gdb/z8k-tdep.c

   1 /* Target-machine dependent code for Zilog Z8000, for GDB.
   2    Copyright (C) 1992 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
  26 #include "defs.h"
  27 #include "frame.h"
  28 #include "obstack.h"
  29 #include "symtab.h"
  30 #include "gdbtypes.h"
  31
  32
  33 /* Return the saved PC from this frame.
  34
  35    If the frame has a memory copy of SRP_REGNUM, use that.  If not,
  36    just use the register SRP_REGNUM itself.  */
  37
  38 CORE_ADDR
  39 frame_saved_pc (frame)
  40 FRAME frame;
  41 {
  42   return ( read_memory_pointer(frame->frame+(BIG ? 4 : 2)));
  43 }
  44
  45 #define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
  46 #define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
  47 #define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
  48 #define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
  49 #define IS_SUB2_SP(x) (x==0x1b87)
  50 #define IS_MOVK_R5(x) (x==0x7905)
  51 #define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
  52 #define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
  53
  54
  55 /* work out how much local space is on the stack and
  56    return the pc pointing to the first push */
  57
  58 static
  59 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
  84 int
  85 examine_frame(pc, regs, sp)
  86 CORE_ADDR pc;
  87 struct frame_saved_regs *regs;
  88 CORE_ADDR sp;
  89 {
  90  int w = read_memory_short(pc);
  91  int offset = 0;
  92  int regno;
  93
  94
  95
  96  for (regno = 0; regno < NUM_REGS; regno++)
  97   regs->regs[regno] = 0;
  98
  99   while  (IS_PUSHW(w) || IS_PUSHL(w))
 100   {
 101     /* work out which register is being pushed to where */
 102     if (IS_PUSHL(w))
 103     {
 104       regs->regs[w & 0xf] = offset;
 105       regs->regs[(w & 0xf) + 1] = offset +2;
 106       offset += 4;
 107     }
 108     else {
 109       regs->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->regs[FP_REGNUM] = sp;
 127  }
 128  else
 129  {
 130    /* This one didn't have an fp, we'll fake it up */
 131    regs->regs[SP_REGNUM] = sp;
 132  }
 133  /* stack pointer contains address of next frame */
 134 /*  regs->regs[fp_regnum()] = fp;*/
 135   regs->regs[SP_REGNUM] = sp;
 136   return pc;
 137 }
 138
 139 CORE_ADDR z8k_skip_prologue(start_pc)
 140 CORE_ADDR start_pc;
 141 {
 142   struct frame_saved_regs dummy;
 143   return examine_frame(start_pc, &dummy, 0);
 144 }
 145
 146 CORE_ADDR addr_bits_remove(x)
 147 CORE_ADDR x;
 148 {
 149   return x & PTR_MASK;
 150 }
 151
 152 read_memory_pointer(x)
 153 CORE_ADDR x;
 154 {
 155
 156 return read_memory_integer(ADDR_BITS_REMOVE(x), BIG ? 4 : 2);
 157 }
 158
 159 FRAME_ADDR
 160 frame_chain (thisframe)
 161      FRAME thisframe;
 162 {
 163   if (thisframe->prev == 0)
 164   {
 165     /* This is the top of the stack, let's get the sp for real */
 166   }
 167   if (!inside_entry_file ((thisframe)->pc))
 168   {
 169 return     read_memory_pointer ((thisframe)->frame);
 170   }
 171
 172   return 0;
 173 }
 174
 175 init_frame_pc() { abort(); }
 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 get_frame_saved_regs(frame_info, frame_saved_regs)
 184      struct frame_info *frame_info;
 185      struct frame_saved_regs *frame_saved_regs;
 186
 187 {
 188 CORE_ADDR pc;
 189 int w;
 190 bzero(frame_saved_regs, sizeof(*frame_saved_regs));
 191 pc = get_pc_function_start(frame_info->pc);
 192
 193 /* wander down the instruction stream */
 194 examine_frame(pc, frame_saved_regs, frame_info->frame);
 195
 196 }
 197
 198
 199 extract_return_value(valtype, regbuf, valbuf)
 200 struct type *valtype;
 201 char regbuf[REGISTER_BYTES];
 202 char *valbuf;
 203 {
 204   bcopy(regbuf + REGISTER_BYTE(2), valbuf, TYPE_LENGTH(valtype));
 205 }
 206 void z8k_push_dummy_frame() { abort(); }
 207
 208 int print_insn(memaddr, stream)
 209 CORE_ADDR memaddr;
 210 FILE *stream;
 211 {
 212   char temp[20];
 213   read_memory (memaddr, temp, 20);
 214   if (BIG) {
 215     return print_insn_z8001(memaddr, temp, stream);
 216   }
 217   else {
 218     return print_insn_z8002(memaddr, temp, stream);
 219   }
 220 }
 221
 222 void
 223 store_return_value()
 224 {
 225 abort();
 226 }
 227 void
 228 store_struct_return() { abort(); }
 229
 230
 231
 232 /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
 233    is not the address of a valid instruction, the address of the next
 234    instruction beyond ADDR otherwise.  *PWORD1 receives the first word
 235    of the instruction.*/
 236
 237
 238 CORE_ADDR
 239 NEXT_PROLOGUE_INSN(addr, lim, pword1)
 240 CORE_ADDR addr;
 241 CORE_ADDR lim;
 242 short *pword1;
 243 {
 244   if (addr < lim+8)
 245   {
 246     read_memory (addr, pword1, sizeof(*pword1));
 247     SWAP_TARGET_AND_HOST (pword1, sizeof (short));
 248     return addr + 2;
 249   }
 250
 251   return 0;
 252
 253 }
 254
 255
 256 /* Put here the code to store, into a struct frame_saved_regs,
 257    the addresses of the saved registers of frame described by FRAME_INFO.
 258    This includes special registers such as pc and fp saved in special
 259    ways in the stack frame.  sp is even more special:
 260    the address we return for it IS the sp for the next frame.
 261
 262    We cache the result of doing this in the frame_cache_obstack, since
 263    it is fairly expensive.  */
 264
 265 void
 266 frame_find_saved_regs (fip, fsrp)
 267      struct frame_info *fip;
 268      struct frame_saved_regs *fsrp;
 269 {
 270   int locals;
 271   CORE_ADDR pc;
 272   CORE_ADDR adr;
 273   int i;
 274
 275   memset (fsrp, 0, sizeof *fsrp);
 276
 277   pc = skip_adjust(get_pc_function_start (fip->pc), &locals);
 278
 279  {
 280    adr = fip->frame - locals;
 281    for (i = 0; i < 8; i++)
 282    {
 283      int word = read_memory_short(pc);
 284      pc += 2 ;
 285      if (IS_PUSHL(word)) {
 286        fsrp->regs[word & 0xf] = adr;
 287        fsrp->regs[(word & 0xf) + 1] = adr - 2;
 288        adr -= 4;
 289      }
 290      else if (IS_PUSHW(word)) {
 291        fsrp->regs[word & 0xf] = adr;
 292        adr -= 2;
 293      }
 294      else
 295       break;
 296    }
 297
 298  }
 299
 300   fsrp->regs[PC_REGNUM] = fip->frame + 4;
 301   fsrp->regs[FP_REGNUM] = fip->frame;
 302
 303 }
 304
 305 void
 306 addr_bits_set() { abort(); }
 307
 308 int
 309 saved_pc_after_call()
 310 {
 311   return addr_bits_remove(read_memory_integer(read_register(SP_REGNUM), PTR_SIZE));
 312 }
 313
 314 void
 315 print_register_hook(regno)
 316 int regno;
 317 {
 318
 319   if ((regno & 1)==0 && regno < 16)
 320   {
 321     unsigned    short l[2];
 322     read_relative_register_raw_bytes(regno, (char *)(l+0));
 323     read_relative_register_raw_bytes(regno+1, (char *)(l+1));
 324     printf("\t");
 325     printf("%04x%04x", l[0],l[1]);
 326   }
 327
 328   if ((regno & 3)== 0 && regno < 16)
 329   {
 330     unsigned    short l[4];
 331     read_relative_register_raw_bytes(regno, l+0);
 332     read_relative_register_raw_bytes(regno+1, l+1);
 333     read_relative_register_raw_bytes(regno+2, l+2);
 334     read_relative_register_raw_bytes(regno+3, l+3);
 335
 336     printf("\t");
 337     printf("%04x%04x%04x%04x", l[0],l[1],l[2],l[3]);
 338   }
 339   if (regno == 15)
 340   {
 341     unsigned    short  rval;
 342     int i;
 343     read_relative_register_raw_bytes(regno, (char *)(&rval));
 344
 345     printf("\n");
 346     for (i = 0; i < 10; i+=2)   {
 347       printf("(sp+%d=%04x)",i, read_memory_short(rval+i));
 348     }
 349   }
 350
 351 }
 352
 353
 354 void
 355 register_convert_to_virtual(regnum, from, to)
 356 unsigned char *from;
 357 unsigned char *to;
 358 {
 359     to[0] = from[0];
 360     to[1] = from[1];
 361     to[2] = from[2];
 362     to[3] = from[3];
 363 }
 364
 365 void
 366 register_convert_to_raw(regnum, to, from)
 367 char *to;
 368 char *from;
 369 {
 370     to[0] = from[0];
 371     to[1] = from[1];
 372     to[2] = from[2];
 373     to[3] = from[3];
 374 }
 375
 376
 377
 378 void z8k_pop_frame() {  }