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
  33 #undef NUM_REGS
  34 #define NUM_REGS 11
  35
  36 #define UNSIGNED_SHORT(X) ((X) & 0xffff)
  37
  38 /* an easy to debug H8 stack frame looks like:
  39 0x6df6          push    r6
  40 0x0d76          mov.w   r7,r6
  41 0x6dfn          push    reg
  42 0x7905 nnnn     mov.w  #n,r5    or   0x1b87  subs #2,sp
  43 0x1957          sub.w  r5,sp
  44
  45  */
  46
  47 #define IS_PUSH(x) ((x & 0xff00)==0x6d00)
  48 #define IS_PUSH_FP(x) (x == 0x6df6)
  49 #define IS_MOVE_FP(x) (x == 0x0d76)
  50 #define IS_MOV_SP_FP(x) (x == 0x0d76)
  51 #define IS_SUB2_SP(x) (x==0x1b87)
  52 #define IS_MOVK_R5(x) (x==0x7905)
  53 #define IS_SUB_R5SP(x) (x==0x1957)
  54
  55 static CORE_ADDR examine_prologue ();
  56
  57 void frame_find_saved_regs ();
  58 CORE_ADDR
  59 h8300_skip_prologue (start_pc)
  60      CORE_ADDR start_pc;
  61 {
  62   short int w;
  63
  64   w = read_memory_unsigned_integer (start_pc, 2);
  65   /* Skip past all push insns */
  66   while (IS_PUSH_FP (w))
  67     {
  68       start_pc += 2;
  69       w = read_memory_unsigned_integer (start_pc, 2);
  70     }
  71
  72   /* Skip past a move to FP */
  73   if (IS_MOVE_FP (w))
  74     {
  75       start_pc += 2;
  76       w = read_memory_unsigned_integer (start_pc, 2);
  77     }
  78
  79   /* Skip the stack adjust */
  80
  81   if (IS_MOVK_R5 (w))
  82     {
  83       start_pc += 2;
  84       w = read_memory_unsigned_integer (start_pc, 2);
  85     }
  86   if (IS_SUB_R5SP (w))
  87     {
  88       start_pc += 2;
  89       w = read_memory_unsigned_integer (start_pc, 2);
  90     }
  91   while (IS_SUB2_SP (w))
  92     {
  93       start_pc += 2;
  94       w = read_memory_unsigned_integer (start_pc, 2);
  95     }
  96
  97   return start_pc;
  98 }
  99
 100 int
 101 gdb_print_insn_h8300 (memaddr, info)
 102      bfd_vma memaddr;
 103      disassemble_info *info;
 104 {
 105   if (h8300hmode)
 106     return print_insn_h8300h (memaddr, info);
 107   else
 108     return print_insn_h8300 (memaddr, info);
 109 }
 110
 111 /* Given a GDB frame, determine the address of the calling function's frame.
 112    This will be used to create a new GDB frame struct, and then
 113    INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame.
 114
 115    For us, the frame address is its stack pointer value, so we look up
 116    the function prologue to determine the caller's sp value, and return it.  */
 117
 118 CORE_ADDR
 119 h8300_frame_chain (thisframe)
 120      struct frame_info *thisframe;
 121 {
 122   frame_find_saved_regs (thisframe, (struct frame_saved_regs *) 0);
 123   return thisframe->fsr->regs[SP_REGNUM];
 124 }
 125
 126 /* Put here the code to store, into a struct frame_saved_regs,
 127    the addresses of the saved registers of frame described by FRAME_INFO.
 128    This includes special registers such as pc and fp saved in special
 129    ways in the stack frame.  sp is even more special:
 130    the address we return for it IS the sp for the next frame.
 131
 132    We cache the result of doing this in the frame_cache_obstack, since
 133    it is fairly expensive.  */
 134
 135 void
 136 frame_find_saved_regs (fi, fsr)
 137      struct frame_info *fi;
 138      struct frame_saved_regs *fsr;
 139 {
 140   register CORE_ADDR next_addr;
 141   register CORE_ADDR *saved_regs;
 142   register int regnum;
 143   register struct frame_saved_regs *cache_fsr;
 144   extern struct obstack frame_cache_obstack;
 145   CORE_ADDR ip;
 146   struct symtab_and_line sal;
 147   CORE_ADDR limit;
 148
 149   if (!fi->fsr)
 150     {
 151       cache_fsr = (struct frame_saved_regs *)
 152         obstack_alloc (&frame_cache_obstack,
 153                        sizeof (struct frame_saved_regs));
 154       memset (cache_fsr, '\0', sizeof (struct frame_saved_regs));
 155
 156       fi->fsr = cache_fsr;
 157
 158       /* Find the start and end of the function prologue.  If the PC
 159          is in the function prologue, we only consider the part that
 160          has executed already.  */
 161
 162       ip = get_pc_function_start (fi->pc);
 163       sal = find_pc_line (ip, 0);
 164       limit = (sal.end && sal.end < fi->pc) ? sal.end : fi->pc;
 165
 166       /* This will fill in fields in *fi as well as in cache_fsr.  */
 167       examine_prologue (ip, limit, fi->frame, cache_fsr, fi);
 168     }
 169
 170   if (fsr)
 171     *fsr = *fi->fsr;
 172 }
 173
 174 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 175    is not the address of a valid instruction, the address of the next
 176    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 177    of the instruction.*/
 178
 179 CORE_ADDR
 180 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 181      CORE_ADDR addr;
 182      CORE_ADDR lim;
 183      INSN_WORD *pword1;
 184 {
 185   char buf[2];
 186   if (addr < lim + 8)
 187     {
 188       read_memory (addr, buf, 2);
 189       *pword1 = extract_signed_integer (buf, 2);
 190
 191       return addr + 2;
 192     }
 193   return 0;
 194 }
 195
 196 /* Examine the prologue of a function.  `ip' points to the first instruction.
 197    `limit' is the limit of the prologue (e.g. the addr of the first
 198    linenumber, or perhaps the program counter if we're stepping through).
 199    `frame_sp' is the stack pointer value in use in this frame.
 200    `fsr' is a pointer to a frame_saved_regs structure into which we put
 201    info about the registers saved by this frame.
 202    `fi' is a struct frame_info pointer; we fill in various fields in it
 203    to reflect the offsets of the arg pointer and the locals pointer.  */
 204
 205 static CORE_ADDR
 206 examine_prologue (ip, limit, after_prolog_fp, fsr, fi)
 207      register CORE_ADDR ip;
 208      register CORE_ADDR limit;
 209      CORE_ADDR after_prolog_fp;
 210      struct frame_saved_regs *fsr;
 211      struct frame_info *fi;
 212 {
 213   register CORE_ADDR next_ip;
 214   int r;
 215   int i;
 216   int have_fp = 0;
 217   register int src;
 218   register struct pic_prologue_code *pcode;
 219   INSN_WORD insn_word;
 220   int size, offset;
 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 void
 414 _initialize_h8300m ()
 415 {
 416   add_prefix_cmd ("machine", no_class, set_machine,
 417                   "set the machine type", &setmemorylist, "set machine ", 0,
 418                   &setlist);
 419
 420   add_cmd ("h8300", class_support, h8300_command,
 421            "Set machine to be H8/300.", &setmemorylist);
 422
 423   add_cmd ("h8300h", class_support, h8300h_command,
 424            "Set machine to be H8/300H.", &setmemorylist);
 425 }
 426
 427
 428
 429 void
 430 print_register_hook (regno)
 431 {
 432   if (regno == 8)
 433     {
 434       /* CCR register */
 435       int C, Z, N, V;
 436       unsigned char b[4];
 437       unsigned char l;
 438       read_relative_register_raw_bytes (regno, b);
 439       l = b[REGISTER_VIRTUAL_SIZE(8) -1];
 440       printf_unfiltered ("\t");
 441       printf_unfiltered ("I-%d - ", (l & 0x80) != 0);
 442       printf_unfiltered ("H-%d - ", (l & 0x20) != 0);
 443       N = (l & 0x8) != 0;
 444       Z = (l & 0x4) != 0;
 445       V = (l & 0x2) != 0;
 446       C = (l & 0x1) != 0;
 447       printf_unfiltered ("N-%d ", N);
 448       printf_unfiltered ("Z-%d ", Z);
 449       printf_unfiltered ("V-%d ", V);
 450       printf_unfiltered ("C-%d ", C);
 451       if ((C | Z) == 0)
 452         printf_unfiltered ("u> ");
 453       if ((C | Z) == 1)
 454         printf_unfiltered ("u<= ");
 455       if ((C == 0))
 456         printf_unfiltered ("u>= ");
 457       if (C == 1)
 458         printf_unfiltered ("u< ");
 459       if (Z == 0)
 460         printf_unfiltered ("!= ");
 461       if (Z == 1)
 462         printf_unfiltered ("== ");
 463       if ((N ^ V) == 0)
 464         printf_unfiltered (">= ");
 465       if ((N ^ V) == 1)
 466         printf_unfiltered ("< ");
 467       if ((Z | (N ^ V)) == 0)
 468         printf_unfiltered ("> ");
 469       if ((Z | (N ^ V)) == 1)
 470         printf_unfiltered ("<= ");
 471     }
 472 }
 473
 474 void
 475 _initialize_h8300_tdep ()
 476 {
 477   tm_print_insn = gdb_print_insn_h8300;
 478 }