gdb/z8k-tdep.c

   1 /* Target-machine dependent code for Zilog Z8000, for GDB.
   2    Copyright (C) 1992,1993 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., 675 Mass Ave, Cambridge, MA 02139, 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 "gdbcmd.h"
  30 #include "gdbtypes.h"
  31 #include "dis-asm.h"
  32 /* Return the saved PC from this frame.
  33
  34    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  35    just use the register SRP_REGNUM itself.  */
  36
  37 CORE_ADDR
  38 frame_saved_pc (frame)
  39      FRAME frame;
  40 {
  41   return (read_memory_pointer (frame->frame + (BIG ? 4 : 2)));
  42 }
  43
  44 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  45 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  46 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  47 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  48 #define IS_SUB2_SP(x) (x==0x1b87)
  49 #define IS_MOVK_R5(x) (x==0x7905)
  50 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  51 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  52
  53 /* work out how much local space is on the stack and
  54    return the pc pointing to the first push */
  55
  56 static CORE_ADDR
  57 skip_adjust (pc, size)
  58      CORE_ADDR pc;
  59      int *size;
  60 {
  61   *size = 0;
  62
  63   if (IS_PUSH_FP (read_memory_short (pc))
  64       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  65     {
  66       /* This is a function with an explict frame pointer */
  67       pc += 4;
  68       *size += 2;               /* remember the frame pointer */
  69     }
  70
  71   /* remember any stack adjustment */
  72   if (IS_SUB_SP (read_memory_short (pc)))
  73     {
  74       *size += read_memory_short (pc + 2);
  75       pc += 4;
  76     }
  77   return pc;
  78 }
  79
  80 int
  81 examine_frame (pc, regs, sp)
  82      CORE_ADDR pc;
  83      struct frame_saved_regs *regs;
  84      CORE_ADDR sp;
  85 {
  86   int w = read_memory_short (pc);
  87   int offset = 0;
  88   int regno;
  89
  90   for (regno = 0; regno < NUM_REGS; regno++)
  91     regs->regs[regno] = 0;
  92
  93   while (IS_PUSHW (w) || IS_PUSHL (w))
  94     {
  95       /* work out which register is being pushed to where */
  96       if (IS_PUSHL (w))
  97         {
  98           regs->regs[w & 0xf] = offset;
  99           regs->regs[(w & 0xf) + 1] = offset + 2;
 100           offset += 4;
 101         }
 102       else
 103         {
 104           regs->regs[w & 0xf] = offset;
 105           offset += 2;
 106         }
 107       pc += 2;
 108       w = read_memory_short (pc);
 109     }
 110
 111   if (IS_MOVE_FP (w))
 112     {
 113       /* We know the fp */
 114
 115     }
 116   else if (IS_SUB_SP (w))
 117     {
 118       /* Subtracting a value from the sp, so were in a function
 119        which needs stack space for locals, but has no fp.  We fake up
 120        the values as if we had an fp */
 121       regs->regs[FP_REGNUM] = sp;
 122     }
 123   else
 124     {
 125       /* This one didn't have an fp, we'll fake it up */
 126       regs->regs[SP_REGNUM] = sp;
 127     }
 128   /* stack pointer contains address of next frame */
 129   /*  regs->regs[fp_regnum()] = fp;*/
 130   regs->regs[SP_REGNUM] = sp;
 131   return pc;
 132 }
 133
 134 CORE_ADDR
 135 z8k_skip_prologue (start_pc)
 136      CORE_ADDR start_pc;
 137 {
 138   struct frame_saved_regs dummy;
 139
 140   return examine_frame (start_pc, &dummy, 0);
 141 }
 142
 143 CORE_ADDR
 144 addr_bits_remove (x)
 145      CORE_ADDR x;
 146 {
 147   return x & PTR_MASK;
 148 }
 149
 150 read_memory_pointer (x)
 151      CORE_ADDR x;
 152 {
 153
 154   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 155 }
 156
 157 FRAME_ADDR
 158 frame_chain (thisframe)
 159      FRAME thisframe;
 160 {
 161   if (thisframe->prev == 0)
 162     {
 163       /* This is the top of the stack, let's get the sp for real */
 164     }
 165   if (!inside_entry_file ((thisframe)->pc))
 166     {
 167       return read_memory_pointer ((thisframe)->frame);
 168     }
 169   return 0;
 170 }
 171
 172 init_frame_pc ()
 173 {
 174   abort ();
 175 }
 176
 177 /* Put here the code to store, into a struct frame_saved_regs,
 178    the addresses of the saved registers of frame described by FRAME_INFO.
 179    This includes special registers such as pc and fp saved in special
 180    ways in the stack frame.  sp is even more special:
 181    the address we return for it IS the sp for the next frame.  */
 182
 183 void
 184 get_frame_saved_regs (frame_info, frame_saved_regs)
 185      struct frame_info *frame_info;
 186      struct frame_saved_regs *frame_saved_regs;
 187
 188 {
 189   CORE_ADDR pc;
 190   int w;
 191
 192   memset (frame_saved_regs, '\0', sizeof (*frame_saved_regs));
 193   pc = get_pc_function_start (frame_info->pc);
 194
 195 /* wander down the instruction stream */
 196   examine_frame (pc, frame_saved_regs, frame_info->frame);
 197
 198 }
 199
 200 void
 201 z8k_push_dummy_frame ()
 202 {
 203   abort ();
 204 }
 205
 206 int
 207 print_insn (memaddr, stream)
 208      CORE_ADDR memaddr;
 209      FILE *stream;
 210 {
 211   disassemble_info info;
 212
 213   GDB_INIT_DISASSEMBLE_INFO(info, stream);
 214
 215   if (BIG)
 216     {
 217       return print_insn_z8001 ((bfd_vma) memaddr, &info);
 218     }
 219   else
 220     {
 221       return print_insn_z8002 ((bfd_vma) memaddr, &info);
 222     }
 223 }
 224
 225 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 226    is not the address of a valid instruction, the address of the next
 227    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 228    of the instruction.*/
 229
 230 CORE_ADDR
 231 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 232      CORE_ADDR addr;
 233      CORE_ADDR lim;
 234      short *pword1;
 235 {
 236   char buf[2];
 237   if (addr < lim + 8)
 238     {
 239       read_memory (addr, buf, 2);
 240       *pword1 = extract_signed_integer (buf, 2);
 241
 242       return addr + 2;
 243     }
 244   return 0;
 245 }
 246
 247 /* Put here the code to store, into a struct frame_saved_regs,
 248    the addresses of the saved registers of frame described by FRAME_INFO.
 249    This includes special registers such as pc and fp saved in special
 250    ways in the stack frame.  sp is even more special:
 251    the address we return for it IS the sp for the next frame.
 252
 253    We cache the result of doing this in the frame_cache_obstack, since
 254    it is fairly expensive.  */
 255
 256 void
 257 frame_find_saved_regs (fip, fsrp)
 258      struct frame_info *fip;
 259      struct frame_saved_regs *fsrp;
 260 {
 261   int locals;
 262   CORE_ADDR pc;
 263   CORE_ADDR adr;
 264   int i;
 265
 266   memset (fsrp, 0, sizeof *fsrp);
 267
 268   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 269
 270   {
 271     adr = fip->frame - locals;
 272     for (i = 0; i < 8; i++)
 273       {
 274         int word = read_memory_short (pc);
 275
 276         pc += 2;
 277         if (IS_PUSHL (word))
 278           {
 279             fsrp->regs[word & 0xf] = adr;
 280             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 281             adr -= 4;
 282           }
 283         else if (IS_PUSHW (word))
 284           {
 285             fsrp->regs[word & 0xf] = adr;
 286             adr -= 2;
 287           }
 288         else
 289           break;
 290       }
 291
 292   }
 293
 294   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 295   fsrp->regs[FP_REGNUM] = fip->frame;
 296
 297 }
 298
 299 int
 300 saved_pc_after_call ()
 301 {
 302   return addr_bits_remove
 303     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 304 }
 305
 306
 307 extract_return_value(type, regbuf, valbuf)
 308 struct type *type;
 309 char *regbuf;
 310 char *valbuf;
 311 {
 312   int b;
 313   int len = TYPE_LENGTH(type);
 314
 315   for (b = 0; b < len; b += 2) {
 316     int todo = len - b;
 317     if (todo > 2)
 318       todo = 2;
 319     memcpy(valbuf + b, regbuf + b, todo);
 320   }
 321 }
 322
 323 void
 324 write_return_value(type, valbuf)
 325 struct type *type;
 326 char *valbuf;
 327 {
 328   int reg;
 329   int len;
 330   for (len = 0; len <  TYPE_LENGTH(type); len += 2)
 331     {
 332       write_register_bytes(REGISTER_BYTE(len /2  + 2), valbuf + len, 2);
 333     }
 334 }
 335
 336 void
 337 store_struct_return(addr, sp)
 338 CORE_ADDR addr;
 339 CORE_ADDR sp;
 340 {
 341   write_register(2, addr);
 342 }
 343
 344
 345 void
 346 print_register_hook (regno)
 347      int regno;
 348 {
 349   if ((regno & 1) == 0 && regno < 16)
 350     {
 351       unsigned short l[2];
 352
 353       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 354       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 355       printf ("\t");
 356       printf ("%04x%04x", l[0], l[1]);
 357     }
 358
 359   if ((regno & 3) == 0 && regno < 16)
 360     {
 361       unsigned short l[4];
 362
 363       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 364       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 365       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 366       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 367
 368       printf ("\t");
 369       printf ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 370     }
 371   if (regno == 15)
 372     {
 373       unsigned short rval;
 374       int i;
 375
 376       read_relative_register_raw_bytes (regno, (char *) (&rval));
 377
 378       printf ("\n");
 379       for (i = 0; i < 10; i += 2)
 380         {
 381           printf ("(sp+%d=%04x)", i, read_memory_short (rval + i));
 382         }
 383     }
 384
 385 }
 386
 387 void
 388 register_convert_to_virtual (regnum, from, to)
 389      unsigned char *from;
 390      unsigned char *to;
 391 {
 392   to[0] = from[0];
 393   to[1] = from[1];
 394   to[2] = from[2];
 395   to[3] = from[3];
 396 }
 397
 398 void
 399 register_convert_to_raw (regnum, to, from)
 400      char *to;
 401      char *from;
 402 {
 403   to[0] = from[0];
 404   to[1] = from[1];
 405   to[2] = from[2];
 406   to[3] = from[3];
 407 }
 408
 409 void
 410 z8k_pop_frame ()
 411 {
 412 }
 413
 414 struct cmd_list_element *setmemorylist;
 415
 416 void
 417 z8k_set_pointer_size (newsize)
 418      int newsize;
 419 {
 420   static int oldsize = 0;
 421
 422   if (oldsize != newsize)
 423     {
 424       printf ("pointer size set to %d bits\n", newsize);
 425       oldsize = newsize;
 426       if (newsize == 32)
 427         {
 428           BIG = 1;
 429         }
 430       else
 431         {
 432           BIG = 0;
 433         }
 434       _initialize_gdbtypes ();
 435     }
 436 }
 437
 438 static void
 439 segmented_command (args, from_tty)
 440      char *args;
 441      int from_tty;
 442 {
 443   z8k_set_pointer_size (32);
 444 }
 445
 446 static void
 447 unsegmented_command (args, from_tty)
 448      char *args;
 449      int from_tty;
 450 {
 451   z8k_set_pointer_size (16);
 452
 453 }
 454
 455 static void
 456 set_memory (args, from_tty)
 457      char *args;
 458      int from_tty;
 459 {
 460   printf ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 461   help_list (setmemorylist, "set memory ", -1, stdout);
 462 }
 463
 464 void
 465 _initialize_z8ktdep ()
 466 {
 467   add_prefix_cmd ("memory", no_class, set_memory,
 468                   "set the memory model", &setmemorylist, "set memory ", 0,
 469                   &setlist);
 470   add_cmd ("segmented", class_support, segmented_command,
 471            "Set segmented memory model.", &setmemorylist);
 472   add_cmd ("unsegmented", class_support, unsegmented_command,
 473            "Set unsegmented memory model.", &setmemorylist);
 474
 475 }