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 int
  84 examine_frame (pc, regs, sp)
  85      CORE_ADDR pc;
  86      struct frame_saved_regs *regs;
  87      CORE_ADDR sp;
  88 {
  89   int w = read_memory_short (pc);
  90   int offset = 0;
  91   int regno;
  92
  93   for (regno = 0; regno < NUM_REGS; regno++)
  94     regs->regs[regno] = 0;
  95
  96   while (IS_PUSHW (w) || IS_PUSHL (w))
  97     {
  98       /* work out which register is being pushed to where */
  99       if (IS_PUSHL (w))
 100         {
 101           regs->regs[w & 0xf] = offset;
 102           regs->regs[(w & 0xf) + 1] = offset + 2;
 103           offset += 4;
 104         }
 105       else
 106         {
 107           regs->regs[w & 0xf] = offset;
 108           offset += 2;
 109         }
 110       pc += 2;
 111       w = read_memory_short (pc);
 112     }
 113
 114   if (IS_MOVE_FP (w))
 115     {
 116       /* We know the fp */
 117
 118     }
 119   else if (IS_SUB_SP (w))
 120     {
 121       /* Subtracting a value from the sp, so were in a function
 122        which needs stack space for locals, but has no fp.  We fake up
 123        the values as if we had an fp */
 124       regs->regs[FP_REGNUM] = sp;
 125     }
 126   else
 127     {
 128       /* This one didn't have an fp, we'll fake it up */
 129       regs->regs[SP_REGNUM] = sp;
 130     }
 131   /* stack pointer contains address of next frame */
 132   /*  regs->regs[fp_regnum()] = fp;*/
 133   regs->regs[SP_REGNUM] = sp;
 134   return pc;
 135 }
 136
 137 CORE_ADDR
 138 z8k_skip_prologue (start_pc)
 139      CORE_ADDR start_pc;
 140 {
 141   struct frame_saved_regs dummy;
 142
 143   return examine_frame (start_pc, &dummy, 0);
 144 }
 145
 146 CORE_ADDR
 147 z8k_addr_bits_remove (addr)
 148      CORE_ADDR addr;
 149 {
 150   return (addr & PTR_MASK);
 151 }
 152
 153 int
 154 read_memory_pointer (x)
 155      CORE_ADDR x;
 156 {
 157   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 158 }
 159
 160 CORE_ADDR
 161 frame_chain (thisframe)
 162      struct frame_info *thisframe;
 163 {
 164   if (thisframe->prev == 0)
 165     {
 166       /* This is the top of the stack, let's get the sp for real */
 167     }
 168   if (!inside_entry_file (thisframe->pc))
 169     {
 170       return read_memory_pointer (thisframe->frame);
 171     }
 172   return 0;
 173 }
 174
 175 void
 176 init_frame_pc ()
 177 {
 178   abort ();
 179 }
 180
 181 /* Put here the code to store, into a struct frame_saved_regs,
 182    the addresses of the saved registers of frame described by FRAME_INFO.
 183    This includes special registers such as pc and fp saved in special
 184    ways in the stack frame.  sp is even more special:
 185    the address we return for it IS the sp for the next frame.  */
 186
 187 void
 188 get_frame_saved_regs (frame_info, frame_saved_regs)
 189      struct frame_info *frame_info;
 190      struct frame_saved_regs *frame_saved_regs;
 191
 192 {
 193   CORE_ADDR pc;
 194   int w;
 195
 196   memset (frame_saved_regs, '\0', sizeof (*frame_saved_regs));
 197   pc = get_pc_function_start (frame_info->pc);
 198
 199 /* wander down the instruction stream */
 200   examine_frame (pc, frame_saved_regs, frame_info->frame);
 201
 202 }
 203
 204 void
 205 z8k_push_dummy_frame ()
 206 {
 207   abort ();
 208 }
 209
 210 int
 211 gdb_print_insn_z8k (memaddr, info)
 212      bfd_vma memaddr;
 213      disassemble_info *info;
 214 {
 215   if (BIG)
 216     return print_insn_z8001 (memaddr, info);
 217   else
 218     return print_insn_z8002 (memaddr, info);
 219 }
 220
 221 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 222    is not the address of a valid instruction, the address of the next
 223    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 224    of the instruction.*/
 225
 226 CORE_ADDR
 227 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 228      CORE_ADDR addr;
 229      CORE_ADDR lim;
 230      short *pword1;
 231 {
 232   char buf[2];
 233   if (addr < lim + 8)
 234     {
 235       read_memory (addr, buf, 2);
 236       *pword1 = extract_signed_integer (buf, 2);
 237
 238       return addr + 2;
 239     }
 240   return 0;
 241 }
 242
 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
 295 int
 296 saved_pc_after_call ()
 297 {
 298   return ADDR_BITS_REMOVE
 299     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 300 }
 301
 302
 303 void
 304 extract_return_value (type, regbuf, valbuf)
 305      struct type *type;
 306      char *regbuf;
 307      char *valbuf;
 308 {
 309   int b;
 310   int len = TYPE_LENGTH (type);
 311
 312   for (b = 0; b < len; b += 2)
 313     {
 314       int todo = len - b;
 315
 316       if (todo > 2)
 317         todo = 2;
 318       memcpy (valbuf + b, regbuf + b, todo);
 319     }
 320 }
 321
 322 void
 323 write_return_value (type, valbuf)
 324      struct type *type;
 325      char *valbuf;
 326 {
 327   int reg;
 328   int len;
 329
 330   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 331     write_register_bytes (REGISTER_BYTE (len / 2  + 2), valbuf + len, 2);
 332 }
 333
 334 void
 335 store_struct_return (addr, sp)
 336      CORE_ADDR addr;
 337      CORE_ADDR sp;
 338 {
 339   write_register (2, addr);
 340 }
 341
 342
 343 void
 344 print_register_hook (regno)
 345      int regno;
 346 {
 347   if ((regno & 1) == 0 && regno < 16)
 348     {
 349       unsigned short l[2];
 350
 351       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 352       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 353       printf_unfiltered ("\t");
 354       printf_unfiltered ("%04x%04x", l[0], l[1]);
 355     }
 356
 357   if ((regno & 3) == 0 && regno < 16)
 358     {
 359       unsigned short l[4];
 360
 361       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 362       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 363       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 364       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 365
 366       printf_unfiltered ("\t");
 367       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 368     }
 369   if (regno == 15)
 370     {
 371       unsigned short rval;
 372       int i;
 373
 374       read_relative_register_raw_bytes (regno, (char *) (&rval));
 375
 376       printf_unfiltered ("\n");
 377       for (i = 0; i < 10; i += 2)
 378         {
 379           printf_unfiltered ("(sp+%d=%04x)", i, read_memory_short (rval + i));
 380         }
 381     }
 382
 383 }
 384
 385 void
 386 z8k_pop_frame ()
 387 {
 388 }
 389
 390 struct cmd_list_element *setmemorylist;
 391
 392 void
 393 z8k_set_pointer_size (newsize)
 394      int newsize;
 395 {
 396   static int oldsize = 0;
 397
 398   if (oldsize != newsize)
 399     {
 400       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 401       oldsize = newsize;
 402       if (newsize == 32)
 403         {
 404           BIG = 1;
 405         }
 406       else
 407         {
 408           BIG = 0;
 409         }
 410       _initialize_gdbtypes ();
 411     }
 412 }
 413
 414 static void
 415 segmented_command (args, from_tty)
 416      char *args;
 417      int from_tty;
 418 {
 419   z8k_set_pointer_size (32);
 420 }
 421
 422 static void
 423 unsegmented_command (args, from_tty)
 424      char *args;
 425      int from_tty;
 426 {
 427   z8k_set_pointer_size (16);
 428 }
 429
 430 static void
 431 set_memory (args, from_tty)
 432      char *args;
 433      int from_tty;
 434 {
 435   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 436   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 437 }
 438
 439 void
 440 _initialize_z8ktdep ()
 441 {
 442   tm_print_insn = gdb_print_insn_z8k;
 443
 444   add_prefix_cmd ("memory", no_class, set_memory,
 445                   "set the memory model", &setmemorylist, "set memory ", 0,
 446                   &setlist);
 447   add_cmd ("segmented", class_support, segmented_command,
 448            "Set segmented memory model.", &setmemorylist);
 449   add_cmd ("unsegmented", class_support, unsegmented_command,
 450            "Set unsegmented memory model.", &setmemorylist);
 451
 452 }