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,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 /*
  22    Contributed by Steve Chamberlain
  23    sac@cygnus.com
  24  */
  25
  26 #include "defs.h"
  27 #include "frame.h"
  28 #include "obstack.h"
  29 #include "symtab.h"
  30 #include "gdbcmd.h"
  31 #include "gdbtypes.h"
  32 #include "dis-asm.h"
  33 #include "gdbcore.h"
  34
  35 #include "value.h" /* For read_register() */
  36
  37
  38 static int read_memory_pointer (CORE_ADDR x);
  39
  40 /* Return the saved PC from this frame.
  41
  42    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  43    just use the register SRP_REGNUM itself.  */
  44
  45 CORE_ADDR
  46 z8k_frame_saved_pc (frame)
  47      struct frame_info *frame;
  48 {
  49   return read_memory_pointer (frame->frame + (BIG ? 4 : 2));
  50 }
  51
  52 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  53 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  54 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  55 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  56 #define IS_SUB2_SP(x) (x==0x1b87)
  57 #define IS_MOVK_R5(x) (x==0x7905)
  58 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  59 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  60
  61 /* work out how much local space is on the stack and
  62    return the pc pointing to the first push */
  63
  64 static CORE_ADDR
  65 skip_adjust (pc, size)
  66      CORE_ADDR pc;
  67      int *size;
  68 {
  69   *size = 0;
  70
  71   if (IS_PUSH_FP (read_memory_short (pc))
  72       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  73     {
  74       /* This is a function with an explict frame pointer */
  75       pc += 4;
  76       *size += 2;               /* remember the frame pointer */
  77     }
  78
  79   /* remember any stack adjustment */
  80   if (IS_SUB_SP (read_memory_short (pc)))
  81     {
  82       *size += read_memory_short (pc + 2);
  83       pc += 4;
  84     }
  85   return pc;
  86 }
  87
  88 static CORE_ADDR examine_frame PARAMS ((CORE_ADDR, CORE_ADDR * regs, CORE_ADDR));
  89 static CORE_ADDR
  90 examine_frame (pc, regs, sp)
  91      CORE_ADDR pc;
  92      CORE_ADDR *regs;
  93      CORE_ADDR sp;
  94 {
  95   int w = read_memory_short (pc);
  96   int offset = 0;
  97   int regno;
  98
  99   for (regno = 0; regno < NUM_REGS; regno++)
 100     regs[regno] = 0;
 101
 102   while (IS_PUSHW (w) || IS_PUSHL (w))
 103     {
 104       /* work out which register is being pushed to where */
 105       if (IS_PUSHL (w))
 106         {
 107           regs[w & 0xf] = offset;
 108           regs[(w & 0xf) + 1] = offset + 2;
 109           offset += 4;
 110         }
 111       else
 112         {
 113           regs[w & 0xf] = offset;
 114           offset += 2;
 115         }
 116       pc += 2;
 117       w = read_memory_short (pc);
 118     }
 119
 120   if (IS_MOVE_FP (w))
 121     {
 122       /* We know the fp */
 123
 124     }
 125   else if (IS_SUB_SP (w))
 126     {
 127       /* Subtracting a value from the sp, so were in a function
 128          which needs stack space for locals, but has no fp.  We fake up
 129          the values as if we had an fp */
 130       regs[FP_REGNUM] = sp;
 131     }
 132   else
 133     {
 134       /* This one didn't have an fp, we'll fake it up */
 135       regs[SP_REGNUM] = sp;
 136     }
 137   /* stack pointer contains address of next frame */
 138   /*  regs[fp_regnum()] = fp; */
 139   regs[SP_REGNUM] = sp;
 140   return pc;
 141 }
 142
 143 CORE_ADDR
 144 z8k_skip_prologue (start_pc)
 145      CORE_ADDR start_pc;
 146 {
 147   CORE_ADDR dummy[NUM_REGS];
 148
 149   return examine_frame (start_pc, dummy, 0);
 150 }
 151
 152 CORE_ADDR
 153 z8k_addr_bits_remove (addr)
 154      CORE_ADDR addr;
 155 {
 156   return (addr & PTR_MASK);
 157 }
 158
 159 static int
 160 read_memory_pointer (CORE_ADDR x)
 161 {
 162   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 163 }
 164
 165 CORE_ADDR
 166 z8k_frame_chain (thisframe)
 167      struct frame_info *thisframe;
 168 {
 169   if (thisframe->prev == 0)
 170     {
 171       /* This is the top of the stack, let's get the sp for real */
 172     }
 173   if (!inside_entry_file (thisframe->pc))
 174     {
 175       return read_memory_pointer (thisframe->frame);
 176     }
 177   return 0;
 178 }
 179
 180 void
 181 init_frame_pc ()
 182 {
 183   abort ();
 184 }
 185
 186 /* Put here the code to store, into a struct frame_saved_regs,
 187    the addresses of the saved registers of frame described by FRAME_INFO.
 188    This includes special registers such as pc and fp saved in special
 189    ways in the stack frame.  sp is even more special:
 190    the address we return for it IS the sp for the next frame.  */
 191
 192 void
 193 z8k_frame_init_saved_regs (frame_info)
 194      struct frame_info *frame_info;
 195 {
 196   CORE_ADDR pc;
 197   int w;
 198
 199   frame_saved_regs_zalloc (frame_info);
 200   pc = get_pc_function_start (frame_info->pc);
 201
 202   /* wander down the instruction stream */
 203   examine_frame (pc, frame_info->saved_regs, frame_info->frame);
 204
 205 }
 206
 207 void
 208 z8k_push_dummy_frame ()
 209 {
 210   abort ();
 211 }
 212
 213 int
 214 gdb_print_insn_z8k (memaddr, info)
 215      bfd_vma memaddr;
 216      disassemble_info *info;
 217 {
 218   if (BIG)
 219     return print_insn_z8001 (memaddr, info);
 220   else
 221     return print_insn_z8002 (memaddr, info);
 222 }
 223
 224 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 225    is not the address of a valid instruction, the address of the next
 226    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 227    of the instruction. */
 228
 229 CORE_ADDR
 230 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 231      CORE_ADDR addr;
 232      CORE_ADDR lim;
 233      short *pword1;
 234 {
 235   char buf[2];
 236   if (addr < lim + 8)
 237     {
 238       read_memory (addr, buf, 2);
 239       *pword1 = extract_signed_integer (buf, 2);
 240
 241       return addr + 2;
 242     }
 243   return 0;
 244 }
 245
 246 #if 0
 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 = FRAME_FP (fip) - 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 #endif
 299
 300 int
 301 z8k_saved_pc_after_call (struct frame_info *frame)
 302 {
 303   return ADDR_BITS_REMOVE
 304     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 305 }
 306
 307
 308 void
 309 extract_return_value (type, regbuf, valbuf)
 310      struct type *type;
 311      char *regbuf;
 312      char *valbuf;
 313 {
 314   int b;
 315   int len = TYPE_LENGTH (type);
 316
 317   for (b = 0; b < len; b += 2)
 318     {
 319       int todo = len - b;
 320
 321       if (todo > 2)
 322         todo = 2;
 323       memcpy (valbuf + b, regbuf + b, todo);
 324     }
 325 }
 326
 327 void
 328 write_return_value (type, valbuf)
 329      struct type *type;
 330      char *valbuf;
 331 {
 332   int reg;
 333   int len;
 334
 335   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 336     write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
 337 }
 338
 339 void
 340 store_struct_return (addr, sp)
 341      CORE_ADDR addr;
 342      CORE_ADDR sp;
 343 {
 344   write_register (2, addr);
 345 }
 346
 347
 348 void
 349 z8k_print_register_hook (regno)
 350      int regno;
 351 {
 352   if ((regno & 1) == 0 && regno < 16)
 353     {
 354       unsigned short l[2];
 355
 356       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 357       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 358       printf_unfiltered ("\t");
 359       printf_unfiltered ("%04x%04x", l[0], l[1]);
 360     }
 361
 362   if ((regno & 3) == 0 && regno < 16)
 363     {
 364       unsigned short l[4];
 365
 366       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 367       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 368       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 369       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 370
 371       printf_unfiltered ("\t");
 372       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 373     }
 374   if (regno == 15)
 375     {
 376       unsigned short rval;
 377       int i;
 378
 379       read_relative_register_raw_bytes (regno, (char *) (&rval));
 380
 381       printf_unfiltered ("\n");
 382       for (i = 0; i < 10; i += 2)
 383         {
 384           printf_unfiltered ("(sp+%d=%04x)", i,
 385                              (unsigned int)read_memory_short (rval + i));
 386         }
 387     }
 388
 389 }
 390
 391 void
 392 z8k_pop_frame ()
 393 {
 394 }
 395
 396 struct cmd_list_element *setmemorylist;
 397
 398 void
 399 z8k_set_pointer_size (newsize)
 400      int newsize;
 401 {
 402   static int oldsize = 0;
 403
 404   if (oldsize != newsize)
 405     {
 406       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 407       oldsize = newsize;
 408       if (newsize == 32)
 409         {
 410           BIG = 1;
 411         }
 412       else
 413         {
 414           BIG = 0;
 415         }
 416       /* FIXME: This code should be using the GDBARCH framework to
 417          handle changed type sizes.  If this problem is ever fixed
 418          (the direct reference to _initialize_gdbtypes() below
 419          eliminated) then Makefile.in should be updated so that
 420          z8k-tdep.c is again compiled with -Werror. */
 421       _initialize_gdbtypes ();
 422     }
 423 }
 424
 425 static void
 426 segmented_command (args, from_tty)
 427      char *args;
 428      int from_tty;
 429 {
 430   z8k_set_pointer_size (32);
 431 }
 432
 433 static void
 434 unsegmented_command (args, from_tty)
 435      char *args;
 436      int from_tty;
 437 {
 438   z8k_set_pointer_size (16);
 439 }
 440
 441 static void
 442 set_memory (args, from_tty)
 443      char *args;
 444      int from_tty;
 445 {
 446   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 447   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 448 }
 449
 450 void
 451 _initialize_z8ktdep ()
 452 {
 453   tm_print_insn = gdb_print_insn_z8k;
 454
 455   add_prefix_cmd ("memory", no_class, set_memory,
 456                   "set the memory model", &setmemorylist, "set memory ", 0,
 457                   &setlist);
 458   add_cmd ("segmented", class_support, segmented_command,
 459            "Set segmented memory model.", &setmemorylist);
 460   add_cmd ("unsegmented", class_support, unsegmented_command,
 461            "Set unsegmented memory model.", &setmemorylist);
 462
 463 }