gdb/z8k-tdep.c

   1 /* Target-machine dependent code for Zilog Z8000, for GDB.
   2
   3    Copyright 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
   4    2002 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 /*
  24    Contributed by Steve Chamberlain
  25    sac@cygnus.com
  26  */
  27
  28 #include "defs.h"
  29 #include "frame.h"
  30 #include "obstack.h"
  31 #include "symtab.h"
  32 #include "gdbcmd.h"
  33 #include "gdbtypes.h"
  34 #include "dis-asm.h"
  35 #include "gdbcore.h"
  36 #include "regcache.h"
  37
  38 #include "value.h" /* For read_register() */
  39
  40
  41 static int read_memory_pointer (CORE_ADDR x);
  42
  43 /* Return the saved PC from this frame.
  44
  45    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  46    just use the register SRP_REGNUM itself.  */
  47
  48 CORE_ADDR
  49 z8k_frame_saved_pc (struct frame_info *frame)
  50 {
  51   return read_memory_pointer (frame->frame + (BIG ? 4 : 2));
  52 }
  53
  54 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  55 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  56 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  57 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  58 #define IS_SUB2_SP(x) (x==0x1b87)
  59 #define IS_MOVK_R5(x) (x==0x7905)
  60 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  61 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  62
  63 /* work out how much local space is on the stack and
  64    return the pc pointing to the first push */
  65
  66 static CORE_ADDR
  67 skip_adjust (CORE_ADDR pc, 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 (CORE_ADDR, CORE_ADDR * regs, CORE_ADDR);
  89 static CORE_ADDR
  90 examine_frame (CORE_ADDR pc, CORE_ADDR *regs, CORE_ADDR sp)
  91 {
  92   int w = read_memory_short (pc);
  93   int offset = 0;
  94   int regno;
  95
  96   for (regno = 0; regno < NUM_REGS; regno++)
  97     regs[regno] = 0;
  98
  99   while (IS_PUSHW (w) || IS_PUSHL (w))
 100     {
 101       /* work out which register is being pushed to where */
 102       if (IS_PUSHL (w))
 103         {
 104           regs[w & 0xf] = offset;
 105           regs[(w & 0xf) + 1] = offset + 2;
 106           offset += 4;
 107         }
 108       else
 109         {
 110           regs[w & 0xf] = offset;
 111           offset += 2;
 112         }
 113       pc += 2;
 114       w = read_memory_short (pc);
 115     }
 116
 117   if (IS_MOVE_FP (w))
 118     {
 119       /* We know the fp */
 120
 121     }
 122   else if (IS_SUB_SP (w))
 123     {
 124       /* Subtracting a value from the sp, so were in a function
 125          which needs stack space for locals, but has no fp.  We fake up
 126          the values as if we had an fp */
 127       regs[FP_REGNUM] = sp;
 128     }
 129   else
 130     {
 131       /* This one didn't have an fp, we'll fake it up */
 132       regs[SP_REGNUM] = sp;
 133     }
 134   /* stack pointer contains address of next frame */
 135   /*  regs[fp_regnum()] = fp; */
 136   regs[SP_REGNUM] = sp;
 137   return pc;
 138 }
 139
 140 CORE_ADDR
 141 z8k_skip_prologue (CORE_ADDR start_pc)
 142 {
 143   CORE_ADDR dummy[NUM_REGS];
 144
 145   return examine_frame (start_pc, dummy, 0);
 146 }
 147
 148 CORE_ADDR
 149 z8k_addr_bits_remove (CORE_ADDR addr)
 150 {
 151   return (addr & PTR_MASK);
 152 }
 153
 154 static int
 155 read_memory_pointer (CORE_ADDR x)
 156 {
 157   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 158 }
 159
 160 CORE_ADDR
 161 z8k_frame_chain (struct frame_info *thisframe)
 162 {
 163   if (!inside_entry_file (thisframe->pc))
 164     {
 165       return read_memory_pointer (thisframe->frame);
 166     }
 167   return 0;
 168 }
 169
 170 void
 171 init_frame_pc (void)
 172 {
 173   internal_error (__FILE__, __LINE__, "failed internal consistency check");
 174 }
 175
 176 /* Put here the code to store, into a struct frame_saved_regs,
 177    the addresses of the saved registers of frame described by FRAME_INFO.
 178    This includes special registers such as pc and fp saved in special
 179    ways in the stack frame.  sp is even more special:
 180    the address we return for it IS the sp for the next frame.  */
 181
 182 void
 183 z8k_frame_init_saved_regs (struct frame_info *frame_info)
 184 {
 185   CORE_ADDR pc;
 186   int w;
 187
 188   frame_saved_regs_zalloc (frame_info);
 189   pc = get_pc_function_start (frame_info->pc);
 190
 191   /* wander down the instruction stream */
 192   examine_frame (pc, frame_info->saved_regs, frame_info->frame);
 193
 194 }
 195
 196 void
 197 z8k_push_dummy_frame (void)
 198 {
 199   internal_error (__FILE__, __LINE__, "failed internal consistency check");
 200 }
 201
 202 int
 203 gdb_print_insn_z8k (bfd_vma memaddr, disassemble_info *info)
 204 {
 205   if (BIG)
 206     return print_insn_z8001 (memaddr, info);
 207   else
 208     return print_insn_z8002 (memaddr, info);
 209 }
 210
 211 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 212    is not the address of a valid instruction, the address of the next
 213    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 214    of the instruction. */
 215
 216 CORE_ADDR
 217 NEXT_PROLOGUE_INSN (CORE_ADDR addr, CORE_ADDR lim, short *pword1)
 218 {
 219   char buf[2];
 220   if (addr < lim + 8)
 221     {
 222       read_memory (addr, buf, 2);
 223       *pword1 = extract_signed_integer (buf, 2);
 224
 225       return addr + 2;
 226     }
 227   return 0;
 228 }
 229
 230 #if 0
 231 /* Put here the code to store, into a struct frame_saved_regs,
 232    the addresses of the saved registers of frame described by FRAME_INFO.
 233    This includes special registers such as pc and fp saved in special
 234    ways in the stack frame.  sp is even more special:
 235    the address we return for it IS the sp for the next frame.
 236
 237    We cache the result of doing this in the frame_cache_obstack, since
 238    it is fairly expensive.  */
 239
 240 void
 241 frame_find_saved_regs (struct frame_info *fip, struct frame_saved_regs *fsrp)
 242 {
 243   int locals;
 244   CORE_ADDR pc;
 245   CORE_ADDR adr;
 246   int i;
 247
 248   memset (fsrp, 0, sizeof *fsrp);
 249
 250   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 251
 252   {
 253     adr = FRAME_FP (fip) - locals;
 254     for (i = 0; i < 8; i++)
 255       {
 256         int word = read_memory_short (pc);
 257
 258         pc += 2;
 259         if (IS_PUSHL (word))
 260           {
 261             fsrp->regs[word & 0xf] = adr;
 262             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 263             adr -= 4;
 264           }
 265         else if (IS_PUSHW (word))
 266           {
 267             fsrp->regs[word & 0xf] = adr;
 268             adr -= 2;
 269           }
 270         else
 271           break;
 272       }
 273
 274   }
 275
 276   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 277   fsrp->regs[FP_REGNUM] = fip->frame;
 278
 279 }
 280 #endif
 281
 282 int
 283 z8k_saved_pc_after_call (struct frame_info *frame)
 284 {
 285   return ADDR_BITS_REMOVE
 286     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 287 }
 288
 289
 290 void
 291 extract_return_value (struct type *type, char *regbuf, char *valbuf)
 292 {
 293   int b;
 294   int len = TYPE_LENGTH (type);
 295
 296   for (b = 0; b < len; b += 2)
 297     {
 298       int todo = len - b;
 299
 300       if (todo > 2)
 301         todo = 2;
 302       memcpy (valbuf + b, regbuf + b, todo);
 303     }
 304 }
 305
 306 void
 307 write_return_value (struct type *type, char *valbuf)
 308 {
 309   int reg;
 310   int len;
 311
 312   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 313     write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
 314 }
 315
 316 void
 317 store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
 318 {
 319   write_register (2, addr);
 320 }
 321
 322
 323 void
 324 z8k_print_register_hook (int regno)
 325 {
 326   if ((regno & 1) == 0 && regno < 16)
 327     {
 328       unsigned short l[2];
 329
 330       frame_register_read (selected_frame, regno, (char *) (l + 0));
 331       frame_register_read (selected_frame, regno + 1, (char *) (l + 1));
 332       printf_unfiltered ("\t");
 333       printf_unfiltered ("%04x%04x", l[0], l[1]);
 334     }
 335
 336   if ((regno & 3) == 0 && regno < 16)
 337     {
 338       unsigned short l[4];
 339
 340       frame_register_read (selected_frame, regno, (char *) (l + 0));
 341       frame_register_read (selected_frame, regno + 1, (char *) (l + 1));
 342       frame_register_read (selected_frame, regno + 2, (char *) (l + 2));
 343       frame_register_read (selected_frame, regno + 3, (char *) (l + 3));
 344
 345       printf_unfiltered ("\t");
 346       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 347     }
 348   if (regno == 15)
 349     {
 350       unsigned short rval;
 351       int i;
 352
 353       frame_register_read (selected_frame, regno, (char *) (&rval));
 354
 355       printf_unfiltered ("\n");
 356       for (i = 0; i < 10; i += 2)
 357         {
 358           printf_unfiltered ("(sp+%d=%04x)", i,
 359                              (unsigned int)read_memory_short (rval + i));
 360         }
 361     }
 362
 363 }
 364
 365 void
 366 z8k_pop_frame (void)
 367 {
 368 }
 369
 370 struct cmd_list_element *setmemorylist;
 371
 372 void
 373 z8k_set_pointer_size (int newsize)
 374 {
 375   static int oldsize = 0;
 376
 377   if (oldsize != newsize)
 378     {
 379       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 380       oldsize = newsize;
 381       if (newsize == 32)
 382         {
 383           BIG = 1;
 384         }
 385       else
 386         {
 387           BIG = 0;
 388         }
 389       /* FIXME: This code should be using the GDBARCH framework to
 390          handle changed type sizes.  If this problem is ever fixed
 391          (the direct reference to _initialize_gdbtypes() below
 392          eliminated) then Makefile.in should be updated so that
 393          z8k-tdep.c is again compiled with -Werror. */
 394       _initialize_gdbtypes ();
 395     }
 396 }
 397
 398 static void
 399 segmented_command (char *args, int from_tty)
 400 {
 401   z8k_set_pointer_size (32);
 402 }
 403
 404 static void
 405 unsegmented_command (char *args, int from_tty)
 406 {
 407   z8k_set_pointer_size (16);
 408 }
 409
 410 static void
 411 set_memory (char *args, int from_tty)
 412 {
 413   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 414   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 415 }
 416
 417 void
 418 _initialize_z8ktdep (void)
 419 {
 420   tm_print_insn = gdb_print_insn_z8k;
 421
 422   add_prefix_cmd ("memory", no_class, set_memory,
 423                   "set the memory model", &setmemorylist, "set memory ", 0,
 424                   &setlist);
 425   add_cmd ("segmented", class_support, segmented_command,
 426            "Set segmented memory model.", &setmemorylist);
 427   add_cmd ("unsegmented", class_support, unsegmented_command,
 428            "Set unsegmented memory model.", &setmemorylist);
 429
 430 }