gdb/z8k-tdep.c

   1 /* Target-machine dependent code for Zilog Z8000, for GDB.
   2    Copyright (C) 1992, 1993, 1994 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 "gdbcmd.h"
  30 #include "gdbtypes.h"
  31 #include "dis-asm.h"
  32 #include "gdbcore.h"
  33
  34
  35 /* Return the saved PC from this frame.
  36
  37    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  38    just use the register SRP_REGNUM itself.  */
  39
  40 CORE_ADDR
  41 frame_saved_pc (frame)
  42      struct frame_info *frame;
  43 {
  44   return read_memory_pointer (frame->frame + (BIG ? 4 : 2));
  45 }
  46
  47 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  48 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  49 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  50 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  51 #define IS_SUB2_SP(x) (x==0x1b87)
  52 #define IS_MOVK_R5(x) (x==0x7905)
  53 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  54 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  55
  56 /* work out how much local space is on the stack and
  57    return the pc pointing to the first push */
  58
  59 static CORE_ADDR
  60 skip_adjust (pc, size)
  61      CORE_ADDR pc;
  62      int *size;
  63 {
  64   *size = 0;
  65
  66   if (IS_PUSH_FP (read_memory_short (pc))
  67       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  68     {
  69       /* This is a function with an explict frame pointer */
  70       pc += 4;
  71       *size += 2;               /* remember the frame pointer */
  72     }
  73
  74   /* remember any stack adjustment */
  75   if (IS_SUB_SP (read_memory_short (pc)))
  76     {
  77       *size += read_memory_short (pc + 2);
  78       pc += 4;
  79     }
  80   return pc;
  81 }
  82
  83 static CORE_ADDR examine_frame PARAMS ((CORE_ADDR, CORE_ADDR *regs, CORE_ADDR));
  84 static CORE_ADDR
  85 examine_frame (pc, regs, sp)
  86      CORE_ADDR pc;
  87      CORE_ADDR *regs;
  88      CORE_ADDR sp;
  89 {
  90   int w = read_memory_short (pc);
  91   int offset = 0;
  92   int regno;
  93
  94   for (regno = 0; regno < NUM_REGS; regno++)
  95     regs[regno] = 0;
  96
  97   while (IS_PUSHW (w) || IS_PUSHL (w))
  98     {
  99       /* work out which register is being pushed to where */
 100       if (IS_PUSHL (w))
 101         {
 102           regs[w & 0xf] = offset;
 103           regs[(w & 0xf) + 1] = offset + 2;
 104           offset += 4;
 105         }
 106       else
 107         {
 108           regs[w & 0xf] = offset;
 109           offset += 2;
 110         }
 111       pc += 2;
 112       w = read_memory_short (pc);
 113     }
 114
 115   if (IS_MOVE_FP (w))
 116     {
 117       /* We know the fp */
 118
 119     }
 120   else if (IS_SUB_SP (w))
 121     {
 122       /* Subtracting a value from the sp, so were in a function
 123        which needs stack space for locals, but has no fp.  We fake up
 124        the values as if we had an fp */
 125       regs[FP_REGNUM] = sp;
 126     }
 127   else
 128     {
 129       /* This one didn't have an fp, we'll fake it up */
 130       regs[SP_REGNUM] = sp;
 131     }
 132   /* stack pointer contains address of next frame */
 133   /*  regs[fp_regnum()] = fp;*/
 134   regs[SP_REGNUM] = sp;
 135   return pc;
 136 }
 137
 138 CORE_ADDR
 139 z8k_skip_prologue (start_pc)
 140      CORE_ADDR start_pc;
 141 {
 142   CORE_ADDR dummy[NUM_REGS];
 143
 144   return examine_frame (start_pc, dummy, 0);
 145 }
 146
 147 CORE_ADDR
 148 z8k_addr_bits_remove (addr)
 149      CORE_ADDR addr;
 150 {
 151   return (addr & PTR_MASK);
 152 }
 153
 154 int
 155 read_memory_pointer (x)
 156      CORE_ADDR x;
 157 {
 158   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 159 }
 160
 161 CORE_ADDR
 162 frame_chain (thisframe)
 163      struct frame_info *thisframe;
 164 {
 165   if (thisframe->prev == 0)
 166     {
 167       /* This is the top of the stack, let's get the sp for real */
 168     }
 169   if (!inside_entry_file (thisframe->pc))
 170     {
 171       return read_memory_pointer (thisframe->frame);
 172     }
 173   return 0;
 174 }
 175
 176 void
 177 init_frame_pc ()
 178 {
 179   abort ();
 180 }
 181
 182 /* Put here the code to store, into a struct frame_saved_regs,
 183    the addresses of the saved registers of frame described by FRAME_INFO.
 184    This includes special registers such as pc and fp saved in special
 185    ways in the stack frame.  sp is even more special:
 186    the address we return for it IS the sp for the next frame.  */
 187
 188 void
 189 z8k_frame_init_saved_regs (frame_info)
 190      struct frame_info *frame_info;
 191 {
 192   CORE_ADDR pc;
 193   int w;
 194
 195   frame_saved_regs_zalloc (frame_info);
 196   pc = get_pc_function_start (frame_info->pc);
 197
 198   /* wander down the instruction stream */
 199   examine_frame (pc, frame_info->saved_regs, frame_info->frame);
 200
 201 }
 202
 203 void
 204 z8k_push_dummy_frame ()
 205 {
 206   abort ();
 207 }
 208
 209 int
 210 gdb_print_insn_z8k (memaddr, info)
 211      bfd_vma memaddr;
 212      disassemble_info *info;
 213 {
 214   if (BIG)
 215     return print_insn_z8001 (memaddr, info);
 216   else
 217     return print_insn_z8002 (memaddr, info);
 218 }
 219
 220 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 221    is not the address of a valid instruction, the address of the next
 222    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 223    of the instruction.*/
 224
 225 CORE_ADDR
 226 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 227      CORE_ADDR addr;
 228      CORE_ADDR lim;
 229      short *pword1;
 230 {
 231   char buf[2];
 232   if (addr < lim + 8)
 233     {
 234       read_memory (addr, buf, 2);
 235       *pword1 = extract_signed_integer (buf, 2);
 236
 237       return addr + 2;
 238     }
 239   return 0;
 240 }
 241
 242 #if 0
 243 /* Put here the code to store, into a struct frame_saved_regs,
 244    the addresses of the saved registers of frame described by FRAME_INFO.
 245    This includes special registers such as pc and fp saved in special
 246    ways in the stack frame.  sp is even more special:
 247    the address we return for it IS the sp for the next frame.
 248
 249    We cache the result of doing this in the frame_cache_obstack, since
 250    it is fairly expensive.  */
 251
 252 void
 253 frame_find_saved_regs (fip, fsrp)
 254      struct frame_info *fip;
 255      struct frame_saved_regs *fsrp;
 256 {
 257   int locals;
 258   CORE_ADDR pc;
 259   CORE_ADDR adr;
 260   int i;
 261
 262   memset (fsrp, 0, sizeof *fsrp);
 263
 264   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 265
 266   {
 267     adr = FRAME_FP (fip) - locals;
 268     for (i = 0; i < 8; i++)
 269       {
 270         int word = read_memory_short (pc);
 271
 272         pc += 2;
 273         if (IS_PUSHL (word))
 274           {
 275             fsrp->regs[word & 0xf] = adr;
 276             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 277             adr -= 4;
 278           }
 279         else if (IS_PUSHW (word))
 280           {
 281             fsrp->regs[word & 0xf] = adr;
 282             adr -= 2;
 283           }
 284         else
 285           break;
 286       }
 287
 288   }
 289
 290   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 291   fsrp->regs[FP_REGNUM] = fip->frame;
 292
 293 }
 294 #endif
 295
 296 int
 297 saved_pc_after_call ()
 298 {
 299   return ADDR_BITS_REMOVE
 300     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 301 }
 302
 303
 304 void
 305 extract_return_value (type, regbuf, valbuf)
 306      struct type *type;
 307      char *regbuf;
 308      char *valbuf;
 309 {
 310   int b;
 311   int len = TYPE_LENGTH (type);
 312
 313   for (b = 0; b < len; b += 2)
 314     {
 315       int todo = len - b;
 316
 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
 331   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 332     write_register_bytes (REGISTER_BYTE (len / 2  + 2), valbuf + len, 2);
 333 }
 334
 335 void
 336 store_struct_return (addr, sp)
 337      CORE_ADDR addr;
 338      CORE_ADDR sp;
 339 {
 340   write_register (2, addr);
 341 }
 342
 343
 344 void
 345 print_register_hook (regno)
 346      int regno;
 347 {
 348   if ((regno & 1) == 0 && regno < 16)
 349     {
 350       unsigned short l[2];
 351
 352       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 353       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 354       printf_unfiltered ("\t");
 355       printf_unfiltered ("%04x%04x", l[0], l[1]);
 356     }
 357
 358   if ((regno & 3) == 0 && regno < 16)
 359     {
 360       unsigned short l[4];
 361
 362       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 363       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 364       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 365       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 366
 367       printf_unfiltered ("\t");
 368       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 369     }
 370   if (regno == 15)
 371     {
 372       unsigned short rval;
 373       int i;
 374
 375       read_relative_register_raw_bytes (regno, (char *) (&rval));
 376
 377       printf_unfiltered ("\n");
 378       for (i = 0; i < 10; i += 2)
 379         {
 380           printf_unfiltered ("(sp+%d=%04x)", i, read_memory_short (rval + i));
 381         }
 382     }
 383
 384 }
 385
 386 void
 387 z8k_pop_frame ()
 388 {
 389 }
 390
 391 struct cmd_list_element *setmemorylist;
 392
 393 void
 394 z8k_set_pointer_size (newsize)
 395      int newsize;
 396 {
 397   static int oldsize = 0;
 398
 399   if (oldsize != newsize)
 400     {
 401       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 402       oldsize = newsize;
 403       if (newsize == 32)
 404         {
 405           BIG = 1;
 406         }
 407       else
 408         {
 409           BIG = 0;
 410         }
 411       _initialize_gdbtypes ();
 412     }
 413 }
 414
 415 static void
 416 segmented_command (args, from_tty)
 417      char *args;
 418      int from_tty;
 419 {
 420   z8k_set_pointer_size (32);
 421 }
 422
 423 static void
 424 unsegmented_command (args, from_tty)
 425      char *args;
 426      int from_tty;
 427 {
 428   z8k_set_pointer_size (16);
 429 }
 430
 431 static void
 432 set_memory (args, from_tty)
 433      char *args;
 434      int from_tty;
 435 {
 436   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 437   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 438 }
 439
 440 void
 441 _initialize_z8ktdep ()
 442 {
 443   tm_print_insn = gdb_print_insn_z8k;
 444
 445   add_prefix_cmd ("memory", no_class, set_memory,
 446                   "set the memory model", &setmemorylist, "set memory ", 0,
 447                   &setlist);
 448   add_cmd ("segmented", class_support, segmented_command,
 449            "Set segmented memory model.", &setmemorylist);
 450   add_cmd ("unsegmented", class_support, unsegmented_command,
 451            "Set unsegmented memory model.", &setmemorylist);
 452
 453 }