gdb/z8k-tdep.c

   1 /* Target-machine dependent code for Zilog Z8000, for GDB.
   2    Copyright (C) 1992, 1993, 1994, 2001 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 #include "regcache.h"
  35
  36 #include "value.h" /* For read_register() */
  37
  38
  39 static int read_memory_pointer (CORE_ADDR x);
  40
  41 /* Return the saved PC from this frame.
  42
  43    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  44    just use the register SRP_REGNUM itself.  */
  45
  46 CORE_ADDR
  47 z8k_frame_saved_pc (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 (CORE_ADDR pc, int *size)
  66 {
  67   *size = 0;
  68
  69   if (IS_PUSH_FP (read_memory_short (pc))
  70       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  71     {
  72       /* This is a function with an explict frame pointer */
  73       pc += 4;
  74       *size += 2;               /* remember the frame pointer */
  75     }
  76
  77   /* remember any stack adjustment */
  78   if (IS_SUB_SP (read_memory_short (pc)))
  79     {
  80       *size += read_memory_short (pc + 2);
  81       pc += 4;
  82     }
  83   return pc;
  84 }
  85
  86 static CORE_ADDR examine_frame (CORE_ADDR, CORE_ADDR * regs, CORE_ADDR);
  87 static CORE_ADDR
  88 examine_frame (CORE_ADDR pc, CORE_ADDR *regs, 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 (CORE_ADDR start_pc)
 140 {
 141   CORE_ADDR dummy[NUM_REGS];
 142
 143   return examine_frame (start_pc, dummy, 0);
 144 }
 145
 146 CORE_ADDR
 147 z8k_addr_bits_remove (CORE_ADDR addr)
 148 {
 149   return (addr & PTR_MASK);
 150 }
 151
 152 static int
 153 read_memory_pointer (CORE_ADDR x)
 154 {
 155   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 156 }
 157
 158 CORE_ADDR
 159 z8k_frame_chain (struct frame_info *thisframe)
 160 {
 161   if (thisframe->prev == 0)
 162     {
 163       /* This is the top of the stack, let's get the sp for real */
 164     }
 165   if (!inside_entry_file (thisframe->pc))
 166     {
 167       return read_memory_pointer (thisframe->frame);
 168     }
 169   return 0;
 170 }
 171
 172 void
 173 init_frame_pc (void)
 174 {
 175   internal_error (__FILE__, __LINE__, "failed internal consistency check");
 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 z8k_frame_init_saved_regs (struct frame_info *frame_info)
 186 {
 187   CORE_ADDR pc;
 188   int w;
 189
 190   frame_saved_regs_zalloc (frame_info);
 191   pc = get_pc_function_start (frame_info->pc);
 192
 193   /* wander down the instruction stream */
 194   examine_frame (pc, frame_info->saved_regs, frame_info->frame);
 195
 196 }
 197
 198 void
 199 z8k_push_dummy_frame (void)
 200 {
 201   internal_error (__FILE__, __LINE__, "failed internal consistency check");
 202 }
 203
 204 int
 205 gdb_print_insn_z8k (bfd_vma memaddr, disassemble_info *info)
 206 {
 207   if (BIG)
 208     return print_insn_z8001 (memaddr, info);
 209   else
 210     return print_insn_z8002 (memaddr, info);
 211 }
 212
 213 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 214    is not the address of a valid instruction, the address of the next
 215    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 216    of the instruction. */
 217
 218 CORE_ADDR
 219 NEXT_PROLOGUE_INSN (CORE_ADDR addr, CORE_ADDR lim, short *pword1)
 220 {
 221   char buf[2];
 222   if (addr < lim + 8)
 223     {
 224       read_memory (addr, buf, 2);
 225       *pword1 = extract_signed_integer (buf, 2);
 226
 227       return addr + 2;
 228     }
 229   return 0;
 230 }
 231
 232 #if 0
 233 /* Put here the code to store, into a struct frame_saved_regs,
 234    the addresses of the saved registers of frame described by FRAME_INFO.
 235    This includes special registers such as pc and fp saved in special
 236    ways in the stack frame.  sp is even more special:
 237    the address we return for it IS the sp for the next frame.
 238
 239    We cache the result of doing this in the frame_cache_obstack, since
 240    it is fairly expensive.  */
 241
 242 void
 243 frame_find_saved_regs (struct frame_info *fip, struct frame_saved_regs *fsrp)
 244 {
 245   int locals;
 246   CORE_ADDR pc;
 247   CORE_ADDR adr;
 248   int i;
 249
 250   memset (fsrp, 0, sizeof *fsrp);
 251
 252   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 253
 254   {
 255     adr = FRAME_FP (fip) - locals;
 256     for (i = 0; i < 8; i++)
 257       {
 258         int word = read_memory_short (pc);
 259
 260         pc += 2;
 261         if (IS_PUSHL (word))
 262           {
 263             fsrp->regs[word & 0xf] = adr;
 264             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 265             adr -= 4;
 266           }
 267         else if (IS_PUSHW (word))
 268           {
 269             fsrp->regs[word & 0xf] = adr;
 270             adr -= 2;
 271           }
 272         else
 273           break;
 274       }
 275
 276   }
 277
 278   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 279   fsrp->regs[FP_REGNUM] = fip->frame;
 280
 281 }
 282 #endif
 283
 284 int
 285 z8k_saved_pc_after_call (struct frame_info *frame)
 286 {
 287   return ADDR_BITS_REMOVE
 288     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 289 }
 290
 291
 292 void
 293 extract_return_value (struct type *type, char *regbuf, char *valbuf)
 294 {
 295   int b;
 296   int len = TYPE_LENGTH (type);
 297
 298   for (b = 0; b < len; b += 2)
 299     {
 300       int todo = len - b;
 301
 302       if (todo > 2)
 303         todo = 2;
 304       memcpy (valbuf + b, regbuf + b, todo);
 305     }
 306 }
 307
 308 void
 309 write_return_value (struct type *type, char *valbuf)
 310 {
 311   int reg;
 312   int len;
 313
 314   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 315     write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
 316 }
 317
 318 void
 319 store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
 320 {
 321   write_register (2, addr);
 322 }
 323
 324
 325 void
 326 z8k_print_register_hook (int regno)
 327 {
 328   if ((regno & 1) == 0 && regno < 16)
 329     {
 330       unsigned short l[2];
 331
 332       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 333       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 334       printf_unfiltered ("\t");
 335       printf_unfiltered ("%04x%04x", l[0], l[1]);
 336     }
 337
 338   if ((regno & 3) == 0 && regno < 16)
 339     {
 340       unsigned short l[4];
 341
 342       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 343       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 344       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 345       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 346
 347       printf_unfiltered ("\t");
 348       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 349     }
 350   if (regno == 15)
 351     {
 352       unsigned short rval;
 353       int i;
 354
 355       read_relative_register_raw_bytes (regno, (char *) (&rval));
 356
 357       printf_unfiltered ("\n");
 358       for (i = 0; i < 10; i += 2)
 359         {
 360           printf_unfiltered ("(sp+%d=%04x)", i,
 361                              (unsigned int)read_memory_short (rval + i));
 362         }
 363     }
 364
 365 }
 366
 367 void
 368 z8k_pop_frame (void)
 369 {
 370 }
 371
 372 struct cmd_list_element *setmemorylist;
 373
 374 void
 375 z8k_set_pointer_size (int newsize)
 376 {
 377   static int oldsize = 0;
 378
 379   if (oldsize != newsize)
 380     {
 381       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 382       oldsize = newsize;
 383       if (newsize == 32)
 384         {
 385           BIG = 1;
 386         }
 387       else
 388         {
 389           BIG = 0;
 390         }
 391       /* FIXME: This code should be using the GDBARCH framework to
 392          handle changed type sizes.  If this problem is ever fixed
 393          (the direct reference to _initialize_gdbtypes() below
 394          eliminated) then Makefile.in should be updated so that
 395          z8k-tdep.c is again compiled with -Werror. */
 396       _initialize_gdbtypes ();
 397     }
 398 }
 399
 400 static void
 401 segmented_command (char *args, int from_tty)
 402 {
 403   z8k_set_pointer_size (32);
 404 }
 405
 406 static void
 407 unsegmented_command (char *args, int from_tty)
 408 {
 409   z8k_set_pointer_size (16);
 410 }
 411
 412 static void
 413 set_memory (char *args, int from_tty)
 414 {
 415   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 416   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 417 }
 418
 419 void
 420 _initialize_z8ktdep (void)
 421 {
 422   tm_print_insn = gdb_print_insn_z8k;
 423
 424   add_prefix_cmd ("memory", no_class, set_memory,
 425                   "set the memory model", &setmemorylist, "set memory ", 0,
 426                   &setlist);
 427   add_cmd ("segmented", class_support, segmented_command,
 428            "Set segmented memory model.", &setmemorylist);
 429   add_cmd ("unsegmented", class_support, unsegmented_command,
 430            "Set unsegmented memory model.", &setmemorylist);
 431
 432 }