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 /* Return the saved PC from this frame.
  35
  36    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  37    just use the register SRP_REGNUM itself.  */
  38
  39 CORE_ADDR
  40 frame_saved_pc (frame)
  41      struct frame_info *frame;
  42 {
  43   return read_memory_pointer (frame->frame + (BIG ? 4 : 2));
  44 }
  45
  46 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  47 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  48 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  49 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  50 #define IS_SUB2_SP(x) (x==0x1b87)
  51 #define IS_MOVK_R5(x) (x==0x7905)
  52 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  53 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  54
  55 /* work out how much local space is on the stack and
  56    return the pc pointing to the first push */
  57
  58 static CORE_ADDR
  59 skip_adjust (pc, size)
  60      CORE_ADDR pc;
  61      int *size;
  62 {
  63   *size = 0;
  64
  65   if (IS_PUSH_FP (read_memory_short (pc))
  66       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  67     {
  68       /* This is a function with an explict frame pointer */
  69       pc += 4;
  70       *size += 2;               /* remember the frame pointer */
  71     }
  72
  73   /* remember any stack adjustment */
  74   if (IS_SUB_SP (read_memory_short (pc)))
  75     {
  76       *size += read_memory_short (pc + 2);
  77       pc += 4;
  78     }
  79   return pc;
  80 }
  81
  82 int
  83 examine_frame (pc, regs, sp)
  84      CORE_ADDR pc;
  85      struct frame_saved_regs *regs;
  86      CORE_ADDR sp;
  87 {
  88   int w = read_memory_short (pc);
  89   int offset = 0;
  90   int regno;
  91
  92   for (regno = 0; regno < NUM_REGS; regno++)
  93     regs->regs[regno] = 0;
  94
  95   while (IS_PUSHW (w) || IS_PUSHL (w))
  96     {
  97       /* work out which register is being pushed to where */
  98       if (IS_PUSHL (w))
  99         {
 100           regs->regs[w & 0xf] = offset;
 101           regs->regs[(w & 0xf) + 1] = offset + 2;
 102           offset += 4;
 103         }
 104       else
 105         {
 106           regs->regs[w & 0xf] = offset;
 107           offset += 2;
 108         }
 109       pc += 2;
 110       w = read_memory_short (pc);
 111     }
 112
 113   if (IS_MOVE_FP (w))
 114     {
 115       /* We know the fp */
 116
 117     }
 118   else if (IS_SUB_SP (w))
 119     {
 120       /* Subtracting a value from the sp, so were in a function
 121        which needs stack space for locals, but has no fp.  We fake up
 122        the values as if we had an fp */
 123       regs->regs[FP_REGNUM] = sp;
 124     }
 125   else
 126     {
 127       /* This one didn't have an fp, we'll fake it up */
 128       regs->regs[SP_REGNUM] = sp;
 129     }
 130   /* stack pointer contains address of next frame */
 131   /*  regs->regs[fp_regnum()] = fp;*/
 132   regs->regs[SP_REGNUM] = sp;
 133   return pc;
 134 }
 135
 136 CORE_ADDR
 137 z8k_skip_prologue (start_pc)
 138      CORE_ADDR start_pc;
 139 {
 140   struct frame_saved_regs dummy;
 141
 142   return examine_frame (start_pc, &dummy, 0);
 143 }
 144
 145 CORE_ADDR
 146 addr_bits_remove (x)
 147      CORE_ADDR x;
 148 {
 149   return x & PTR_MASK;
 150 }
 151
 152 int
 153 read_memory_pointer (x)
 154      CORE_ADDR x;
 155 {
 156   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 157 }
 158
 159 CORE_ADDR
 160 frame_chain (thisframe)
 161      struct frame_info *thisframe;
 162 {
 163   if (thisframe->prev == 0)
 164     {
 165       /* This is the top of the stack, let's get the sp for real */
 166     }
 167   if (!inside_entry_file (thisframe->pc))
 168     {
 169       return read_memory_pointer (thisframe->frame);
 170     }
 171   return 0;
 172 }
 173
 174 init_frame_pc ()
 175 {
 176   abort ();
 177 }
 178
 179 /* Put here the code to store, into a struct frame_saved_regs,
 180    the addresses of the saved registers of frame described by FRAME_INFO.
 181    This includes special registers such as pc and fp saved in special
 182    ways in the stack frame.  sp is even more special:
 183    the address we return for it IS the sp for the next frame.  */
 184
 185 void
 186 get_frame_saved_regs (frame_info, frame_saved_regs)
 187      struct frame_info *frame_info;
 188      struct frame_saved_regs *frame_saved_regs;
 189
 190 {
 191   CORE_ADDR pc;
 192   int w;
 193
 194   memset (frame_saved_regs, '\0', sizeof (*frame_saved_regs));
 195   pc = get_pc_function_start (frame_info->pc);
 196
 197 /* wander down the instruction stream */
 198   examine_frame (pc, frame_saved_regs, frame_info->frame);
 199
 200 }
 201
 202 void
 203 z8k_push_dummy_frame ()
 204 {
 205   abort ();
 206 }
 207
 208 int
 209 gdb_print_insn_z8k (memaddr, info)
 210      bfd_vma memaddr;
 211      disassemble_info *info;
 212 {
 213   if (BIG)
 214     return print_insn_z8001 (memaddr, info);
 215   else
 216     return print_insn_z8002 (memaddr, info);
 217 }
 218
 219 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 220    is not the address of a valid instruction, the address of the next
 221    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 222    of the instruction.*/
 223
 224 CORE_ADDR
 225 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 226      CORE_ADDR addr;
 227      CORE_ADDR lim;
 228      short *pword1;
 229 {
 230   char buf[2];
 231   if (addr < lim + 8)
 232     {
 233       read_memory (addr, buf, 2);
 234       *pword1 = extract_signed_integer (buf, 2);
 235
 236       return addr + 2;
 237     }
 238   return 0;
 239 }
 240
 241 /* Put here the code to store, into a struct frame_saved_regs,
 242    the addresses of the saved registers of frame described by FRAME_INFO.
 243    This includes special registers such as pc and fp saved in special
 244    ways in the stack frame.  sp is even more special:
 245    the address we return for it IS the sp for the next frame.
 246
 247    We cache the result of doing this in the frame_cache_obstack, since
 248    it is fairly expensive.  */
 249
 250 void
 251 frame_find_saved_regs (fip, fsrp)
 252      struct frame_info *fip;
 253      struct frame_saved_regs *fsrp;
 254 {
 255   int locals;
 256   CORE_ADDR pc;
 257   CORE_ADDR adr;
 258   int i;
 259
 260   memset (fsrp, 0, sizeof *fsrp);
 261
 262   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 263
 264   {
 265     adr = FRAME_FP (fip) - locals;
 266     for (i = 0; i < 8; i++)
 267       {
 268         int word = read_memory_short (pc);
 269
 270         pc += 2;
 271         if (IS_PUSHL (word))
 272           {
 273             fsrp->regs[word & 0xf] = adr;
 274             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 275             adr -= 4;
 276           }
 277         else if (IS_PUSHW (word))
 278           {
 279             fsrp->regs[word & 0xf] = adr;
 280             adr -= 2;
 281           }
 282         else
 283           break;
 284       }
 285
 286   }
 287
 288   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 289   fsrp->regs[FP_REGNUM] = fip->frame;
 290
 291 }
 292
 293 int
 294 saved_pc_after_call ()
 295 {
 296   return addr_bits_remove
 297     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 298 }
 299
 300
 301 extract_return_value (type, regbuf, valbuf)
 302      struct type *type;
 303      char *regbuf;
 304      char *valbuf;
 305 {
 306   int b;
 307   int len = TYPE_LENGTH (type);
 308
 309   for (b = 0; b < len; b += 2)
 310     {
 311       int todo = len - b;
 312
 313       if (todo > 2)
 314         todo = 2;
 315       memcpy (valbuf + b, regbuf + b, todo);
 316     }
 317 }
 318
 319 void
 320 write_return_value (type, valbuf)
 321      struct type *type;
 322      char *valbuf;
 323 {
 324   int reg;
 325   int len;
 326
 327   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 328     write_register_bytes (REGISTER_BYTE (len / 2  + 2), valbuf + len, 2);
 329 }
 330
 331 void
 332 store_struct_return (addr, sp)
 333      CORE_ADDR addr;
 334      CORE_ADDR sp;
 335 {
 336   write_register (2, addr);
 337 }
 338
 339
 340 void
 341 print_register_hook (regno)
 342      int regno;
 343 {
 344   if ((regno & 1) == 0 && regno < 16)
 345     {
 346       unsigned short l[2];
 347
 348       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 349       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 350       printf_unfiltered ("\t");
 351       printf_unfiltered ("%04x%04x", l[0], l[1]);
 352     }
 353
 354   if ((regno & 3) == 0 && regno < 16)
 355     {
 356       unsigned short l[4];
 357
 358       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 359       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 360       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 361       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 362
 363       printf_unfiltered ("\t");
 364       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 365     }
 366   if (regno == 15)
 367     {
 368       unsigned short rval;
 369       int i;
 370
 371       read_relative_register_raw_bytes (regno, (char *) (&rval));
 372
 373       printf_unfiltered ("\n");
 374       for (i = 0; i < 10; i += 2)
 375         {
 376           printf_unfiltered ("(sp+%d=%04x)", i, read_memory_short (rval + i));
 377         }
 378     }
 379
 380 }
 381
 382 void
 383 z8k_pop_frame ()
 384 {
 385 }
 386
 387 struct cmd_list_element *setmemorylist;
 388
 389 void
 390 z8k_set_pointer_size (newsize)
 391      int newsize;
 392 {
 393   static int oldsize = 0;
 394
 395   if (oldsize != newsize)
 396     {
 397       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 398       oldsize = newsize;
 399       if (newsize == 32)
 400         {
 401           BIG = 1;
 402         }
 403       else
 404         {
 405           BIG = 0;
 406         }
 407       _initialize_gdbtypes ();
 408     }
 409 }
 410
 411 static void
 412 segmented_command (args, from_tty)
 413      char *args;
 414      int from_tty;
 415 {
 416   z8k_set_pointer_size (32);
 417 }
 418
 419 static void
 420 unsegmented_command (args, from_tty)
 421      char *args;
 422      int from_tty;
 423 {
 424   z8k_set_pointer_size (16);
 425 }
 426
 427 static void
 428 set_memory (args, from_tty)
 429      char *args;
 430      int from_tty;
 431 {
 432   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 433   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 434 }
 435
 436 void
 437 _initialize_z8ktdep ()
 438 {
 439   tm_print_insn = gdb_print_insn_z8k;
 440
 441   add_prefix_cmd ("memory", no_class, set_memory,
 442                   "set the memory model", &setmemorylist, "set memory ", 0,
 443                   &setlist);
 444   add_cmd ("segmented", class_support, segmented_command,
 445            "Set segmented memory model.", &setmemorylist);
 446   add_cmd ("unsegmented", class_support, unsegmented_command,
 447            "Set unsegmented memory model.", &setmemorylist);
 448
 449 }