gdb/h8300-tdep.c

   1 /* Target-machine dependent code for Hitachi H8/300, for GDB.
   2    Copyright (C) 1988, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 /*
  21  Contributed by Steve Chamberlain
  22                 sac@cygnus.com
  23  */
  24
  25 #include "defs.h"
  26 #include "frame.h"
  27 #include "obstack.h"
  28 #include "symtab.h"
  29 #include "dis-asm.h"
  30 #include "gdbcmd.h"
  31 #include "gdbtypes.h"
  32 #include "gdbcore.h"
  33 #include "gdb_string.h"
  34 #include "value.h"
  35
  36
  37 #undef NUM_REGS
  38 #define NUM_REGS 11
  39
  40 #define UNSIGNED_SHORT(X) ((X) & 0xffff)
  41
  42 /* an easy to debug H8 stack frame looks like:
  43 0x6df6          push    r6
  44 0x0d76          mov.w   r7,r6
  45 0x6dfn          push    reg
  46 0x7905 nnnn     mov.w  #n,r5    or   0x1b87  subs #2,sp
  47 0x1957          sub.w  r5,sp
  48
  49  */
  50
  51 #define IS_PUSH(x) ((x & 0xff00)==0x6d00)
  52 #define IS_PUSH_FP(x) (x == 0x6df6)
  53 #define IS_MOVE_FP(x) (x == 0x0d76)
  54 #define IS_MOV_SP_FP(x) (x == 0x0d76)
  55 #define IS_SUB2_SP(x) (x==0x1b87)
  56 #define IS_MOVK_R5(x) (x==0x7905)
  57 #define IS_SUB_R5SP(x) (x==0x1957)
  58
  59 /* Local function declarations.  */
  60
  61 static CORE_ADDR examine_prologue ();
  62 static void set_machine_hook PARAMS ((char *filename));
  63
  64 void frame_find_saved_regs ();
  65 CORE_ADDR
  66 h8300_skip_prologue (start_pc)
  67      CORE_ADDR start_pc;
  68 {
  69   short int w;
  70
  71   w = read_memory_unsigned_integer (start_pc, 2);
  72   /* Skip past all push insns */
  73   while (IS_PUSH_FP (w))
  74     {
  75       start_pc += 2;
  76       w = read_memory_unsigned_integer (start_pc, 2);
  77     }
  78
  79   /* Skip past a move to FP */
  80   if (IS_MOVE_FP (w))
  81     {
  82       start_pc += 2;
  83       w = read_memory_unsigned_integer (start_pc, 2);
  84     }
  85
  86   /* Skip the stack adjust */
  87
  88   if (IS_MOVK_R5 (w))
  89     {
  90       start_pc += 2;
  91       w = read_memory_unsigned_integer (start_pc, 2);
  92     }
  93   if (IS_SUB_R5SP (w))
  94     {
  95       start_pc += 2;
  96       w = read_memory_unsigned_integer (start_pc, 2);
  97     }
  98   while (IS_SUB2_SP (w))
  99     {
 100       start_pc += 2;
 101       w = read_memory_unsigned_integer (start_pc, 2);
 102     }
 103
 104   return start_pc;
 105 }
 106
 107 int
 108 gdb_print_insn_h8300 (memaddr, info)
 109      bfd_vma memaddr;
 110      disassemble_info *info;
 111 {
 112   if (h8300hmode)
 113     return print_insn_h8300h (memaddr, info);
 114   else
 115     return print_insn_h8300 (memaddr, info);
 116 }
 117
 118 /* Given a GDB frame, determine the address of the calling function's frame.
 119    This will be used to create a new GDB frame struct, and then
 120    INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame.
 121
 122    For us, the frame address is its stack pointer value, so we look up
 123    the function prologue to determine the caller's sp value, and return it.  */
 124
 125 CORE_ADDR
 126 h8300_frame_chain (thisframe)
 127      struct frame_info *thisframe;
 128 {
 129   frame_find_saved_regs (thisframe, (struct frame_saved_regs *) 0);
 130   return thisframe->fsr->regs[SP_REGNUM];
 131 }
 132
 133 /* Put here the code to store, into a struct frame_saved_regs,
 134    the addresses of the saved registers of frame described by FRAME_INFO.
 135    This includes special registers such as pc and fp saved in special
 136    ways in the stack frame.  sp is even more special:
 137    the address we return for it IS the sp for the next frame.
 138
 139    We cache the result of doing this in the frame_cache_obstack, since
 140    it is fairly expensive.  */
 141
 142 void
 143 frame_find_saved_regs (fi, fsr)
 144      struct frame_info *fi;
 145      struct frame_saved_regs *fsr;
 146 {
 147   register struct frame_saved_regs *cache_fsr;
 148   extern struct obstack frame_cache_obstack;
 149   CORE_ADDR ip;
 150   struct symtab_and_line sal;
 151   CORE_ADDR limit;
 152
 153   if (!fi->fsr)
 154     {
 155       cache_fsr = (struct frame_saved_regs *)
 156         obstack_alloc (&frame_cache_obstack,
 157                        sizeof (struct frame_saved_regs));
 158       memset (cache_fsr, '\0', sizeof (struct frame_saved_regs));
 159
 160       fi->fsr = cache_fsr;
 161
 162       /* Find the start and end of the function prologue.  If the PC
 163          is in the function prologue, we only consider the part that
 164          has executed already.  */
 165
 166       ip = get_pc_function_start (fi->pc);
 167       sal = find_pc_line (ip, 0);
 168       limit = (sal.end && sal.end < fi->pc) ? sal.end : fi->pc;
 169
 170       /* This will fill in fields in *fi as well as in cache_fsr.  */
 171       examine_prologue (ip, limit, fi->frame, cache_fsr, fi);
 172     }
 173
 174   if (fsr)
 175     *fsr = *fi->fsr;
 176 }
 177
 178 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 179    is not the address of a valid instruction, the address of the next
 180    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 181    of the instruction.*/
 182
 183 CORE_ADDR
 184 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 185      CORE_ADDR addr;
 186      CORE_ADDR lim;
 187      INSN_WORD *pword1;
 188 {
 189   char buf[2];
 190   if (addr < lim + 8)
 191     {
 192       read_memory (addr, buf, 2);
 193       *pword1 = extract_signed_integer (buf, 2);
 194
 195       return addr + 2;
 196     }
 197   return 0;
 198 }
 199
 200 /* Examine the prologue of a function.  `ip' points to the first instruction.
 201    `limit' is the limit of the prologue (e.g. the addr of the first
 202    linenumber, or perhaps the program counter if we're stepping through).
 203    `frame_sp' is the stack pointer value in use in this frame.
 204    `fsr' is a pointer to a frame_saved_regs structure into which we put
 205    info about the registers saved by this frame.
 206    `fi' is a struct frame_info pointer; we fill in various fields in it
 207    to reflect the offsets of the arg pointer and the locals pointer.  */
 208
 209 static CORE_ADDR
 210 examine_prologue (ip, limit, after_prolog_fp, fsr, fi)
 211      register CORE_ADDR ip;
 212      register CORE_ADDR limit;
 213      CORE_ADDR after_prolog_fp;
 214      struct frame_saved_regs *fsr;
 215      struct frame_info *fi;
 216 {
 217   register CORE_ADDR next_ip;
 218   int r;
 219   int have_fp = 0;
 220   INSN_WORD insn_word;
 221   /* Number of things pushed onto stack, starts at 2/4, 'cause the
 222      PC is already there */
 223   unsigned int reg_save_depth = h8300hmode ? 4 : 2;
 224
 225   unsigned int auto_depth = 0;  /* Number of bytes of autos */
 226
 227   char in_frame[11];            /* One for each reg */
 228
 229   memset (in_frame, 1, 11);
 230   for (r = 0; r < 8; r++)
 231     {
 232       fsr->regs[r] = 0;
 233     }
 234   if (after_prolog_fp == 0)
 235     {
 236       after_prolog_fp = read_register (SP_REGNUM);
 237     }
 238   if (ip == 0 || ip & (h8300hmode ? ~0xffff : ~0xffff))
 239     return 0;
 240
 241   next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 242
 243   /* Skip over any fp push instructions */
 244   fsr->regs[6] = after_prolog_fp;
 245   while (next_ip && IS_PUSH_FP (insn_word))
 246     {
 247       ip = next_ip;
 248
 249       in_frame[insn_word & 0x7] = reg_save_depth;
 250       next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 251       reg_save_depth += 2;
 252     }
 253
 254   /* Is this a move into the fp */
 255   if (next_ip && IS_MOV_SP_FP (insn_word))
 256     {
 257       ip = next_ip;
 258       next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 259       have_fp = 1;
 260     }
 261
 262   /* Skip over any stack adjustment, happens either with a number of
 263      sub#2,sp or a mov #x,r5 sub r5,sp */
 264
 265   if (next_ip && IS_SUB2_SP (insn_word))
 266     {
 267       while (next_ip && IS_SUB2_SP (insn_word))
 268         {
 269           auto_depth += 2;
 270           ip = next_ip;
 271           next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 272         }
 273     }
 274   else
 275     {
 276       if (next_ip && IS_MOVK_R5 (insn_word))
 277         {
 278           ip = next_ip;
 279           next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 280           auto_depth += insn_word;
 281
 282           next_ip = NEXT_PROLOGUE_INSN (next_ip, limit, &insn_word);
 283           auto_depth += insn_word;
 284         }
 285     }
 286   /* Work out which regs are stored where */
 287   while (next_ip && IS_PUSH (insn_word))
 288     {
 289       ip = next_ip;
 290       next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 291       fsr->regs[r] = after_prolog_fp + auto_depth;
 292       auto_depth += 2;
 293     }
 294
 295   /* The args are always reffed based from the stack pointer */
 296   fi->args_pointer = after_prolog_fp;
 297   /* Locals are always reffed based from the fp */
 298   fi->locals_pointer = after_prolog_fp;
 299   /* The PC is at a known place */
 300   fi->from_pc = read_memory_unsigned_integer (after_prolog_fp + 2, BINWORD);
 301
 302   /* Rememeber any others too */
 303   in_frame[PC_REGNUM] = 0;
 304
 305   if (have_fp)
 306     /* We keep the old FP in the SP spot */
 307     fsr->regs[SP_REGNUM] = read_memory_unsigned_integer (fsr->regs[6], BINWORD);
 308   else
 309     fsr->regs[SP_REGNUM] = after_prolog_fp + auto_depth;
 310
 311   return (ip);
 312 }
 313
 314 void
 315 init_extra_frame_info (fromleaf, fi)
 316      int fromleaf;
 317      struct frame_info *fi;
 318 {
 319   fi->fsr = 0;                  /* Not yet allocated */
 320   fi->args_pointer = 0;         /* Unknown */
 321   fi->locals_pointer = 0;       /* Unknown */
 322   fi->from_pc = 0;
 323 }
 324
 325 /* Return the saved PC from this frame.
 326
 327    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
 328    just use the register SRP_REGNUM itself.  */
 329
 330 CORE_ADDR
 331 frame_saved_pc (frame)
 332      struct frame_info *frame;
 333 {
 334   return frame->from_pc;
 335 }
 336
 337 CORE_ADDR
 338 frame_locals_address (fi)
 339      struct frame_info *fi;
 340 {
 341   if (!fi->locals_pointer)
 342     {
 343       struct frame_saved_regs ignore;
 344
 345       get_frame_saved_regs (fi, &ignore);
 346
 347     }
 348   return fi->locals_pointer;
 349 }
 350
 351 /* Return the address of the argument block for the frame
 352    described by FI.  Returns 0 if the address is unknown.  */
 353
 354 CORE_ADDR
 355 frame_args_address (fi)
 356      struct frame_info *fi;
 357 {
 358   if (!fi->args_pointer)
 359     {
 360       struct frame_saved_regs ignore;
 361
 362       get_frame_saved_regs (fi, &ignore);
 363
 364     }
 365
 366   return fi->args_pointer;
 367 }
 368
 369 void
 370 h8300_pop_frame ()
 371 {
 372   unsigned regnum;
 373   struct frame_saved_regs fsr;
 374   struct frame_info *frame = get_current_frame ();
 375
 376   get_frame_saved_regs (frame, &fsr);
 377
 378   for (regnum = 0; regnum < 8; regnum++)
 379     {
 380       if (fsr.regs[regnum])
 381         write_register (regnum, read_memory_integer(fsr.regs[regnum], BINWORD));
 382
 383       flush_cached_frames ();
 384     }
 385 }
 386
 387
 388 struct cmd_list_element *setmemorylist;
 389
 390 static void
 391 h8300_command(args, from_tty)
 392 {
 393   extern int h8300hmode;
 394   h8300hmode = 0;
 395 }
 396
 397 static void
 398 h8300h_command(args, from_tty)
 399 {
 400   extern int h8300hmode;
 401   h8300hmode = 1;
 402 }
 403
 404 static void
 405 set_machine (args, from_tty)
 406      char *args;
 407      int from_tty;
 408 {
 409   printf_unfiltered ("\"set machine\" must be followed by h8300 or h8300h.\n");
 410   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 411 }
 412
 413 /* set_machine_hook is called as the exec file is being opened, but
 414    before the symbol file is opened.  This allows us to set the
 415    h8300hmode flag based on the machine type specified in the exec
 416    file.  This in turn will cause subsequently defined pointer types
 417    to be 16 or 32 bits as appropriate for the machine.  */
 418
 419 static void
 420 set_machine_hook (filename)
 421      char *filename;
 422 {
 423   h8300hmode = (bfd_get_mach (exec_bfd) == bfd_mach_h8300h);
 424 }
 425
 426 void
 427 _initialize_h8300m ()
 428 {
 429   add_prefix_cmd ("machine", no_class, set_machine,
 430                   "set the machine type", &setmemorylist, "set machine ", 0,
 431                   &setlist);
 432
 433   add_cmd ("h8300", class_support, h8300_command,
 434            "Set machine to be H8/300.", &setmemorylist);
 435
 436   add_cmd ("h8300h", class_support, h8300h_command,
 437            "Set machine to be H8/300H.", &setmemorylist);
 438
 439   /* Add a hook to set the machine type when we're loading a file. */
 440
 441   specify_exec_file_hook(set_machine_hook);
 442 }
 443
 444
 445
 446 void
 447 print_register_hook (regno)
 448 {
 449   if (regno == 8)
 450     {
 451       /* CCR register */
 452       int C, Z, N, V;
 453       unsigned char b[4];
 454       unsigned char l;
 455       read_relative_register_raw_bytes (regno, b);
 456       l = b[REGISTER_VIRTUAL_SIZE(8) -1];
 457       printf_unfiltered ("\t");
 458       printf_unfiltered ("I-%d - ", (l & 0x80) != 0);
 459       printf_unfiltered ("H-%d - ", (l & 0x20) != 0);
 460       N = (l & 0x8) != 0;
 461       Z = (l & 0x4) != 0;
 462       V = (l & 0x2) != 0;
 463       C = (l & 0x1) != 0;
 464       printf_unfiltered ("N-%d ", N);
 465       printf_unfiltered ("Z-%d ", Z);
 466       printf_unfiltered ("V-%d ", V);
 467       printf_unfiltered ("C-%d ", C);
 468       if ((C | Z) == 0)
 469         printf_unfiltered ("u> ");
 470       if ((C | Z) == 1)
 471         printf_unfiltered ("u<= ");
 472       if ((C == 0))
 473         printf_unfiltered ("u>= ");
 474       if (C == 1)
 475         printf_unfiltered ("u< ");
 476       if (Z == 0)
 477         printf_unfiltered ("!= ");
 478       if (Z == 1)
 479         printf_unfiltered ("== ");
 480       if ((N ^ V) == 0)
 481         printf_unfiltered (">= ");
 482       if ((N ^ V) == 1)
 483         printf_unfiltered ("< ");
 484       if ((Z | (N ^ V)) == 0)
 485         printf_unfiltered ("> ");
 486       if ((Z | (N ^ V)) == 1)
 487         printf_unfiltered ("<= ");
 488     }
 489 }
 490
 491 void
 492 _initialize_h8300_tdep ()
 493 {
 494   tm_print_insn = gdb_print_insn_h8300;
 495 }