gdb/z8k-tdep.c

   1 /* Target-machine dependent code for Zilog Z8000, for GDB.
   2    Copyright 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 /*
  23    Contributed by Steve Chamberlain
  24    sac@cygnus.com
  25  */
  26
  27 #include "defs.h"
  28 #include "frame.h"
  29 #include "obstack.h"
  30 #include "symtab.h"
  31 #include "gdbcmd.h"
  32 #include "gdbtypes.h"
  33 #include "dis-asm.h"
  34 #include "gdbcore.h"
  35 #include "regcache.h"
  36
  37 #include "value.h" /* For read_register() */
  38
  39
  40 static int read_memory_pointer (CORE_ADDR x);
  41
  42 /* Return the saved PC from this frame.
  43
  44    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  45    just use the register SRP_REGNUM itself.  */
  46
  47 CORE_ADDR
  48 z8k_frame_saved_pc (struct frame_info *frame)
  49 {
  50   return read_memory_pointer (frame->frame + (BIG ? 4 : 2));
  51 }
  52
  53 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  54 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  55 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  56 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  57 #define IS_SUB2_SP(x) (x==0x1b87)
  58 #define IS_MOVK_R5(x) (x==0x7905)
  59 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  60 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  61
  62 /* work out how much local space is on the stack and
  63    return the pc pointing to the first push */
  64
  65 static CORE_ADDR
  66 skip_adjust (CORE_ADDR pc, int *size)
  67 {
  68   *size = 0;
  69
  70   if (IS_PUSH_FP (read_memory_short (pc))
  71       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  72     {
  73       /* This is a function with an explict frame pointer */
  74       pc += 4;
  75       *size += 2;               /* remember the frame pointer */
  76     }
  77
  78   /* remember any stack adjustment */
  79   if (IS_SUB_SP (read_memory_short (pc)))
  80     {
  81       *size += read_memory_short (pc + 2);
  82       pc += 4;
  83     }
  84   return pc;
  85 }
  86
  87 static CORE_ADDR examine_frame (CORE_ADDR, CORE_ADDR * regs, CORE_ADDR);
  88 static CORE_ADDR
  89 examine_frame (CORE_ADDR pc, CORE_ADDR *regs, CORE_ADDR sp)
  90 {
  91   int w = read_memory_short (pc);
  92   int offset = 0;
  93   int regno;
  94
  95   for (regno = 0; regno < NUM_REGS; regno++)
  96     regs[regno] = 0;
  97
  98   while (IS_PUSHW (w) || IS_PUSHL (w))
  99     {
 100       /* work out which register is being pushed to where */
 101       if (IS_PUSHL (w))
 102         {
 103           regs[w & 0xf] = offset;
 104           regs[(w & 0xf) + 1] = offset + 2;
 105           offset += 4;
 106         }
 107       else
 108         {
 109           regs[w & 0xf] = offset;
 110           offset += 2;
 111         }
 112       pc += 2;
 113       w = read_memory_short (pc);
 114     }
 115
 116   if (IS_MOVE_FP (w))
 117     {
 118       /* We know the fp */
 119
 120     }
 121   else if (IS_SUB_SP (w))
 122     {
 123       /* Subtracting a value from the sp, so were in a function
 124          which needs stack space for locals, but has no fp.  We fake up
 125          the values as if we had an fp */
 126       regs[FP_REGNUM] = sp;
 127     }
 128   else
 129     {
 130       /* This one didn't have an fp, we'll fake it up */
 131       regs[SP_REGNUM] = sp;
 132     }
 133   /* stack pointer contains address of next frame */
 134   /*  regs[fp_regnum()] = fp; */
 135   regs[SP_REGNUM] = sp;
 136   return pc;
 137 }
 138
 139 CORE_ADDR
 140 z8k_skip_prologue (CORE_ADDR start_pc)
 141 {
 142   CORE_ADDR dummy[NUM_REGS];
 143
 144   return examine_frame (start_pc, dummy, 0);
 145 }
 146
 147 CORE_ADDR
 148 z8k_addr_bits_remove (CORE_ADDR addr)
 149 {
 150   return (addr & PTR_MASK);
 151 }
 152
 153 static int
 154 read_memory_pointer (CORE_ADDR x)
 155 {
 156   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 157 }
 158
 159 CORE_ADDR
 160 z8k_frame_chain (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 void
 174 init_frame_pc (void)
 175 {
 176   internal_error (__FILE__, __LINE__, "failed internal consistency check");
 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 z8k_frame_init_saved_regs (struct frame_info *frame_info)
 187 {
 188   CORE_ADDR pc;
 189   int w;
 190
 191   frame_saved_regs_zalloc (frame_info);
 192   pc = get_pc_function_start (frame_info->pc);
 193
 194   /* wander down the instruction stream */
 195   examine_frame (pc, frame_info->saved_regs, frame_info->frame);
 196
 197 }
 198
 199 void
 200 z8k_push_dummy_frame (void)
 201 {
 202   internal_error (__FILE__, __LINE__, "failed internal consistency check");
 203 }
 204
 205 int
 206 gdb_print_insn_z8k (bfd_vma memaddr, disassemble_info *info)
 207 {
 208   if (BIG)
 209     return print_insn_z8001 (memaddr, info);
 210   else
 211     return print_insn_z8002 (memaddr, info);
 212 }
 213
 214 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 215    is not the address of a valid instruction, the address of the next
 216    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 217    of the instruction. */
 218
 219 CORE_ADDR
 220 NEXT_PROLOGUE_INSN (CORE_ADDR addr, CORE_ADDR lim, short *pword1)
 221 {
 222   char buf[2];
 223   if (addr < lim + 8)
 224     {
 225       read_memory (addr, buf, 2);
 226       *pword1 = extract_signed_integer (buf, 2);
 227
 228       return addr + 2;
 229     }
 230   return 0;
 231 }
 232
 233 #if 0
 234 /* Put here the code to store, into a struct frame_saved_regs,
 235    the addresses of the saved registers of frame described by FRAME_INFO.
 236    This includes special registers such as pc and fp saved in special
 237    ways in the stack frame.  sp is even more special:
 238    the address we return for it IS the sp for the next frame.
 239
 240    We cache the result of doing this in the frame_cache_obstack, since
 241    it is fairly expensive.  */
 242
 243 void
 244 frame_find_saved_regs (struct frame_info *fip, struct frame_saved_regs *fsrp)
 245 {
 246   int locals;
 247   CORE_ADDR pc;
 248   CORE_ADDR adr;
 249   int i;
 250
 251   memset (fsrp, 0, sizeof *fsrp);
 252
 253   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 254
 255   {
 256     adr = FRAME_FP (fip) - locals;
 257     for (i = 0; i < 8; i++)
 258       {
 259         int word = read_memory_short (pc);
 260
 261         pc += 2;
 262         if (IS_PUSHL (word))
 263           {
 264             fsrp->regs[word & 0xf] = adr;
 265             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 266             adr -= 4;
 267           }
 268         else if (IS_PUSHW (word))
 269           {
 270             fsrp->regs[word & 0xf] = adr;
 271             adr -= 2;
 272           }
 273         else
 274           break;
 275       }
 276
 277   }
 278
 279   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 280   fsrp->regs[FP_REGNUM] = fip->frame;
 281
 282 }
 283 #endif
 284
 285 int
 286 z8k_saved_pc_after_call (struct frame_info *frame)
 287 {
 288   return ADDR_BITS_REMOVE
 289     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 290 }
 291
 292
 293 void
 294 extract_return_value (struct type *type, char *regbuf, char *valbuf)
 295 {
 296   int b;
 297   int len = TYPE_LENGTH (type);
 298
 299   for (b = 0; b < len; b += 2)
 300     {
 301       int todo = len - b;
 302
 303       if (todo > 2)
 304         todo = 2;
 305       memcpy (valbuf + b, regbuf + b, todo);
 306     }
 307 }
 308
 309 void
 310 write_return_value (struct type *type, char *valbuf)
 311 {
 312   int reg;
 313   int len;
 314
 315   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 316     write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
 317 }
 318
 319 void
 320 store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
 321 {
 322   write_register (2, addr);
 323 }
 324
 325
 326 void
 327 z8k_print_register_hook (int regno)
 328 {
 329   if ((regno & 1) == 0 && regno < 16)
 330     {
 331       unsigned short l[2];
 332
 333       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 334       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 335       printf_unfiltered ("\t");
 336       printf_unfiltered ("%04x%04x", l[0], l[1]);
 337     }
 338
 339   if ((regno & 3) == 0 && regno < 16)
 340     {
 341       unsigned short l[4];
 342
 343       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 344       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 345       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 346       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 347
 348       printf_unfiltered ("\t");
 349       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 350     }
 351   if (regno == 15)
 352     {
 353       unsigned short rval;
 354       int i;
 355
 356       read_relative_register_raw_bytes (regno, (char *) (&rval));
 357
 358       printf_unfiltered ("\n");
 359       for (i = 0; i < 10; i += 2)
 360         {
 361           printf_unfiltered ("(sp+%d=%04x)", i,
 362                              (unsigned int)read_memory_short (rval + i));
 363         }
 364     }
 365
 366 }
 367
 368 void
 369 z8k_pop_frame (void)
 370 {
 371 }
 372
 373 struct cmd_list_element *setmemorylist;
 374
 375 void
 376 z8k_set_pointer_size (int newsize)
 377 {
 378   static int oldsize = 0;
 379
 380   if (oldsize != newsize)
 381     {
 382       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 383       oldsize = newsize;
 384       if (newsize == 32)
 385         {
 386           BIG = 1;
 387         }
 388       else
 389         {
 390           BIG = 0;
 391         }
 392       /* FIXME: This code should be using the GDBARCH framework to
 393          handle changed type sizes.  If this problem is ever fixed
 394          (the direct reference to _initialize_gdbtypes() below
 395          eliminated) then Makefile.in should be updated so that
 396          z8k-tdep.c is again compiled with -Werror. */
 397       _initialize_gdbtypes ();
 398     }
 399 }
 400
 401 static void
 402 segmented_command (char *args, int from_tty)
 403 {
 404   z8k_set_pointer_size (32);
 405 }
 406
 407 static void
 408 unsegmented_command (char *args, int from_tty)
 409 {
 410   z8k_set_pointer_size (16);
 411 }
 412
 413 static void
 414 set_memory (char *args, int from_tty)
 415 {
 416   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 417   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 418 }
 419
 420 void
 421 _initialize_z8ktdep (void)
 422 {
 423   tm_print_insn = gdb_print_insn_z8k;
 424
 425   add_prefix_cmd ("memory", no_class, set_memory,
 426                   "set the memory model", &setmemorylist, "set memory ", 0,
 427                   &setlist);
 428   add_cmd ("segmented", class_support, segmented_command,
 429            "Set segmented memory model.", &setmemorylist);
 430   add_cmd ("unsegmented", class_support, unsegmented_command,
 431            "Set unsegmented memory model.", &setmemorylist);
 432
 433 }