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 & 0xfff0)==0x6df0)
  52 #define IS_PUSH_FP(x) (x == 0x6df6)
  53 #define IS_MOVE_FP(x) (x == 0x0d76 || x == 0x0ff6)
  54 #define IS_MOV_SP_FP(x) (x == 0x0d76 || x == 0x0ff6)
  55 #define IS_SUB2_SP(x) (x==0x1b87)
  56 #define IS_SUB4_SP(x) (x==0x1b97)
  57 #define IS_SUBL_SP(x) (x==0x7a37)
  58 #define IS_MOVK_R5(x) (x==0x7905)
  59 #define IS_SUB_R5SP(x) (x==0x1957)
  60
  61 /* Local function declarations.  */
  62
  63 static CORE_ADDR examine_prologue ();
  64 static void set_machine_hook PARAMS ((char *filename));
  65
  66 void frame_find_saved_regs ();
  67 CORE_ADDR
  68 h8300_skip_prologue (start_pc)
  69      CORE_ADDR start_pc;
  70 {
  71   short int w;
  72   int adjust = 0;
  73
  74   w = read_memory_unsigned_integer (start_pc, 2);
  75   if (w == 0x0100)
  76     {
  77       w = read_memory_unsigned_integer (start_pc + 2, 2);
  78       adjust = 2;
  79     }
  80
  81   /* Skip past all push insns */
  82   while (IS_PUSH_FP (w))
  83     {
  84       start_pc += 2 + adjust;
  85       w = read_memory_unsigned_integer (start_pc, 2);
  86     }
  87
  88   /* Skip past a move to FP */
  89   if (IS_MOVE_FP (w))
  90     {
  91       start_pc += 2;
  92       w = read_memory_unsigned_integer (start_pc, 2);
  93     }
  94
  95   /* Skip the stack adjust */
  96
  97   if (IS_MOVK_R5 (w))
  98     {
  99       start_pc += 2;
 100       w = read_memory_unsigned_integer (start_pc, 2);
 101     }
 102   if (IS_SUB_R5SP (w))
 103     {
 104       start_pc += 2;
 105       w = read_memory_unsigned_integer (start_pc, 2);
 106     }
 107   while (IS_SUB2_SP (w) || IS_SUB4_SP (w))
 108     {
 109       start_pc += 2;
 110       w = read_memory_unsigned_integer (start_pc, 2);
 111     }
 112
 113   if (IS_SUBL_SP (w))
 114     start_pc += 6;
 115
 116   return start_pc;
 117 }
 118
 119 int
 120 gdb_print_insn_h8300 (memaddr, info)
 121      bfd_vma memaddr;
 122      disassemble_info *info;
 123 {
 124   if (h8300smode)
 125     return print_insn_h8300s (memaddr, info);
 126   else if (h8300hmode)
 127     return print_insn_h8300h (memaddr, info);
 128   else
 129     return print_insn_h8300 (memaddr, info);
 130 }
 131
 132 /* Given a GDB frame, determine the address of the calling function's frame.
 133    This will be used to create a new GDB frame struct, and then
 134    INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame.
 135
 136    For us, the frame address is its stack pointer value, so we look up
 137    the function prologue to determine the caller's sp value, and return it.  */
 138
 139 CORE_ADDR
 140 h8300_frame_chain (thisframe)
 141      struct frame_info *thisframe;
 142 {
 143   frame_find_saved_regs (thisframe, (struct frame_saved_regs *) 0);
 144   return thisframe->fsr->regs[SP_REGNUM];
 145 }
 146
 147 /* Put here the code to store, into a struct frame_saved_regs,
 148    the addresses of the saved registers of frame described by FRAME_INFO.
 149    This includes special registers such as pc and fp saved in special
 150    ways in the stack frame.  sp is even more special:
 151    the address we return for it IS the sp for the next frame.
 152
 153    We cache the result of doing this in the frame_cache_obstack, since
 154    it is fairly expensive.  */
 155
 156 void
 157 frame_find_saved_regs (fi, fsr)
 158      struct frame_info *fi;
 159      struct frame_saved_regs *fsr;
 160 {
 161   register struct frame_saved_regs *cache_fsr;
 162   extern struct obstack frame_cache_obstack;
 163   CORE_ADDR ip;
 164   struct symtab_and_line sal;
 165   CORE_ADDR limit;
 166
 167   if (!fi->fsr)
 168     {
 169       cache_fsr = (struct frame_saved_regs *)
 170         obstack_alloc (&frame_cache_obstack,
 171                        sizeof (struct frame_saved_regs));
 172       memset (cache_fsr, '\0', sizeof (struct frame_saved_regs));
 173
 174       fi->fsr = cache_fsr;
 175
 176       /* Find the start and end of the function prologue.  If the PC
 177          is in the function prologue, we only consider the part that
 178          has executed already.  */
 179
 180       ip = get_pc_function_start (fi->pc);
 181       sal = find_pc_line (ip, 0);
 182       limit = (sal.end && sal.end < fi->pc) ? sal.end : fi->pc;
 183
 184       /* This will fill in fields in *fi as well as in cache_fsr.  */
 185       examine_prologue (ip, limit, fi->frame, cache_fsr, fi);
 186     }
 187
 188   if (fsr)
 189     *fsr = *fi->fsr;
 190 }
 191
 192 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 193    is not the address of a valid instruction, the address of the next
 194    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 195    of the instruction.*/
 196
 197 CORE_ADDR
 198 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 199      CORE_ADDR addr;
 200      CORE_ADDR lim;
 201      INSN_WORD *pword1;
 202 {
 203   char buf[2];
 204   if (addr < lim + 8)
 205     {
 206       read_memory (addr, buf, 2);
 207       *pword1 = extract_signed_integer (buf, 2);
 208
 209       return addr + 2;
 210     }
 211   return 0;
 212 }
 213
 214 /* Examine the prologue of a function.  `ip' points to the first instruction.
 215    `limit' is the limit of the prologue (e.g. the addr of the first
 216    linenumber, or perhaps the program counter if we're stepping through).
 217    `frame_sp' is the stack pointer value in use in this frame.
 218    `fsr' is a pointer to a frame_saved_regs structure into which we put
 219    info about the registers saved by this frame.
 220    `fi' is a struct frame_info pointer; we fill in various fields in it
 221    to reflect the offsets of the arg pointer and the locals pointer.  */
 222
 223 static CORE_ADDR
 224 examine_prologue (ip, limit, after_prolog_fp, fsr, fi)
 225      register CORE_ADDR ip;
 226      register CORE_ADDR limit;
 227      CORE_ADDR after_prolog_fp;
 228      struct frame_saved_regs *fsr;
 229      struct frame_info *fi;
 230 {
 231   register CORE_ADDR next_ip;
 232   int r;
 233   int have_fp = 0;
 234   INSN_WORD insn_word;
 235   /* Number of things pushed onto stack, starts at 2/4, 'cause the
 236      PC is already there */
 237   unsigned int reg_save_depth = h8300hmode ? 4 : 2;
 238
 239   unsigned int auto_depth = 0;  /* Number of bytes of autos */
 240
 241   char in_frame[11];            /* One for each reg */
 242
 243   int adjust = 0;
 244
 245   memset (in_frame, 1, 11);
 246   for (r = 0; r < 8; r++)
 247     {
 248       fsr->regs[r] = 0;
 249     }
 250   if (after_prolog_fp == 0)
 251     {
 252       after_prolog_fp = read_register (SP_REGNUM);
 253     }
 254   if (ip == 0 || ip & (h8300hmode ? ~0xffffff : ~0xffff))
 255     return 0;
 256
 257   next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 258
 259   if (insn_word == 0x0100)
 260     {
 261       insn_word = read_memory_unsigned_integer (ip + 2, 2);
 262       adjust = 2;
 263     }
 264
 265   /* Skip over any fp push instructions */
 266   fsr->regs[6] = after_prolog_fp;
 267   while (next_ip && IS_PUSH_FP (insn_word))
 268     {
 269       ip = next_ip + adjust;
 270
 271       in_frame[insn_word & 0x7] = reg_save_depth;
 272       next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 273       reg_save_depth += 2 + adjust;
 274     }
 275
 276   /* Is this a move into the fp */
 277   if (next_ip && IS_MOV_SP_FP (insn_word))
 278     {
 279       ip = next_ip;
 280       next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 281       have_fp = 1;
 282     }
 283
 284   /* Skip over any stack adjustment, happens either with a number of
 285      sub#2,sp or a mov #x,r5 sub r5,sp */
 286
 287   if (next_ip && (IS_SUB2_SP (insn_word) || IS_SUB4_SP (insn_word)))
 288     {
 289       while (next_ip && (IS_SUB2_SP (insn_word) || IS_SUB4_SP (insn_word)))
 290         {
 291           auto_depth += IS_SUB2_SP (insn_word) ? 2 : 4;
 292           ip = next_ip;
 293           next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 294         }
 295     }
 296   else
 297     {
 298       if (next_ip && IS_MOVK_R5 (insn_word))
 299         {
 300           ip = next_ip;
 301           next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 302           auto_depth += insn_word;
 303
 304           next_ip = NEXT_PROLOGUE_INSN (next_ip, limit, &insn_word);
 305           auto_depth += insn_word;
 306         }
 307       if (next_ip && IS_SUBL_SP (insn_word))
 308         {
 309           ip = next_ip;
 310           auto_depth += read_memory_unsigned_integer (ip, 4);
 311           ip += 4;
 312
 313           next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 314         }
 315     }
 316
 317   /* Work out which regs are stored where */
 318   while (next_ip && IS_PUSH (insn_word))
 319     {
 320       ip = next_ip;
 321       next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn_word);
 322       fsr->regs[r] = after_prolog_fp + auto_depth;
 323       auto_depth += 2;
 324     }
 325
 326   /* The args are always reffed based from the stack pointer */
 327   fi->args_pointer = after_prolog_fp;
 328   /* Locals are always reffed based from the fp */
 329   fi->locals_pointer = after_prolog_fp;
 330   /* The PC is at a known place */
 331   fi->from_pc = read_memory_unsigned_integer (after_prolog_fp + BINWORD, BINWORD);
 332
 333   /* Rememeber any others too */
 334   in_frame[PC_REGNUM] = 0;
 335
 336   if (have_fp)
 337     /* We keep the old FP in the SP spot */
 338     fsr->regs[SP_REGNUM] = read_memory_unsigned_integer (fsr->regs[6], BINWORD);
 339   else
 340     fsr->regs[SP_REGNUM] = after_prolog_fp + auto_depth;
 341
 342   return (ip);
 343 }
 344
 345 void
 346 init_extra_frame_info (fromleaf, fi)
 347      int fromleaf;
 348      struct frame_info *fi;
 349 {
 350   fi->fsr = 0;                  /* Not yet allocated */
 351   fi->args_pointer = 0;         /* Unknown */
 352   fi->locals_pointer = 0;       /* Unknown */
 353   fi->from_pc = 0;
 354 }
 355
 356 /* Return the saved PC from this frame.
 357
 358    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
 359    just use the register SRP_REGNUM itself.  */
 360
 361 CORE_ADDR
 362 frame_saved_pc (frame)
 363      struct frame_info *frame;
 364 {
 365   return frame->from_pc;
 366 }
 367
 368 CORE_ADDR
 369 frame_locals_address (fi)
 370      struct frame_info *fi;
 371 {
 372   if (!fi->locals_pointer)
 373     {
 374       struct frame_saved_regs ignore;
 375
 376       get_frame_saved_regs (fi, &ignore);
 377
 378     }
 379   return fi->locals_pointer;
 380 }
 381
 382 /* Return the address of the argument block for the frame
 383    described by FI.  Returns 0 if the address is unknown.  */
 384
 385 CORE_ADDR
 386 frame_args_address (fi)
 387      struct frame_info *fi;
 388 {
 389   if (!fi->args_pointer)
 390     {
 391       struct frame_saved_regs ignore;
 392
 393       get_frame_saved_regs (fi, &ignore);
 394
 395     }
 396
 397   return fi->args_pointer;
 398 }
 399
 400 void
 401 h8300_pop_frame ()
 402 {
 403   unsigned regnum;
 404   struct frame_saved_regs fsr;
 405   struct frame_info *frame = get_current_frame ();
 406
 407   get_frame_saved_regs (frame, &fsr);
 408
 409   for (regnum = 0; regnum < 8; regnum++)
 410     {
 411       /* Don't forget SP_REGNUM is a frame_saved_regs struct is the
 412          actual value we want, not the address of the value we want.  */
 413       if (fsr.regs[regnum] && regnum != SP_REGNUM)
 414         write_register (regnum, read_memory_integer(fsr.regs[regnum], BINWORD));
 415       else if (fsr.regs[regnum] && regnum == SP_REGNUM)
 416         write_register (regnum, fsr.regs[regnum]);
 417     }
 418
 419   /* Don't forget the update the PC too!  */
 420   write_pc (frame->from_pc);
 421   flush_cached_frames ();
 422 }
 423
 424
 425 struct cmd_list_element *setmemorylist;
 426
 427 static void
 428 h8300_command(args, from_tty)
 429 {
 430   extern int h8300hmode;
 431   h8300hmode = 0;
 432   h8300smode = 0;
 433 }
 434
 435 static void
 436 h8300h_command(args, from_tty)
 437 {
 438   extern int h8300hmode;
 439   h8300hmode = 1;
 440   h8300smode = 0;
 441 }
 442 static void
 443 h8300s_command(args, from_tty)
 444 {
 445   extern int h8300smode;
 446   extern int h8300hmode;
 447   h8300smode = 1;
 448   h8300hmode = 1;
 449 }
 450
 451
 452 static void
 453 set_machine (args, from_tty)
 454      char *args;
 455      int from_tty;
 456 {
 457   printf_unfiltered ("\"set machine\" must be followed by h8300, h8300h");
 458   printf_unfiltered ("or h8300s");
 459   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 460 }
 461
 462 /* set_machine_hook is called as the exec file is being opened, but
 463    before the symbol file is opened.  This allows us to set the
 464    h8300hmode flag based on the machine type specified in the exec
 465    file.  This in turn will cause subsequently defined pointer types
 466    to be 16 or 32 bits as appropriate for the machine.  */
 467
 468 static void
 469 set_machine_hook (filename)
 470      char *filename;
 471 {
 472   if (bfd_get_mach (exec_bfd) == bfd_mach_h8300s)
 473     {
 474       h8300smode = 1;
 475       h8300hmode = 1;
 476     }
 477   else
 478     if (bfd_get_mach (exec_bfd) == bfd_mach_h8300h)
 479     {
 480       h8300smode = 0;
 481       h8300hmode = 1;
 482     }
 483   else
 484     {
 485       h8300smode = 0;
 486       h8300hmode = 0;
 487     }
 488 }
 489
 490 void
 491 _initialize_h8300m ()
 492 {
 493   add_prefix_cmd ("machine", no_class, set_machine,
 494                   "set the machine type", &setmemorylist, "set machine ", 0,
 495                   &setlist);
 496
 497   add_cmd ("h8300", class_support, h8300_command,
 498            "Set machine to be H8/300.", &setmemorylist);
 499
 500   add_cmd ("h8300h", class_support, h8300h_command,
 501            "Set machine to be H8/300H.", &setmemorylist);
 502
 503   add_cmd ("h8300s", class_support, h8300s_command,
 504            "Set machine to be H8/300S.", &setmemorylist);
 505
 506   /* Add a hook to set the machine type when we're loading a file. */
 507
 508   specify_exec_file_hook(set_machine_hook);
 509 }
 510
 511
 512
 513 void
 514 print_register_hook (regno)
 515 {
 516   if (regno == 8)
 517     {
 518       /* CCR register */
 519       int C, Z, N, V;
 520       unsigned char b[4];
 521       unsigned char l;
 522       read_relative_register_raw_bytes (regno, b);
 523       l = b[REGISTER_VIRTUAL_SIZE(8) -1];
 524       printf_unfiltered ("\t");
 525       printf_unfiltered ("I-%d - ", (l & 0x80) != 0);
 526       printf_unfiltered ("H-%d - ", (l & 0x20) != 0);
 527       N = (l & 0x8) != 0;
 528       Z = (l & 0x4) != 0;
 529       V = (l & 0x2) != 0;
 530       C = (l & 0x1) != 0;
 531       printf_unfiltered ("N-%d ", N);
 532       printf_unfiltered ("Z-%d ", Z);
 533       printf_unfiltered ("V-%d ", V);
 534       printf_unfiltered ("C-%d ", C);
 535       if ((C | Z) == 0)
 536         printf_unfiltered ("u> ");
 537       if ((C | Z) == 1)
 538         printf_unfiltered ("u<= ");
 539       if ((C == 0))
 540         printf_unfiltered ("u>= ");
 541       if (C == 1)
 542         printf_unfiltered ("u< ");
 543       if (Z == 0)
 544         printf_unfiltered ("!= ");
 545       if (Z == 1)
 546         printf_unfiltered ("== ");
 547       if ((N ^ V) == 0)
 548         printf_unfiltered (">= ");
 549       if ((N ^ V) == 1)
 550         printf_unfiltered ("< ");
 551       if ((Z | (N ^ V)) == 0)
 552         printf_unfiltered ("> ");
 553       if ((Z | (N ^ V)) == 1)
 554         printf_unfiltered ("<= ");
 555     }
 556 }
 557
 558 void
 559 _initialize_h8300_tdep ()
 560 {
 561   tm_print_insn = gdb_print_insn_h8300;
 562 }