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, Boston, MA 02111-1307, USA.  */
  19
  20 /*
  21  Contributed by Steve Chamberlain
  22                 sac@cygnus.com
  23  */
  24
  25 #include "defs.h"
  26 #include "frame.h"
  27 #include "obstack.h"
  28 #include "symtab.h"
  29 #include "gdbcmd.h"
  30 #include "gdbtypes.h"
  31 #include "dis-asm.h"
  32 #include "gdbcore.h"
  33
  34
  35 /* Return the saved PC from this frame.
  36
  37    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  38    just use the register SRP_REGNUM itself.  */
  39
  40 CORE_ADDR
  41 frame_saved_pc (frame)
  42      struct frame_info *frame;
  43 {
  44   return read_memory_pointer (frame->frame + (BIG ? 4 : 2));
  45 }
  46
  47 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  48 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  49 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  50 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  51 #define IS_SUB2_SP(x) (x==0x1b87)
  52 #define IS_MOVK_R5(x) (x==0x7905)
  53 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  54 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  55
  56 /* work out how much local space is on the stack and
  57    return the pc pointing to the first push */
  58
  59 static CORE_ADDR
  60 skip_adjust (pc, size)
  61      CORE_ADDR pc;
  62      int *size;
  63 {
  64   *size = 0;
  65
  66   if (IS_PUSH_FP (read_memory_short (pc))
  67       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  68     {
  69       /* This is a function with an explict frame pointer */
  70       pc += 4;
  71       *size += 2;               /* remember the frame pointer */
  72     }
  73
  74   /* remember any stack adjustment */
  75   if (IS_SUB_SP (read_memory_short (pc)))
  76     {
  77       *size += read_memory_short (pc + 2);
  78       pc += 4;
  79     }
  80   return pc;
  81 }
  82
  83 int
  84 examine_frame (pc, regs, sp)
  85      CORE_ADDR pc;
  86      struct frame_saved_regs *regs;
  87      CORE_ADDR sp;
  88 {
  89   int w = read_memory_short (pc);
  90   int offset = 0;
  91   int regno;
  92
  93   for (regno = 0; regno < NUM_REGS; regno++)
  94     regs->regs[regno] = 0;
  95
  96   while (IS_PUSHW (w) || IS_PUSHL (w))
  97     {
  98       /* work out which register is being pushed to where */
  99       if (IS_PUSHL (w))
 100         {
 101           regs->regs[w & 0xf] = offset;
 102           regs->regs[(w & 0xf) + 1] = offset + 2;
 103           offset += 4;
 104         }
 105       else
 106         {
 107           regs->regs[w & 0xf] = offset;
 108           offset += 2;
 109         }
 110       pc += 2;
 111       w = read_memory_short (pc);
 112     }
 113
 114   if (IS_MOVE_FP (w))
 115     {
 116       /* We know the fp */
 117
 118     }
 119   else if (IS_SUB_SP (w))
 120     {
 121       /* Subtracting a value from the sp, so were in a function
 122        which needs stack space for locals, but has no fp.  We fake up
 123        the values as if we had an fp */
 124       regs->regs[FP_REGNUM] = sp;
 125     }
 126   else
 127     {
 128       /* This one didn't have an fp, we'll fake it up */
 129       regs->regs[SP_REGNUM] = sp;
 130     }
 131   /* stack pointer contains address of next frame */
 132   /*  regs->regs[fp_regnum()] = fp;*/
 133   regs->regs[SP_REGNUM] = sp;
 134   return pc;
 135 }
 136
 137 CORE_ADDR
 138 z8k_skip_prologue (start_pc)
 139      CORE_ADDR start_pc;
 140 {
 141   struct frame_saved_regs dummy;
 142
 143   return examine_frame (start_pc, &dummy, 0);
 144 }
 145
 146 CORE_ADDR
 147 z8k_addr_bits_remove (addr)
 148      CORE_ADDR addr;
 149 {
 150   return (addr & PTR_MASK);
 151 }
 152
 153 int
 154 read_memory_pointer (x)
 155      CORE_ADDR x;
 156 {
 157   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 158 }
 159
 160 CORE_ADDR
 161 frame_chain (thisframe)
 162      struct frame_info *thisframe;
 163 {
 164   if (thisframe->prev == 0)
 165     {
 166       /* This is the top of the stack, let's get the sp for real */
 167     }
 168   if (!inside_entry_file (thisframe->pc))
 169     {
 170       return read_memory_pointer (thisframe->frame);
 171     }
 172   return 0;
 173 }
 174
 175 init_frame_pc ()
 176 {
 177   abort ();
 178 }
 179
 180 /* Put here the code to store, into a struct frame_saved_regs,
 181    the addresses of the saved registers of frame described by FRAME_INFO.
 182    This includes special registers such as pc and fp saved in special
 183    ways in the stack frame.  sp is even more special:
 184    the address we return for it IS the sp for the next frame.  */
 185
 186 void
 187 get_frame_saved_regs (frame_info, frame_saved_regs)
 188      struct frame_info *frame_info;
 189      struct frame_saved_regs *frame_saved_regs;
 190
 191 {
 192   CORE_ADDR pc;
 193   int w;
 194
 195   memset (frame_saved_regs, '\0', sizeof (*frame_saved_regs));
 196   pc = get_pc_function_start (frame_info->pc);
 197
 198 /* wander down the instruction stream */
 199   examine_frame (pc, frame_saved_regs, frame_info->frame);
 200
 201 }
 202
 203 void
 204 z8k_push_dummy_frame ()
 205 {
 206   abort ();
 207 }
 208
 209 int
 210 gdb_print_insn_z8k (memaddr, info)
 211      bfd_vma memaddr;
 212      disassemble_info *info;
 213 {
 214   if (BIG)
 215     return print_insn_z8001 (memaddr, info);
 216   else
 217     return print_insn_z8002 (memaddr, info);
 218 }
 219
 220 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 221    is not the address of a valid instruction, the address of the next
 222    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 223    of the instruction.*/
 224
 225 CORE_ADDR
 226 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 227      CORE_ADDR addr;
 228      CORE_ADDR lim;
 229      short *pword1;
 230 {
 231   char buf[2];
 232   if (addr < lim + 8)
 233     {
 234       read_memory (addr, buf, 2);
 235       *pword1 = extract_signed_integer (buf, 2);
 236
 237       return addr + 2;
 238     }
 239   return 0;
 240 }
 241
 242 /* Put here the code to store, into a struct frame_saved_regs,
 243    the addresses of the saved registers of frame described by FRAME_INFO.
 244    This includes special registers such as pc and fp saved in special
 245    ways in the stack frame.  sp is even more special:
 246    the address we return for it IS the sp for the next frame.
 247
 248    We cache the result of doing this in the frame_cache_obstack, since
 249    it is fairly expensive.  */
 250
 251 void
 252 frame_find_saved_regs (fip, fsrp)
 253      struct frame_info *fip;
 254      struct frame_saved_regs *fsrp;
 255 {
 256   int locals;
 257   CORE_ADDR pc;
 258   CORE_ADDR adr;
 259   int i;
 260
 261   memset (fsrp, 0, sizeof *fsrp);
 262
 263   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 264
 265   {
 266     adr = FRAME_FP (fip) - locals;
 267     for (i = 0; i < 8; i++)
 268       {
 269         int word = read_memory_short (pc);
 270
 271         pc += 2;
 272         if (IS_PUSHL (word))
 273           {
 274             fsrp->regs[word & 0xf] = adr;
 275             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 276             adr -= 4;
 277           }
 278         else if (IS_PUSHW (word))
 279           {
 280             fsrp->regs[word & 0xf] = adr;
 281             adr -= 2;
 282           }
 283         else
 284           break;
 285       }
 286
 287   }
 288
 289   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 290   fsrp->regs[FP_REGNUM] = fip->frame;
 291
 292 }
 293
 294 int
 295 saved_pc_after_call ()
 296 {
 297   return ADDR_BITS_REMOVE
 298     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 299 }
 300
 301
 302 extract_return_value (type, regbuf, valbuf)
 303      struct type *type;
 304      char *regbuf;
 305      char *valbuf;
 306 {
 307   int b;
 308   int len = TYPE_LENGTH (type);
 309
 310   for (b = 0; b < len; b += 2)
 311     {
 312       int todo = len - b;
 313
 314       if (todo > 2)
 315         todo = 2;
 316       memcpy (valbuf + b, regbuf + b, todo);
 317     }
 318 }
 319
 320 void
 321 write_return_value (type, valbuf)
 322      struct type *type;
 323      char *valbuf;
 324 {
 325   int reg;
 326   int len;
 327
 328   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 329     write_register_bytes (REGISTER_BYTE (len / 2  + 2), valbuf + len, 2);
 330 }
 331
 332 void
 333 store_struct_return (addr, sp)
 334      CORE_ADDR addr;
 335      CORE_ADDR sp;
 336 {
 337   write_register (2, addr);
 338 }
 339
 340
 341 void
 342 print_register_hook (regno)
 343      int regno;
 344 {
 345   if ((regno & 1) == 0 && regno < 16)
 346     {
 347       unsigned short l[2];
 348
 349       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 350       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 351       printf_unfiltered ("\t");
 352       printf_unfiltered ("%04x%04x", l[0], l[1]);
 353     }
 354
 355   if ((regno & 3) == 0 && regno < 16)
 356     {
 357       unsigned short l[4];
 358
 359       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 360       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 361       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 362       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 363
 364       printf_unfiltered ("\t");
 365       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 366     }
 367   if (regno == 15)
 368     {
 369       unsigned short rval;
 370       int i;
 371
 372       read_relative_register_raw_bytes (regno, (char *) (&rval));
 373
 374       printf_unfiltered ("\n");
 375       for (i = 0; i < 10; i += 2)
 376         {
 377           printf_unfiltered ("(sp+%d=%04x)", i, read_memory_short (rval + i));
 378         }
 379     }
 380
 381 }
 382
 383 void
 384 z8k_pop_frame ()
 385 {
 386 }
 387
 388 struct cmd_list_element *setmemorylist;
 389
 390 void
 391 z8k_set_pointer_size (newsize)
 392      int newsize;
 393 {
 394   static int oldsize = 0;
 395
 396   if (oldsize != newsize)
 397     {
 398       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 399       oldsize = newsize;
 400       if (newsize == 32)
 401         {
 402           BIG = 1;
 403         }
 404       else
 405         {
 406           BIG = 0;
 407         }
 408       _initialize_gdbtypes ();
 409     }
 410 }
 411
 412 static void
 413 segmented_command (args, from_tty)
 414      char *args;
 415      int from_tty;
 416 {
 417   z8k_set_pointer_size (32);
 418 }
 419
 420 static void
 421 unsegmented_command (args, from_tty)
 422      char *args;
 423      int from_tty;
 424 {
 425   z8k_set_pointer_size (16);
 426 }
 427
 428 static void
 429 set_memory (args, from_tty)
 430      char *args;
 431      int from_tty;
 432 {
 433   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 434   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 435 }
 436
 437 void
 438 _initialize_z8ktdep ()
 439 {
 440   tm_print_insn = gdb_print_insn_z8k;
 441
 442   add_prefix_cmd ("memory", no_class, set_memory,
 443                   "set the memory model", &setmemorylist, "set memory ", 0,
 444                   &setlist);
 445   add_cmd ("segmented", class_support, segmented_command,
 446            "Set segmented memory model.", &setmemorylist);
 447   add_cmd ("unsegmented", class_support, unsegmented_command,
 448            "Set unsegmented memory model.", &setmemorylist);
 449
 450 }