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 "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 (!inside_entry_file (thisframe->pc))
 163     {
 164       return read_memory_pointer (thisframe->frame);
 165     }
 166   return 0;
 167 }
 168
 169 void
 170 init_frame_pc (void)
 171 {
 172   internal_error (__FILE__, __LINE__, "failed internal consistency check");
 173 }
 174
 175 /* Put here the code to store, into a struct frame_saved_regs,
 176    the addresses of the saved registers of frame described by FRAME_INFO.
 177    This includes special registers such as pc and fp saved in special
 178    ways in the stack frame.  sp is even more special:
 179    the address we return for it IS the sp for the next frame.  */
 180
 181 void
 182 z8k_frame_init_saved_regs (struct frame_info *frame_info)
 183 {
 184   CORE_ADDR pc;
 185   int w;
 186
 187   frame_saved_regs_zalloc (frame_info);
 188   pc = get_pc_function_start (frame_info->pc);
 189
 190   /* wander down the instruction stream */
 191   examine_frame (pc, frame_info->saved_regs, frame_info->frame);
 192
 193 }
 194
 195 void
 196 z8k_push_dummy_frame (void)
 197 {
 198   internal_error (__FILE__, __LINE__, "failed internal consistency check");
 199 }
 200
 201 int
 202 gdb_print_insn_z8k (bfd_vma memaddr, disassemble_info *info)
 203 {
 204   if (BIG)
 205     return print_insn_z8001 (memaddr, info);
 206   else
 207     return print_insn_z8002 (memaddr, info);
 208 }
 209
 210 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 211    is not the address of a valid instruction, the address of the next
 212    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 213    of the instruction. */
 214
 215 CORE_ADDR
 216 NEXT_PROLOGUE_INSN (CORE_ADDR addr, CORE_ADDR lim, short *pword1)
 217 {
 218   char buf[2];
 219   if (addr < lim + 8)
 220     {
 221       read_memory (addr, buf, 2);
 222       *pword1 = extract_signed_integer (buf, 2);
 223
 224       return addr + 2;
 225     }
 226   return 0;
 227 }
 228
 229 #if 0
 230 /* Put here the code to store, into a struct frame_saved_regs,
 231    the addresses of the saved registers of frame described by FRAME_INFO.
 232    This includes special registers such as pc and fp saved in special
 233    ways in the stack frame.  sp is even more special:
 234    the address we return for it IS the sp for the next frame.
 235
 236    We cache the result of doing this in the frame_cache_obstack, since
 237    it is fairly expensive.  */
 238
 239 void
 240 frame_find_saved_regs (struct frame_info *fip, struct frame_saved_regs *fsrp)
 241 {
 242   int locals;
 243   CORE_ADDR pc;
 244   CORE_ADDR adr;
 245   int i;
 246
 247   memset (fsrp, 0, sizeof *fsrp);
 248
 249   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 250
 251   {
 252     adr = FRAME_FP (fip) - locals;
 253     for (i = 0; i < 8; i++)
 254       {
 255         int word = read_memory_short (pc);
 256
 257         pc += 2;
 258         if (IS_PUSHL (word))
 259           {
 260             fsrp->regs[word & 0xf] = adr;
 261             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 262             adr -= 4;
 263           }
 264         else if (IS_PUSHW (word))
 265           {
 266             fsrp->regs[word & 0xf] = adr;
 267             adr -= 2;
 268           }
 269         else
 270           break;
 271       }
 272
 273   }
 274
 275   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 276   fsrp->regs[FP_REGNUM] = fip->frame;
 277
 278 }
 279 #endif
 280
 281 int
 282 z8k_saved_pc_after_call (struct frame_info *frame)
 283 {
 284   return ADDR_BITS_REMOVE
 285     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 286 }
 287
 288
 289 void
 290 extract_return_value (struct type *type, char *regbuf, char *valbuf)
 291 {
 292   int b;
 293   int len = TYPE_LENGTH (type);
 294
 295   for (b = 0; b < len; b += 2)
 296     {
 297       int todo = len - b;
 298
 299       if (todo > 2)
 300         todo = 2;
 301       memcpy (valbuf + b, regbuf + b, todo);
 302     }
 303 }
 304
 305 void
 306 write_return_value (struct type *type, char *valbuf)
 307 {
 308   int reg;
 309   int len;
 310
 311   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 312     write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
 313 }
 314
 315 void
 316 store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
 317 {
 318   write_register (2, addr);
 319 }
 320
 321
 322 void
 323 z8k_print_register_hook (int regno)
 324 {
 325   if ((regno & 1) == 0 && regno < 16)
 326     {
 327       unsigned char l[4];
 328
 329       frame_register_read (selected_frame, regno, l + 0);
 330       frame_register_read (selected_frame, regno + 1, l + 2);
 331       printf_unfiltered ("\t");
 332       printf_unfiltered ("0x%02x%02x%02x%02x", l[0], l[1], l[2], l[3]);
 333     }
 334
 335   if ((regno & 3) == 0 && regno < 16)
 336     {
 337       unsigned char l[8];
 338
 339       frame_register_read (selected_frame, regno, l + 0);
 340       frame_register_read (selected_frame, regno + 1, l + 2);
 341       frame_register_read (selected_frame, regno + 2, l + 4);
 342       frame_register_read (selected_frame, regno + 3, l + 6);
 343
 344       printf_unfiltered ("\t");
 345       printf_unfiltered ("0x%02x%02x%02x%02x%02x%02x%02x%02x",
 346                          l[0], l[1], l[2], l[3], l[4], l[5], l[6], l[7]);
 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 }