP0_REGNUM */
 326
 327 #define REGISTER_RAW_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 32 ? 8 : 4)
 328
 329 /* Number of bytes of storage in the program's representation
 330    for register N.  On the RS6000, all regs are 4 bytes
 331    except the floating point regs which are 8-byte doubles.  */
 332
 333 #define REGISTER_VIRTUAL_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 32 ? 8 : 4)
 334
 335 /* Largest value REGISTER_RAW_SIZE can have.  */
 336
 337 #define MAX_REGISTER_RAW_SIZE 8
 338
 339 /* Largest value REGISTER_VIRTUAL_SIZE can have.  */
 340
 341 #define MAX_REGISTER_VIRTUAL_SIZE 8
 342
 343 /* convert a dbx stab register number (from `r' declaration) to a gdb REGNUM */
 344
 345 #define STAB_REG_TO_REGNUM(value)       (value)
 346
 347 /* Nonzero if register N requires conversion
 348    from raw format to virtual format.  */
 349
 350 #define REGISTER_CONVERTIBLE(N) ((N) >= FP0_REGNUM && (N) <= FPLAST_REGNUM)
 351
 352 /* Convert data from raw format for register REGNUM
 353    to virtual format for register REGNUM.  */
 354
 355 #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO)     \
 356    bcopy ((FROM), (TO), REGISTER_RAW_SIZE (REGNUM))
 357
 358 /* Convert data from virtual format for register REGNUM
 359    to raw format for register REGNUM.  */
 360
 361 #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO) \
 362    bcopy ((FROM), (TO), REGISTER_RAW_SIZE (REGNUM))
 363
 364 /* Return the GDB type object for the "standard" data type
 365    of data in register N.  */
 366
 367 #define REGISTER_VIRTUAL_TYPE(N) \
 368  (((unsigned)(N) - FP0_REGNUM) < 32 ? builtin_type_double : builtin_type_int)
 369
 370 /* Store the address of the place in which to copy the structure the
 371    subroutine will return.  This is called from call_function. */
 372 /* in RS6000, struct return addresses are passed as an extra parameter in r3.
 373    In function return, callee is not responsible of returning this address back.
 374    Since gdb needs to find it, we will store in a designated variable
 375    `rs6000_struct_return_address'. */
 376
 377 extern unsigned int rs6000_struct_return_address;
 378
 379 #define STORE_STRUCT_RETURN(ADDR, SP)   \
 380   { write_register (3, (ADDR));         \
 381     rs6000_struct_return_address = (unsigned int)(ADDR); }
 382
 383 /* Extract from an array REGBUF containing the (raw) register state
 384    a function return value of type TYPE, and copy that, in virtual format,
 385    into VALBUF.  */
 386
 387 /* #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
 388   bcopy (REGBUF, VALBUF, TYPE_LENGTH (TYPE)) */
 389
 390 #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
 391   extract_return_value(TYPE,REGBUF,VALBUF)
 392
 393 /* Write into appropriate registers a function return value
 394    of type TYPE, given in virtual format.  */
 395
 396 #define STORE_RETURN_VALUE(TYPE,VALBUF) \
 397   {                                                                     \
 398     if (TYPE_CODE (TYPE) == TYPE_CODE_FLT)                              \
 399                                                                         \
 400      /* Floating point values are returned starting from FPR1 and up.   \
 401         Say a double_double_double type could be returned in            \
 402         FPR1/FPR2/FPR3 triple. */                                       \
 403                                                                         \
 404       write_register_bytes (REGISTER_BYTE (FP0_REGNUM+1), (VALBUF),     \
 405                                                 TYPE_LENGTH (TYPE));    \
 406     else                                                                \
 407       /* Everything else is returned in GPR3 and up. */                 \
 408       write_register_bytes (REGISTER_BYTE (GP0_REGNUM+3), (VALBUF),     \
 409                                                 TYPE_LENGTH (TYPE));    \
 410   }
 411
 412
 413 /* Extract from an array REGBUF containing the (raw) register state
 414    the address in which a function should return its structure value,
 415    as a CORE_ADDR (or an expression that can be used as one).  */
 416
 417 #define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF)    rs6000_struct_return_address
 418
 419
 420 /* Do implement the attach and detach commands.  */
 421
 422 #define ATTACH_DETACH
 423
 424 /* infptrace.c requires those. */
 425
 426 #define PTRACE_ATTACH 30
 427 #define PTRACE_DETACH 31
 428
 429 \f
 430 /* Describe the pointer in each stack frame to the previous stack frame
 431    (its caller).  */
 432
 433 /* FRAME_CHAIN takes a frame's nominal address
 434    and produces the frame's chain-pointer. */
 435
 436 /* In the case of the RS6000, the frame's nominal address
 437    is the address of a 4-byte word containing the calling frame's address.  */
 438
 439 #define FRAME_CHAIN(thisframe)  \
 440   (!inside_entry_file ((thisframe)->pc) ?       \
 441    read_memory_integer ((thisframe)->frame, 4) :\
 442    0)
 443
 444 /* Define other aspects of the stack frame.  */
 445
 446 /* A macro that tells us whether the function invocation represented
 447    by FI does not have a frame on the stack associated with it.  If it
 448    does not, FRAMELESS is set to 1, else 0.  */
 449
 450 #define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) \
 451         FRAMELESS = frameless_function_invocation (FI)
 452
 453 /* Functions calling alloca() change the value of the stack pointer. We
 454    need to use initial stack pointer (which is saved in r31 by gcc) in
 455    such cases. If a compiler emits traceback table, then we should use the
 456    alloca register specified in traceback table. FIXME. */
 457 /* Also, it is a good idea to cache information about frame's saved registers
 458    in the frame structure to speed things up. See tm-m88k.h. FIXME. */
 459
 460 #define EXTRA_FRAME_INFO        \
 461         CORE_ADDR initial_sp;                   /* initial stack pointer. */ \
 462         struct frame_saved_regs *cache_fsr;     /* saved registers        */
 463
 464 /* Frameless function invocation in IBM RS/6000 is half-done. It perfectly
 465    sets up a new frame, e.g. a new frame (in fact stack) pointer, etc, but it
 466    doesn't save the %pc. In the following, even though it is considered a
 467    frameless invocation, we still need to walk one frame up. */
 468
 469 #define INIT_EXTRA_FRAME_INFO(fromleaf, fi)     \
 470         fi->initial_sp = 0;             \
 471         fi->cache_fsr = 0;
 472
 473 #define FRAME_SAVED_PC(FRAME)           \
 474         read_memory_integer (read_memory_integer ((FRAME)->frame, 4)+8, 4)
 475
 476 #define FRAME_ARGS_ADDRESS(FI)  \
 477   (((struct frame_info*)(FI))->initial_sp ?             \
 478         ((struct frame_info*)(FI))->initial_sp :        \
 479         frame_initial_stack_address (FI))
 480
 481 #define FRAME_LOCALS_ADDRESS(FI)        FRAME_ARGS_ADDRESS(FI)
 482
 483
 484 /* Set VAL to the number of args passed to frame described by FI.
 485    Can set VAL to -1, meaning no way to tell.  */
 486
 487 /* We can't tell how many args there are
 488    now that the C compiler delays popping them.  */
 489
 490 #define FRAME_NUM_ARGS(val,fi) (val = -1)
 491
 492 /* Return number of bytes at start of arglist that are not really args.  */
 493
 494 #define FRAME_ARGS_SKIP 8       /* Not sure on this. FIXMEmgo */
 495
 496 /* Put here the code to store, into a struct frame_saved_regs,
 497    the addresses of the saved registers of frame described by FRAME_INFO.
 498    This includes special registers such as pc and fp saved in special
 499    ways in the stack frame.  sp is even more special:
 500    the address we return for it IS the sp for the next frame.  */
 501 /* In the following implementation for RS6000, we did *not* save sp. I am
 502    not sure if it will be needed. The following macro takes care of gpr's
 503    and fpr's only. */
 504
 505 #define FRAME_FIND_SAVED_REGS(FRAME_INFO, FRAME_SAVED_REGS)             \
 506 {                                                                       \
 507   int ii, frame_addr, func_start;                                       \
 508   struct aix_framedata fdata;                                                   \
 509                                                                                 \
 510   /* find the start of the function and collect info about its frame. */        \
 511                                                                                 \
 512   func_start = get_pc_function_start ((FRAME_INFO)->pc) + FUNCTION_START_OFFSET;\
 513   function_frame_info (func_start, &fdata);                                     \
 514   bzero (&(FRAME_SAVED_REGS), sizeof (FRAME_SAVED_REGS));                       \
 515                                                                                 \
 516   /* if there were any saved registers, figure out parent's stack pointer. */   \
 517   frame_addr = 0;                                                               \
 518   /* the following is true only if the frame doesn't have a call to alloca(),   \
 519       FIXME. */                                                                 \
 520   if (fdata.saved_fpr >= 0 || fdata.saved_gpr >= 0) {                           \
 521     if ((FRAME_INFO)->prev && (FRAME_INFO)->prev->frame)                        \
 522       frame_addr = (FRAME_INFO)->prev->frame;                                   \
 523     else                                                                        \
 524       frame_addr = read_memory_integer ((FRAME_INFO)->frame, 4);                \
 525   }                                                                             \
 526                                                                                 \
 527   /* if != -1, fdata.saved_fpr is the smallest number of saved_fpr. All fpr's   \
 528      from saved_fpr to fp31 are saved right underneath caller stack pointer,    \
 529      starting from fp31 first. */                                               \
 530                                                                                 \
 531   if (fdata.saved_fpr >= 0) {                                                   \
 532     for (ii=31; ii >= fdata.saved_fpr; --ii)                                    \
 533       (FRAME_SAVED_REGS).regs [FP0_REGNUM + ii] = frame_addr - ((32 - ii) * 8); \
 534     frame_addr -= (32 - fdata.saved_fpr) * 8;                                   \
 535   }                                                                             \
 536                                                                                 \
 537   /* if != -1, fdata.saved_gpr is the smallest number of saved_gpr. All gpr's   \
 538      from saved_gpr to gpr31 are saved right under saved fprs, starting         \
 539      from r31 first. */                                                         \
 540                                                                                 \
 541   if (fdata.saved_gpr >= 0)                                                     \
 542     for (ii=31; ii >= fdata.saved_gpr; --ii)                                    \
 543       (FRAME_SAVED_REGS).regs [ii] = frame_addr - ((32 - ii) * 4);              \
 544 }
 545
 546 \f
 547 /* Things needed for making the inferior call functions.  */
 548
 549 /* Push an empty stack frame, to record the current PC, etc.  */
 550 /* Change these names into rs6k_{push, pop}_frame(). FIXMEmgo. */
 551
 552 #define PUSH_DUMMY_FRAME        push_dummy_frame ()
 553
 554 /* Discard from the stack the innermost frame,
 555    restoring all saved registers.  */
 556
 557 #define POP_FRAME       pop_frame ()
 558
 559 /* This sequence of words is the instructions:
 560
 561         mflr    r0              // 0x7c0802a6
 562                                 // save fpr's
 563         stfd    r?, num(r1)     // 0xd8010000 there should be 32 of this??
 564                                 // save gpr's
 565         stm     r0, num(r1)     // 0xbc010000
 566         stu     r1, num(r1)     // 0x94210000
 567
 568         // the function we want to branch might be in a different load
 569         // segment. reset the toc register. Note that the actual toc address
 570         // will be fix by fix_call_dummy () along with function address.
 571
 572         st      r2, 0x14(r1)    // 0x90410014 save toc register
 573         liu     r2, 0x1234      // 0x3c401234 reset a new toc value 0x12345678
 574         oril    r2, r2,0x5678   // 0x60425678
 575
 576                                 // load absolute address 0x12345678 to r0
 577         liu     r0, 0x1234      // 0x3c001234
 578         oril    r0, r0,0x5678   // 0x60005678
 579         mtctr   r0              // 0x7c0903a6 ctr <- r0
 580         bctrl                   // 0x4e800421 jump subroutine 0x12345678 (%ctr)
 581         cror    0xf, 0xf, 0xf   // 0x4def7b82
 582         brpt                    // 0x7d821008, breakpoint
 583         cror    0xf, 0xf, 0xf   // 0x4def7b82 (for 8 byte alignment)
 584
 585
 586   We actually start executing by saving the toc register first, since the pushing
 587   of the registers is done by PUSH_DUMMY_FRAME.  If this were real code,
 588   the arguments for the function called by the `bctrl' would be pushed
 589   between the `stu' and the `bctrl', and we could allow it to execute through.
 590   But the arguments have to be pushed by GDB after the PUSH_DUMMY_FRAME is done,
 591   and we cannot allow to push the registers again.
 592 */
 593
 594 #define CALL_DUMMY {0x7c0802a6, 0xd8010000, 0xbc010000, 0x94210000, \
 595                     0x90410014, 0x3c401234, 0x60425678,             \
 596                     0x3c001234, 0x60005678, 0x7c0903a6, 0x4e800421, \
 597                     0x4def7b82, 0x7d821008, 0x4def7b82 }
 598
 599
 600 /* keep this as multiple of 8 (%sp requires 8 byte alignment) */
 601 #define CALL_DUMMY_LENGTH 56
 602
 603 #define CALL_DUMMY_START_OFFSET 16
 604
 605 /* Insert the specified number of args and function address
 606    into a call sequence of the above form stored at DUMMYNAME.  */
 607
 608 #define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, using_gcc) \
 609         fix_call_dummy(dummyname, pc, fun, nargs, type)
 610
 611
 612 /* Signal handler for SIGWINCH `window size changed'. */
 613
 614 #define SIGWINCH_HANDLER  aix_resizewindow
 615 extern  void    aix_resizewindow ();
 616
 617 /* `lines_per_page' and `chars_per_line' are local to utils.c. Rectify this. */
 618
 619 #define SIGWINCH_HANDLER_BODY   \
 620                                                                         \
 621 /* Respond to SIGWINCH `window size changed' signal, and reset GDB's    \
 622    window settings approproatelt. */                                    \
 623                                                                         \
 624 void                                            \
 625 aix_resizewindow ()                             \
 626 {                                               \
 627   int fd = fileno (stdout);                     \
 628   if (isatty (fd)) {                            \
 629     int val;                                    \
 630                                                 \
 631     val = atoi (termdef (fd, 'l'));             \
 632     if (val > 0)                                \
 633       lines_per_page = val;                     \
 634     val = atoi (termdef (fd, 'c'));             \
 635     if (val > 0)                                \
 636       chars_per_line = val;                     \
 637   }                                             \
 638 }
 639
 640
 641 /* Flag for machine-specific stuff in shared files.  FIXME */
 642 #define IBM6000_TARGET