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
  36 /* Return the saved PC from this frame.
  37
  38    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  39    just use the register SRP_REGNUM itself.  */
  40
  41 CORE_ADDR
  42 frame_saved_pc (frame)
  43      struct frame_info *frame;
  44 {
  45   return read_memory_pointer (frame->frame + (BIG ? 4 : 2));
  46 }
  47
  48 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  49 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  50 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  51 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  52 #define IS_SUB2_SP(x) (x==0x1b87)
  53 #define IS_MOVK_R5(x) (x==0x7905)
  54 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  55 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  56
  57 /* work out how much local space is on the stack and
  58    return the pc pointing to the first push */
  59
  60 static CORE_ADDR
  61 skip_adjust (pc, size)
  62      CORE_ADDR pc;
  63      int *size;
  64 {
  65   *size = 0;
  66
  67   if (IS_PUSH_FP (read_memory_short (pc))
  68       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  69     {
  70       /* This is a function with an explict frame pointer */
  71       pc += 4;
  72       *size += 2;               /* remember the frame pointer */
  73     }
  74
  75   /* remember any stack adjustment */
  76   if (IS_SUB_SP (read_memory_short (pc)))
  77     {
  78       *size += read_memory_short (pc + 2);
  79       pc += 4;
  80     }
  81   return pc;
  82 }
  83
  84 static CORE_ADDR examine_frame PARAMS ((CORE_ADDR, CORE_ADDR * regs, CORE_ADDR));
  85 static CORE_ADDR
  86 examine_frame (pc, regs, sp)
  87      CORE_ADDR pc;
  88      CORE_ADDR *regs;
  89      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 (start_pc)
 141      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 (addr)
 150      CORE_ADDR addr;
 151 {
 152   return (addr & PTR_MASK);
 153 }
 154
 155 int
 156 read_memory_pointer (x)
 157      CORE_ADDR x;
 158 {
 159   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 160 }
 161
 162 CORE_ADDR
 163 frame_chain (thisframe)
 164      struct frame_info *thisframe;
 165 {
 166   if (thisframe->prev == 0)
 167     {
 168       /* This is the top of the stack, let's get the sp for real */
 169     }
 170   if (!inside_entry_file (thisframe->pc))
 171     {
 172       return read_memory_pointer (thisframe->frame);
 173     }
 174   return 0;
 175 }
 176
 177 void
 178 init_frame_pc ()
 179 {
 180   abort ();
 181 }
 182
 183 /* Put here the code to store, into a struct frame_saved_regs,
 184    the addresses of the saved registers of frame described by FRAME_INFO.
 185    This includes special registers such as pc and fp saved in special
 186    ways in the stack frame.  sp is even more special:
 187    the address we return for it IS the sp for the next frame.  */
 188
 189 void
 190 z8k_frame_init_saved_regs (frame_info)
 191      struct frame_info *frame_info;
 192 {
 193   CORE_ADDR pc;
 194   int w;
 195
 196   frame_saved_regs_zalloc (frame_info);
 197   pc = get_pc_function_start (frame_info->pc);
 198
 199   /* wander down the instruction stream */
 200   examine_frame (pc, frame_info->saved_regs, frame_info->frame);
 201
 202 }
 203
 204 void
 205 z8k_push_dummy_frame ()
 206 {
 207   abort ();
 208 }
 209
 210 int
 211 gdb_print_insn_z8k (memaddr, info)
 212      bfd_vma memaddr;
 213      disassemble_info *info;
 214 {
 215   if (BIG)
 216     return print_insn_z8001 (memaddr, info);
 217   else
 218     return print_insn_z8002 (memaddr, info);
 219 }
 220
 221 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 222    is not the address of a valid instruction, the address of the next
 223    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 224    of the instruction. */
 225
 226 CORE_ADDR
 227 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 228      CORE_ADDR addr;
 229      CORE_ADDR lim;
 230      short *pword1;
 231 {
 232   char buf[2];
 233   if (addr < lim + 8)
 234     {
 235       read_memory (addr, buf, 2);
 236       *pword1 = extract_signed_integer (buf, 2);
 237
 238       return addr + 2;
 239     }
 240   return 0;
 241 }
 242
 243 #if 0
 244 /* Put here the code to store, into a struct frame_saved_regs,
 245    the addresses of the saved registers of frame described by FRAME_INFO.
 246    This includes special registers such as pc and fp saved in special
 247    ways in the stack frame.  sp is even more special:
 248    the address we return for it IS the sp for the next frame.
 249
 250    We cache the result of doing this in the frame_cache_obstack, since
 251    it is fairly expensive.  */
 252
 253 void
 254 frame_find_saved_regs (fip, fsrp)
 255      struct frame_info *fip;
 256      struct frame_saved_regs *fsrp;
 257 {
 258   int locals;
 259   CORE_ADDR pc;
 260   CORE_ADDR adr;
 261   int i;
 262
 263   memset (fsrp, 0, sizeof *fsrp);
 264
 265   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 266
 267   {
 268     adr = FRAME_FP (fip) - locals;
 269     for (i = 0; i < 8; i++)
 270       {
 271         int word = read_memory_short (pc);
 272
 273         pc += 2;
 274         if (IS_PUSHL (word))
 275           {
 276             fsrp->regs[word & 0xf] = adr;
 277             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 278             adr -= 4;
 279           }
 280         else if (IS_PUSHW (word))
 281           {
 282             fsrp->regs[word & 0xf] = adr;
 283             adr -= 2;
 284           }
 285         else
 286           break;
 287       }
 288
 289   }
 290
 291   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 292   fsrp->regs[FP_REGNUM] = fip->frame;
 293
 294 }
 295 #endif
 296
 297 int
 298 saved_pc_after_call ()
 299 {
 300   return ADDR_BITS_REMOVE
 301     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 302 }
 303
 304
 305 void
 306 extract_return_value (type, regbuf, valbuf)
 307      struct type *type;
 308      char *regbuf;
 309      char *valbuf;
 310 {
 311   int b;
 312   int len = TYPE_LENGTH (type);
 313
 314   for (b = 0; b < len; b += 2)
 315     {
 316       int todo = len - b;
 317
 318       if (todo > 2)
 319         todo = 2;
 320       memcpy (valbuf + b, regbuf + b, todo);
 321     }
 322 }
 323
 324 void
 325 write_return_value (type, valbuf)
 326      struct type *type;
 327      char *valbuf;
 328 {
 329   int reg;
 330   int len;
 331
 332   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 333     write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
 334 }
 335
 336 void
 337 store_struct_return (addr, sp)
 338      CORE_ADDR addr;
 339      CORE_ADDR sp;
 340 {
 341   write_register (2, addr);
 342 }
 343
 344
 345 void
 346 print_register_hook (regno)
 347      int regno;
 348 {
 349   if ((regno & 1) == 0 && regno < 16)
 350     {
 351       unsigned short l[2];
 352
 353       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 354       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 355       printf_unfiltered ("\t");
 356       printf_unfiltered ("%04x%04x", l[0], l[1]);
 357     }
 358
 359   if ((regno & 3) == 0 && regno < 16)
 360     {
 361       unsigned short l[4];
 362
 363       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 364       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 365       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 366       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 367
 368       printf_unfiltered ("\t");
 369       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 370     }
 371   if (regno == 15)
 372     {
 373       unsigned short rval;
 374       int i;
 375
 376       read_relative_register_raw_bytes (regno, (char *) (&rval));
 377
 378       printf_unfiltered ("\n");
 379       for (i = 0; i < 10; i += 2)
 380         {
 381           printf_unfiltered ("(sp+%d=%04x)", i, read_memory_short (rval + i));
 382         }
 383     }
 384
 385 }
 386
 387 void
 388 z8k_pop_frame ()
 389 {
 390 }
 391
 392 struct cmd_list_element *setmemorylist;
 393
 394 void
 395 z8k_set_pointer_size (newsize)
 396      int newsize;
 397 {
 398   static int oldsize = 0;
 399
 400   if (oldsize != newsize)
 401     {
 402       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 403       oldsize = newsize;
 404       if (newsize == 32)
 405         {
 406           BIG = 1;
 407         }
 408       else
 409         {
 410           BIG = 0;
 411         }
 412       _initialize_gdbtypes ();
 413     }
 414 }
 415
 416 static void
 417 segmented_command (args, from_tty)
 418      char *args;
 419      int from_tty;
 420 {
 421   z8k_set_pointer_size (32);
 422 }
 423
 424 static void
 425 unsegmented_command (args, from_tty)
 426      char *args;
 427      int from_tty;
 428 {
 429   z8k_set_pointer_size (16);
 430 }
 431
 432 static void
 433 set_memory (args, from_tty)
 434      char *args;
 435      int from_tty;
 436 {
 437   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 438   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 439 }
 440
 441 void
 442 _initialize_z8ktdep ()
 443 {
 444   tm_print_insn = gdb_print_insn_z8k;
 445
 446   add_prefix_cmd ("memory", no_class, set_memory,
 447                   "set the memory model", &setmemorylist, "set memory ", 0,
 448                   &setlist);
 449   add_cmd ("segmented", class_support, segmented_command,
 450            "Set segmented memory model.", &setmemorylist);
 451   add_cmd ("unsegmented", class_support, unsegmented_command,
 452            "Set unsegmented memory model.", &setmemorylist);
 453
 454 }