gdb/z8k-tdep.c

   1 /* Target-machine dependent code for Zilog Z8000, for GDB.
   2    Copyright (C) 1992,1993 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., 675 Mass Ave, Cambridge, MA 02139, 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
  32 /* Return the saved PC from this frame.
  33
  34    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  35    just use the register SRP_REGNUM itself.  */
  36
  37 CORE_ADDR
  38 frame_saved_pc (frame)
  39      FRAME frame;
  40 {
  41   return (read_memory_pointer (frame->frame + (BIG ? 4 : 2)));
  42 }
  43
  44 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  45 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  46 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  47 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  48 #define IS_SUB2_SP(x) (x==0x1b87)
  49 #define IS_MOVK_R5(x) (x==0x7905)
  50 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  51 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  52
  53 /* work out how much local space is on the stack and
  54    return the pc pointing to the first push */
  55
  56 static CORE_ADDR
  57 skip_adjust (pc, size)
  58      CORE_ADDR pc;
  59      int *size;
  60 {
  61   *size = 0;
  62
  63   if (IS_PUSH_FP (read_memory_short (pc))
  64       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  65     {
  66       /* This is a function with an explict frame pointer */
  67       pc += 4;
  68       *size += 2;               /* remember the frame pointer */
  69     }
  70
  71   /* remember any stack adjustment */
  72   if (IS_SUB_SP (read_memory_short (pc)))
  73     {
  74       *size += read_memory_short (pc + 2);
  75       pc += 4;
  76     }
  77   return pc;
  78 }
  79
  80 int
  81 examine_frame (pc, regs, sp)
  82      CORE_ADDR pc;
  83      struct frame_saved_regs *regs;
  84      CORE_ADDR sp;
  85 {
  86   int w = read_memory_short (pc);
  87   int offset = 0;
  88   int regno;
  89
  90   for (regno = 0; regno < NUM_REGS; regno++)
  91     regs->regs[regno] = 0;
  92
  93   while (IS_PUSHW (w) || IS_PUSHL (w))
  94     {
  95       /* work out which register is being pushed to where */
  96       if (IS_PUSHL (w))
  97         {
  98           regs->regs[w & 0xf] = offset;
  99           regs->regs[(w & 0xf) + 1] = offset + 2;
 100           offset += 4;
 101         }
 102       else
 103         {
 104           regs->regs[w & 0xf] = offset;
 105           offset += 2;
 106         }
 107       pc += 2;
 108       w = read_memory_short (pc);
 109     }
 110
 111   if (IS_MOVE_FP (w))
 112     {
 113       /* We know the fp */
 114
 115     }
 116   else if (IS_SUB_SP (w))
 117     {
 118       /* Subtracting a value from the sp, so were in a function
 119        which needs stack space for locals, but has no fp.  We fake up
 120        the values as if we had an fp */
 121       regs->regs[FP_REGNUM] = sp;
 122     }
 123   else
 124     {
 125       /* This one didn't have an fp, we'll fake it up */
 126       regs->regs[SP_REGNUM] = sp;
 127     }
 128   /* stack pointer contains address of next frame */
 129   /*  regs->regs[fp_regnum()] = fp;*/
 130   regs->regs[SP_REGNUM] = sp;
 131   return pc;
 132 }
 133
 134 CORE_ADDR
 135 z8k_skip_prologue (start_pc)
 136      CORE_ADDR start_pc;
 137 {
 138   struct frame_saved_regs dummy;
 139
 140   return examine_frame (start_pc, &dummy, 0);
 141 }
 142
 143 CORE_ADDR
 144 addr_bits_remove (x)
 145      CORE_ADDR x;
 146 {
 147   return x & PTR_MASK;
 148 }
 149
 150 read_memory_pointer (x)
 151      CORE_ADDR x;
 152 {
 153
 154   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 155 }
 156
 157 FRAME_ADDR
 158 frame_chain (thisframe)
 159      FRAME thisframe;
 160 {
 161   if (thisframe->prev == 0)
 162     {
 163       /* This is the top of the stack, let's get the sp for real */
 164     }
 165   if (!inside_entry_file ((thisframe)->pc))
 166     {
 167       return read_memory_pointer ((thisframe)->frame);
 168     }
 169   return 0;
 170 }
 171
 172 init_frame_pc ()
 173 {
 174   abort ();
 175 }
 176
 177 /* Put here the code to store, into a struct frame_saved_regs,
 178    the addresses of the saved registers of frame described by FRAME_INFO.
 179    This includes special registers such as pc and fp saved in special
 180    ways in the stack frame.  sp is even more special:
 181    the address we return for it IS the sp for the next frame.  */
 182
 183 void
 184 get_frame_saved_regs (frame_info, frame_saved_regs)
 185      struct frame_info *frame_info;
 186      struct frame_saved_regs *frame_saved_regs;
 187
 188 {
 189   CORE_ADDR pc;
 190   int w;
 191
 192   bzero (frame_saved_regs, sizeof (*frame_saved_regs));
 193   pc = get_pc_function_start (frame_info->pc);
 194
 195 /* wander down the instruction stream */
 196   examine_frame (pc, frame_saved_regs, frame_info->frame);
 197
 198 }
 199
 200 void
 201 z8k_push_dummy_frame ()
 202 {
 203   abort ();
 204 }
 205
 206 int
 207 print_insn (memaddr, stream)
 208      CORE_ADDR memaddr;
 209      FILE *stream;
 210 {
 211   char temp[20];
 212   disassemble_info info;
 213
 214   GDB_INIT_DISASSEMBLE_INFO(info, stream);
 215
 216   read_memory (memaddr, temp, 20);
 217   if (BIG)
 218     {
 219       return print_insn_z8001 (memaddr, temp, &info);
 220     }
 221   else
 222     {
 223       return print_insn_z8002 (memaddr, temp, &info);
 224     }
 225 }
 226
 227 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 228    is not the address of a valid instruction, the address of the next
 229    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 230    of the instruction.*/
 231
 232 CORE_ADDR
 233 NEXT_PROLOGUE_INSN (addr, lim, pword1)
 234      CORE_ADDR addr;
 235      CORE_ADDR lim;
 236      short *pword1;
 237 {
 238   if (addr < lim + 8)
 239     {
 240       read_memory (addr, pword1, sizeof (*pword1));
 241       SWAP_TARGET_AND_HOST (pword1, sizeof (short));
 242
 243       return addr + 2;
 244     }
 245
 246   return 0;
 247
 248 }
 249
 250 /* Put here the code to store, into a struct frame_saved_regs,
 251    the addresses of the saved registers of frame described by FRAME_INFO.
 252    This includes special registers such as pc and fp saved in special
 253    ways in the stack frame.  sp is even more special:
 254    the address we return for it IS the sp for the next frame.
 255
 256    We cache the result of doing this in the frame_cache_obstack, since
 257    it is fairly expensive.  */
 258
 259 void
 260 frame_find_saved_regs (fip, fsrp)
 261      struct frame_info *fip;
 262      struct frame_saved_regs *fsrp;
 263 {
 264   int locals;
 265   CORE_ADDR pc;
 266   CORE_ADDR adr;
 267   int i;
 268
 269   memset (fsrp, 0, sizeof *fsrp);
 270
 271   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 272
 273   {
 274     adr = fip->frame - locals;
 275     for (i = 0; i < 8; i++)
 276       {
 277         int word = read_memory_short (pc);
 278
 279         pc += 2;
 280         if (IS_PUSHL (word))
 281           {
 282             fsrp->regs[word & 0xf] = adr;
 283             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 284             adr -= 4;
 285           }
 286         else if (IS_PUSHW (word))
 287           {
 288             fsrp->regs[word & 0xf] = adr;
 289             adr -= 2;
 290           }
 291         else
 292           break;
 293       }
 294
 295   }
 296
 297   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 298   fsrp->regs[FP_REGNUM] = fip->frame;
 299
 300 }
 301
 302 void
 303 addr_bits_set ()
 304 {
 305   abort ();
 306 }
 307
 308 int
 309 saved_pc_after_call ()
 310 {
 311   return addr_bits_remove
 312     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 313 }
 314
 315
 316 extract_return_value(type, regbuf, valbuf)
 317 struct type *type;
 318 char *regbuf;
 319 char *valbuf;
 320 {
 321   int b;
 322   int len = TYPE_LENGTH(type);
 323
 324   for (b = 0; b < len; b += 2) {
 325     int todo = len - b;
 326     if (todo > 2)
 327       todo = 2;
 328     memcpy(valbuf + b, regbuf + b, todo);
 329   }
 330 }
 331
 332 void
 333 write_return_value(type, valbuf)
 334 struct type *type;
 335 char *valbuf;
 336 {
 337   int reg;
 338   int len;
 339   for (len = 0; len <  TYPE_LENGTH(type); len += 2)
 340     {
 341       write_register_bytes(REGISTER_BYTE(len /2  + 2), valbuf + len, 2);
 342     }
 343 }
 344
 345 void
 346 store_struct_return(addr, sp)
 347 CORE_ADDR addr;
 348 CORE_ADDR sp;
 349 {
 350   write_register(2, addr);
 351 }
 352
 353
 354 void
 355 print_register_hook (regno)
 356      int regno;
 357 {
 358   if ((regno & 1) == 0 && regno < 16)
 359     {
 360       unsigned short l[2];
 361
 362       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 363       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 364       printf ("\t");
 365       printf ("%04x%04x", l[0], l[1]);
 366     }
 367
 368   if ((regno & 3) == 0 && regno < 16)
 369     {
 370       unsigned short l[4];
 371
 372       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 373       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 374       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 375       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 376
 377       printf ("\t");
 378       printf ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 379     }
 380   if (regno == 15)
 381     {
 382       unsigned short rval;
 383       int i;
 384
 385       read_relative_register_raw_bytes (regno, (char *) (&rval));
 386
 387       printf ("\n");
 388       for (i = 0; i < 10; i += 2)
 389         {
 390           printf ("(sp+%d=%04x)", i, read_memory_short (rval + i));
 391         }
 392     }
 393
 394 }
 395
 396 void
 397 register_convert_to_virtual (regnum, from, to)
 398      unsigned char *from;
 399      unsigned char *to;
 400 {
 401   to[0] = from[0];
 402   to[1] = from[1];
 403   to[2] = from[2];
 404   to[3] = from[3];
 405 }
 406
 407 void
 408 register_convert_to_raw (regnum, to, from)
 409      char *to;
 410      char *from;
 411 {
 412   to[0] = from[0];
 413   to[1] = from[1];
 414   to[2] = from[2];
 415   to[3] = from[3];
 416 }
 417
 418 void
 419 z8k_pop_frame ()
 420 {
 421 }
 422
 423 struct cmd_list_element *setmemorylist;
 424
 425 void
 426 z8k_set_pointer_size (newsize)
 427      int newsize;
 428 {
 429   static int oldsize = 0;
 430
 431   if (oldsize != newsize)
 432     {
 433       printf ("pointer size set to %d bits\n", newsize);
 434       oldsize = newsize;
 435       if (newsize == 32)
 436         {
 437           BIG = 1;
 438         }
 439       else
 440         {
 441           BIG = 0;
 442         }
 443       _initialize_gdbtypes ();
 444     }
 445 }
 446
 447 static void
 448 segmented_command (args, from_tty)
 449      char *args;
 450      int from_tty;
 451 {
 452   z8k_set_pointer_size (32);
 453 }
 454
 455 static void
 456 unsegmented_command (args, from_tty)
 457      char *args;
 458      int from_tty;
 459 {
 460   z8k_set_pointer_size (16);
 461
 462 }
 463
 464 static void
 465 set_memory (args, from_tty)
 466      char *args;
 467      int from_tty;
 468 {
 469   printf ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 470   help_list (setmemorylist, "set memory ", -1, stdout);
 471 }
 472
 473 _initialize_z8ktdep ()
 474 {
 475   add_prefix_cmd ("memory", no_class, set_memory,
 476                   "set the memory model", &setmemorylist, "set memory ", 0,
 477                   &setlist);
 478   add_cmd ("segmented", class_support, segmented_command,
 479            "Set segmented memory model.", &setmemorylist);
 480   add_cmd ("unsegmented", class_support, unsegmented_command,
 481            "Set unsegmented memory model.", &setmemorylist);
 482
 483 }