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 #include "value.h" /* For read_register() */
  36
  37
  38 static int read_memory_pointer (CORE_ADDR x);
  39
  40 /* Return the saved PC from this frame.
  41
  42    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  43    just use the register SRP_REGNUM itself.  */
  44
  45 CORE_ADDR
  46 z8k_frame_saved_pc (struct frame_info *frame)
  47 {
  48   return read_memory_pointer (frame->frame + (BIG ? 4 : 2));
  49 }
  50
  51 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  52 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  53 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  54 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  55 #define IS_SUB2_SP(x) (x==0x1b87)
  56 #define IS_MOVK_R5(x) (x==0x7905)
  57 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  58 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  59
  60 /* work out how much local space is on the stack and
  61    return the pc pointing to the first push */
  62
  63 static CORE_ADDR
  64 skip_adjust (CORE_ADDR pc, int *size)
  65 {
  66   *size = 0;
  67
  68   if (IS_PUSH_FP (read_memory_short (pc))
  69       && IS_MOV_SP_FP (read_memory_short (pc + 2)))
  70     {
  71       /* This is a function with an explict frame pointer */
  72       pc += 4;
  73       *size += 2;               /* remember the frame pointer */
  74     }
  75
  76   /* remember any stack adjustment */
  77   if (IS_SUB_SP (read_memory_short (pc)))
  78     {
  79       *size += read_memory_short (pc + 2);
  80       pc += 4;
  81     }
  82   return pc;
  83 }
  84
  85 static CORE_ADDR examine_frame (CORE_ADDR, CORE_ADDR * regs, CORE_ADDR);
  86 static CORE_ADDR
  87 examine_frame (CORE_ADDR pc, CORE_ADDR *regs, 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[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[w & 0xf] = offset;
 102           regs[(w & 0xf) + 1] = offset + 2;
 103           offset += 4;
 104         }
 105       else
 106         {
 107           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[FP_REGNUM] = sp;
 125     }
 126   else
 127     {
 128       /* This one didn't have an fp, we'll fake it up */
 129       regs[SP_REGNUM] = sp;
 130     }
 131   /* stack pointer contains address of next frame */
 132   /*  regs[fp_regnum()] = fp; */
 133   regs[SP_REGNUM] = sp;
 134   return pc;
 135 }
 136
 137 CORE_ADDR
 138 z8k_skip_prologue (CORE_ADDR start_pc)
 139 {
 140   CORE_ADDR dummy[NUM_REGS];
 141
 142   return examine_frame (start_pc, dummy, 0);
 143 }
 144
 145 CORE_ADDR
 146 z8k_addr_bits_remove (CORE_ADDR addr)
 147 {
 148   return (addr & PTR_MASK);
 149 }
 150
 151 static int
 152 read_memory_pointer (CORE_ADDR x)
 153 {
 154   return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
 155 }
 156
 157 CORE_ADDR
 158 z8k_frame_chain (struct frame_info *thisframe)
 159 {
 160   if (thisframe->prev == 0)
 161     {
 162       /* This is the top of the stack, let's get the sp for real */
 163     }
 164   if (!inside_entry_file (thisframe->pc))
 165     {
 166       return read_memory_pointer (thisframe->frame);
 167     }
 168   return 0;
 169 }
 170
 171 void
 172 init_frame_pc (void)
 173 {
 174   internal_error (__FILE__, __LINE__, "failed internal consistency check");
 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 z8k_frame_init_saved_regs (struct frame_info *frame_info)
 185 {
 186   CORE_ADDR pc;
 187   int w;
 188
 189   frame_saved_regs_zalloc (frame_info);
 190   pc = get_pc_function_start (frame_info->pc);
 191
 192   /* wander down the instruction stream */
 193   examine_frame (pc, frame_info->saved_regs, frame_info->frame);
 194
 195 }
 196
 197 void
 198 z8k_push_dummy_frame (void)
 199 {
 200   internal_error (__FILE__, __LINE__, "failed internal consistency check");
 201 }
 202
 203 int
 204 gdb_print_insn_z8k (bfd_vma memaddr, disassemble_info *info)
 205 {
 206   if (BIG)
 207     return print_insn_z8001 (memaddr, info);
 208   else
 209     return print_insn_z8002 (memaddr, info);
 210 }
 211
 212 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 213    is not the address of a valid instruction, the address of the next
 214    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 215    of the instruction. */
 216
 217 CORE_ADDR
 218 NEXT_PROLOGUE_INSN (CORE_ADDR addr, CORE_ADDR lim, short *pword1)
 219 {
 220   char buf[2];
 221   if (addr < lim + 8)
 222     {
 223       read_memory (addr, buf, 2);
 224       *pword1 = extract_signed_integer (buf, 2);
 225
 226       return addr + 2;
 227     }
 228   return 0;
 229 }
 230
 231 #if 0
 232 /* Put here the code to store, into a struct frame_saved_regs,
 233    the addresses of the saved registers of frame described by FRAME_INFO.
 234    This includes special registers such as pc and fp saved in special
 235    ways in the stack frame.  sp is even more special:
 236    the address we return for it IS the sp for the next frame.
 237
 238    We cache the result of doing this in the frame_cache_obstack, since
 239    it is fairly expensive.  */
 240
 241 void
 242 frame_find_saved_regs (struct frame_info *fip, struct frame_saved_regs *fsrp)
 243 {
 244   int locals;
 245   CORE_ADDR pc;
 246   CORE_ADDR adr;
 247   int i;
 248
 249   memset (fsrp, 0, sizeof *fsrp);
 250
 251   pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
 252
 253   {
 254     adr = FRAME_FP (fip) - locals;
 255     for (i = 0; i < 8; i++)
 256       {
 257         int word = read_memory_short (pc);
 258
 259         pc += 2;
 260         if (IS_PUSHL (word))
 261           {
 262             fsrp->regs[word & 0xf] = adr;
 263             fsrp->regs[(word & 0xf) + 1] = adr - 2;
 264             adr -= 4;
 265           }
 266         else if (IS_PUSHW (word))
 267           {
 268             fsrp->regs[word & 0xf] = adr;
 269             adr -= 2;
 270           }
 271         else
 272           break;
 273       }
 274
 275   }
 276
 277   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 278   fsrp->regs[FP_REGNUM] = fip->frame;
 279
 280 }
 281 #endif
 282
 283 int
 284 z8k_saved_pc_after_call (struct frame_info *frame)
 285 {
 286   return ADDR_BITS_REMOVE
 287     (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
 288 }
 289
 290
 291 void
 292 extract_return_value (struct type *type, char *regbuf, char *valbuf)
 293 {
 294   int b;
 295   int len = TYPE_LENGTH (type);
 296
 297   for (b = 0; b < len; b += 2)
 298     {
 299       int todo = len - b;
 300
 301       if (todo > 2)
 302         todo = 2;
 303       memcpy (valbuf + b, regbuf + b, todo);
 304     }
 305 }
 306
 307 void
 308 write_return_value (struct type *type, char *valbuf)
 309 {
 310   int reg;
 311   int len;
 312
 313   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 314     write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
 315 }
 316
 317 void
 318 store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
 319 {
 320   write_register (2, addr);
 321 }
 322
 323
 324 void
 325 z8k_print_register_hook (int regno)
 326 {
 327   if ((regno & 1) == 0 && regno < 16)
 328     {
 329       unsigned short l[2];
 330
 331       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 332       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 333       printf_unfiltered ("\t");
 334       printf_unfiltered ("%04x%04x", l[0], l[1]);
 335     }
 336
 337   if ((regno & 3) == 0 && regno < 16)
 338     {
 339       unsigned short l[4];
 340
 341       read_relative_register_raw_bytes (regno, (char *) (l + 0));
 342       read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
 343       read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
 344       read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
 345
 346       printf_unfiltered ("\t");
 347       printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
 348     }
 349   if (regno == 15)
 350     {
 351       unsigned short rval;
 352       int i;
 353
 354       read_relative_register_raw_bytes (regno, (char *) (&rval));
 355
 356       printf_unfiltered ("\n");
 357       for (i = 0; i < 10; i += 2)
 358         {
 359           printf_unfiltered ("(sp+%d=%04x)", i,
 360                              (unsigned int)read_memory_short (rval + i));
 361         }
 362     }
 363
 364 }
 365
 366 void
 367 z8k_pop_frame (void)
 368 {
 369 }
 370
 371 struct cmd_list_element *setmemorylist;
 372
 373 void
 374 z8k_set_pointer_size (int newsize)
 375 {
 376   static int oldsize = 0;
 377
 378   if (oldsize != newsize)
 379     {
 380       printf_unfiltered ("pointer size set to %d bits\n", newsize);
 381       oldsize = newsize;
 382       if (newsize == 32)
 383         {
 384           BIG = 1;
 385         }
 386       else
 387         {
 388           BIG = 0;
 389         }
 390       /* FIXME: This code should be using the GDBARCH framework to
 391          handle changed type sizes.  If this problem is ever fixed
 392          (the direct reference to _initialize_gdbtypes() below
 393          eliminated) then Makefile.in should be updated so that
 394          z8k-tdep.c is again compiled with -Werror. */
 395       _initialize_gdbtypes ();
 396     }
 397 }
 398
 399 static void
 400 segmented_command (char *args, int from_tty)
 401 {
 402   z8k_set_pointer_size (32);
 403 }
 404
 405 static void
 406 unsegmented_command (char *args, int from_tty)
 407 {
 408   z8k_set_pointer_size (16);
 409 }
 410
 411 static void
 412 set_memory (char *args, int from_tty)
 413 {
 414   printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
 415   help_list (setmemorylist, "set memory ", -1, gdb_stdout);
 416 }
 417
 418 void
 419 _initialize_z8ktdep (void)
 420 {
 421   tm_print_insn = gdb_print_insn_z8k;
 422
 423   add_prefix_cmd ("memory", no_class, set_memory,
 424                   "set the memory model", &setmemorylist, "set memory ", 0,
 425                   &setlist);
 426   add_cmd ("segmented", class_support, segmented_command,
 427            "Set segmented memory model.", &setmemorylist);
 428   add_cmd ("unsegmented", class_support, unsegmented_command,
 429            "Set unsegmented memory model.", &setmemorylist);
 430
 431 }