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
  33 /* Return the saved PC from this frame.
  34
  35    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  36    just use the register SRP_REGNUM itself.  */
  37
  38 CORE_ADDR
  39 frame_saved_pc (frame)
  40      struct frame_info *frame;
  41 {
  42   return read_memory_pointer (frame->frame + (BIG ? 4 : 2));
  43 }
  44
  45 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  46 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  47 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  48 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  49 #define IS_SUB2_SP(x) (x==0x1b87)
  50 #define IS_MOVK_R5(x) (x==0x7905)
  51 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  52 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  53
  54 /* work out how much local space is on the stack and
  55    return the pc pointing to the first push */
  56
  57 static CORE_ADDR
  58 skip_adjust (pc, size)
  59      CORE_ADDR pc;
  60      int *size;
  61 {
  62   *size = 0;
  63
  64   if (IS_PUSH_FP (read_memory_short (pc))
  65       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  66     {
  67       /* This is a function with an explict frame pointer */
  68       pc += 4;
  69       *size += 2;               /* remember the frame pointer */
  70     }
  71
  72   /* remember any stack adjustment */
  73   if (IS_SUB_SP (read_memory_short (pc)))
  74     {
  75       *size += read_memory_short (pc + 2);
  76       pc += 4;
  77     }
  78   return pc;
  79 }
  80
  81 int
  82 examine_frame (pc, regs, sp)
  83      CORE_ADDR pc;
  84      struct frame_saved_regs *regs;
  85      CORE_ADDR sp;
  86 {
  87   int w = read_memory_short (pc);
  88   int offset = 0;
  89   int regno;
  90
  91   for (regno = 0; regno < NUM_REGS; regno++)
  92     regs->regs[regno] = 0;
  93
  94   while (IS_PUSHW (w) || IS_PUSHL (w))
  95     {
  96       /* work out which register is being pushed to where */
  97       if (IS_PUSHL (w))
  98         {
  99           regs->regs[w & 0xf] = offset;
 100           regs->regs[(w & 0xf) + 1] = offset + 2;
 101           offset += 4;
 102         }
 103       else
 104         {
 105           regs->regs[w & 0xf] = offset;
 106           offset += 2;
 107         }
 108       pc += 2;
 109       w = read_memory_short (pc);
 110     }
 111
 112   if (IS_MOVE_FP (w))
 113     {
 114       /* We know the fp */
 115
 116     }
 117   else if (IS_SUB_SP (w))
 118     {
 119       /* Subtracting a value from the sp, so were in a function
 120        which needs stack space for locals, but has no fp.  We fake up
 121        the values as if we had an fp */
 122       regs->regs[FP_REGNUM] = sp;
 123     }
 124   else
 125     {
 126       /* This one didn't have an fp, we'll fake it up */
 127       regs->regs[SP_REGNUM] = sp;
 128     }
 129   /* stack pointer contains address of next frame */
 130   /*  regs->regs[fp_regnum()] = fp;*/
 131   regs->regs[SP_REGNUM] = sp;
 132   return pc;
 133 }
 134
 135 CORE_ADDR
 136 z8k_skip_prologue (start_pc)
 137      CORE_ADDR start_pc;
 138 {
 139   struct frame_saved_regs dummy;
 140
 141   return examine_frame (start_pc, &dummy, 0);
 142 }
 143
 144 CORE_ADDR
 145 addr_bits_remove (x)
 146      CORE_ADDR x;
 147 {
 148   return x & PTR_MASK;
 149 }
 150
 151 int
 152 read_memory_pointer (x)
 153      CORE_ADDR x;
 154 {
 155   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 156 }
 157
 158 CORE_ADDR
 159 frame_chain (thisframe)
 160      struct frame_info *thisframe;
 161 {
 162   if (thisframe->prev == 0)
 163     {
 164       /* This is the top of the stack, let's get the sp for real */
 165     }
 166   if (!inside_entry_file (thisframe->pc))
 167     {
 168       return read_memory_pointer (thisframe->frame);
 169     }
 170   return 0;
 171 }
 172
 173 init_frame_pc ()
 174 {
 175   abort ();
 176 }
 177
 178 /* Put here the code to store, into a struct frame_saved_regs,
 179    the addresses of the saved registers of frame described by FRAME_INFO.
 180    This includes special registers such as pc and fp saved in special
 181    ways in the stack frame.  sp is even more special:
 182    the address we return for it IS the sp for the next frame.  */
 183
 184 void
 185 get_frame_saved_regs (frame_info, frame_saved_regs)
 186      struct frame_info *frame_info;
 187      struct frame_saved_regs *frame_saved_regs;
 188
 189 {
 190   CORE_ADDR pc;
 191   int w;
 192
 193   memset (frame_saved_regs, '\0', sizeof (*frame_saved_regs));
 194   pc = get_pc_function_start (frame_info->pc);
 195
 196 /* wander down the instruction stream */
 197   examine_frame (pc, frame_saved_regs, frame_info->frame);
 198
 199 }
 200
 201 void
 202 z8k_push_dummy_frame ()
 203 {
 204   abort ();
 205 }
 206
 207 int
 208 gdb_print_insn_z8k (memaddr, info)
 209      bfd_vma memaddr;
 210      disassemble_info *info;
 211 {
 212   if (BIG)
 213     return print_insn_z8001 (memaddr, info);
 214   else
 215     return print_insn_z8002 (memaddr, info);
 216 }
 217
 218 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 219    is not the address of a valid instruction, the address of the next
 220    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 221    of the instruction.*/
 222
 223 CORE_ADDR
 224 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 225      CORE_ADDR addr;
 226      CORE_ADDR lim;
 227      short *pword1;
 228 {
 229   char buf[2];
 230   if (addr < lim + 8)
 231     {
 232       read_memory (addr, buf, 2);
 233       *pword1 = extract_signed_integer (buf, 2);
 234
 235       return addr + 2;
 236     }
 237   return 0;
 238 }
 239
 240 /* Put here the code to store, into a struct frame_saved_regs,
 241    the addresses of the saved registers of frame described by FRAME_INFO.
 242    This includes special registers such as pc and fp saved in special
 243    ways in the stack frame.  sp is even more special:
 244    the address we return for it IS the sp for the next frame.
 245
 246    We cache the result of doing this in the frame_cache_obstack, since
 247    it is fairly expensive.  */
 248
 249 void
 250 frame_find_saved_regs (fip, fsrp)
 251      struct frame_info *fip;
 252      struct frame_saved_regs *fsrp;
 253 {
 254   int locals;
 255   CORE_ADDR pc;
 256   CORE_ADDR adr;
 257   int i;
 258
 259   memset (fsrp, 0, sizeof *fsrp);
 260
 261   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 262
 263   {
 264     adr = FRAME_FP (fip) - locals;
 265     for (i = 0; i < 8; i++)
 266       {
 267         int word = read_memory_short (pc);
 268
 269         pc += 2;
 270         if (IS_PUSHL (word))
 271           {
 272             fsrp->regs[word & 0xf] = adr;
 273             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 274             adr -= 4;
 275           }
 276         else if (IS_PUSHW (word))
 277           {
 278             fsrp->regs[word & 0xf] = adr;
 279             adr -= 2;
 280           }
 281         else
 282           break;
 283       }
 284
 285   }
 286
 287   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 288   fsrp->regs[FP_REGNUM] = fip->frame;
 289
 290 }
 291
 292 int
 293 saved_pc_after_call ()
 294 {
 295   return addr_bits_remove
 296     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 297 }
 298
 299
 300 extract_return_value (type, regbuf, valbuf)
 301      struct type *type;
 302      char *regbuf;
 303      char *valbuf;
 304 {
 305   int b;
 306   int len = TYPE_LENGTH (type);
 307
 308   for (b = 0; b < len; b += 2)
 309     {
 310       int todo = len - b;
 311
 312       if (todo > 2)
 313         todo = 2;
 314       memcpy (valbuf + b, regbuf + b, todo);
 315     }
 316 }
 317
 318 void
 319 write_return_value (type, valbuf)
 320      struct type *type;
 321      char *valbuf;
 322 {
 323   int reg;
 324   int len;
 325
 326   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 327     write_register_bytes (REGISTER_BYTE (len / 2  + 2), valbuf + len, 2);
 328 }
 329
 330 void
 331 store_struct_return (addr, sp)
 332      CORE_ADDR addr;
 333      CORE_ADDR sp;
 334 {
 335   write_register (2, addr);
 336 }
 337
 338
 339 void
 340 print_register_hook (regno)
 341      int regno;
 342 {
 343   if ((regno & 1) == 0 && regno < 16)
 344     {
 345       unsigned short l[2];
 346
 347       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 348       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 349       printf_unfiltered ("\t");
 350       printf_unfiltered ("%04x%04x", l[0], l[1]);
 351     }
 352
 353   if ((regno & 3) == 0 && regno < 16)
 354     {
 355       unsigned short l[4];
 356
 357       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 358       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 359       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 360       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 361
 362       printf_unfiltered ("\t");
 363       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 364     }
 365   if (regno == 15)
 366     {
 367       unsigned short rval;
 368       int i;
 369
 370       read_relative_register_raw_bytes (regno, (char *) (&rval));
 371
 372       printf_unfiltered ("\n");
 373       for (i = 0; i < 10; i += 2)
 374         {
 375           printf_unfiltered ("(sp+%d=%04x)", i, read_memory_short (rval + i));
 376         }
 377     }
 378
 379 }
 380
 381 void
 382 z8k_pop_frame ()
 383 {
 384 }
 385
 386 struct cmd_list_element *setmemorylist;
 387
 388 void
 389 z8k_set_pointer_size (newsize)
 390      int newsize;
 391 {
 392   static int oldsize = 0;
 393
 394   if (oldsize != newsize)
 395     {
 396       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 397       oldsize = newsize;
 398       if (newsize == 32)
 399         {
 400           BIG = 1;
 401         }
 402       else
 403         {
 404           BIG = 0;
 405         }
 406       _initialize_gdbtypes ();
 407     }
 408 }
 409
 410 static void
 411 segmented_command (args, from_tty)
 412      char *args;
 413      int from_tty;
 414 {
 415   z8k_set_pointer_size (32);
 416 }
 417
 418 static void
 419 unsegmented_command (args, from_tty)
 420      char *args;
 421      int from_tty;
 422 {
 423   z8k_set_pointer_size (16);
 424 }
 425
 426 static void
 427 set_memory (args, from_tty)
 428      char *args;
 429      int from_tty;
 430 {
 431   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 432   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 433 }
 434
 435 void
 436 _initialize_z8ktdep ()
 437 {
 438   tm_print_insn = gdb_print_insn_z8k;
 439
 440   add_prefix_cmd ("memory", no_class, set_memory,
 441                   "set the memory model", &setmemorylist, "set memory ", 0,
 442                   &setlist);
 443   add_cmd ("segmented", class_support, segmented_command,
 444            "Set segmented memory model.", &setmemorylist);
 445   add_cmd ("unsegmented", class_support, unsegmented_command,
 446            "Set unsegmented memory model.", &setmemorylist);
 447
 448 }