gdb/w65-tdep.c

   1 /* Target-machine dependent code for WDC-65816, for GDB.
   2    Copyright (C) 1995 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
  33
  34 /* Return the saved PC from this frame. */
  35
  36
  37 CORE_ADDR
  38 w65_frame_saved_pc (frame)
  39      struct frame_info *frame;
  40 {
  41   return (read_memory_integer (frame->frame + 2, 4) & 0xffffff);
  42 }
  43
  44 CORE_ADDR
  45 addr_bits_remove (x)
  46      CORE_ADDR x;
  47 {
  48   return x;
  49 }
  50
  51 read_memory_pointer (x)
  52      CORE_ADDR x;
  53 {
  54   return read_memory_integer (ADDR_BITS_REMOVE (x), 4);
  55 }
  56
  57 init_frame_pc ()
  58 {
  59   abort ();
  60 }
  61
  62 void
  63 w65_push_dummy_frame ()
  64 {
  65   abort ();
  66 }
  67
  68 /* Put here the code to store, into a struct frame_saved_regs,
  69    the addresses of the saved registers of frame described by FRAME_INFO.
  70    This includes special registers such as pc and fp saved in special
  71    ways in the stack frame.  sp is even more special:
  72    the address we return for it IS the sp for the next frame.
  73
  74    We cache the result of doing this in the frame_cache_obstack, since
  75    it is fairly expensive.  */
  76
  77 void
  78 frame_find_saved_regs (fip, fsrp)
  79      struct frame_info *fip;
  80      struct frame_saved_regs *fsrp;
  81 {
  82   int locals;
  83   CORE_ADDR pc;
  84   CORE_ADDR adr;
  85   int i;
  86
  87   memset (fsrp, 0, sizeof *fsrp);
  88 }
  89
  90 int
  91 saved_pc_after_call ()
  92 {
  93   int sp = read_register (SP_REGNUM);
  94   int val = read_memory_integer (sp + 1, 4);
  95   return ADDR_BITS_REMOVE (val);
  96 }
  97
  98
  99 extract_return_value (type, regbuf, valbuf)
 100      struct type *type;
 101      char *regbuf;
 102      char *valbuf;
 103 {
 104   int b;
 105   int len = TYPE_LENGTH (type);
 106
 107   for (b = 0; b < len; b += 2)
 108     {
 109       int todo = len - b;
 110       if (todo > 2)
 111         todo = 2;
 112       memcpy (valbuf + b, regbuf + b, todo);
 113     }
 114 }
 115
 116 void
 117 write_return_value (type, valbuf)
 118      struct type *type;
 119      char *valbuf;
 120 {
 121   int reg;
 122   int len;
 123   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 124     {
 125       write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
 126     }
 127 }
 128
 129 void
 130 store_struct_return (addr, sp)
 131      CORE_ADDR addr;
 132      CORE_ADDR sp;
 133 {
 134   write_register (2, addr);
 135 }
 136
 137 void
 138 w65_pop_frame ()
 139 {
 140 }
 141
 142 init_extra_frame_info ()
 143 {
 144 }
 145
 146 pop_frame ()
 147 {
 148 }
 149
 150 w65_frame_chain (thisframe)
 151      struct frame_info *thisframe;
 152 {
 153   return 0xffff & read_memory_integer ((thisframe)->frame, 2);
 154 }
 155
 156 static int
 157 gb (x)
 158 {
 159   return read_memory_integer (x, 1) & 0xff;
 160 }
 161
 162 extern CORE_ADDR
 163 w65_skip_prologue (pc)
 164      CORE_ADDR pc;
 165 {
 166   CORE_ADDR too_far = pc + 20;
 167
 168   /* looking for bits of the prologue, we can expect to
 169      see this in a frameful function:
 170
 171      stack adjust:
 172
 173      3B                 tsc
 174      1A                 inc a
 175      18                 clc
 176      69E2FF             adc     #0xffe2
 177      3A                 dec a
 178      1B                 tcs
 179      1A                 inc a
 180
 181      link:
 182
 183      A500               lda     <r15
 184      48                 pha
 185      3B                 tsc
 186      1a                 inc     a
 187      8500               sta     <r15
 188
 189    */
 190
 191 #define TSC  0x3b
 192 #define TCS  0x1b
 193 #define INCA 0x1a
 194 #define PHA  0x48
 195 #define LDADIR 0xa5
 196 #define STADIR 0x85
 197
 198   /* Skip a stack adjust - any area between a tsc and tcs */
 199   if (gb (pc) == TSC)
 200     {
 201       while (pc < too_far && gb (pc) != TCS)
 202         {
 203           pc++;
 204         }
 205       pc++;
 206       /* Skip a stupid inc a */
 207       if (gb (pc) == INCA)
 208         pc++;
 209
 210     }
 211   /* Stack adjust can also be done with n pha's */
 212   while (gb (pc) == PHA)
 213     pc++;
 214
 215   /* Skip a link - that's a ld/ph/tsc/inc/sta */
 216
 217   if (gb (pc) == LDADIR
 218       && gb (pc + 5) == STADIR
 219       && gb (pc + 1) == gb (pc + 6)
 220       && gb (pc + 2) == PHA
 221       && gb (pc + 3) == TSC
 222       && gb (pc + 4) == INCA)
 223     {
 224       pc += 7;
 225     }
 226
 227   return pc;
 228 }
 229
 230
 231 register_raw_size (n)
 232 {
 233   return sim_reg_size (n);
 234 }
 235
 236
 237 void
 238 print_register_hook (regno)
 239 {
 240   if (regno == P_REGNUM)
 241     {
 242       /* CCR register */
 243
 244       int C, Z, N, V, I, D, X, M;
 245       unsigned char b[1];
 246       unsigned char l;
 247
 248       read_relative_register_raw_bytes (regno, b);
 249       l = b[0];
 250       printf_unfiltered ("\t");
 251       C = (l & 0x1) != 0;
 252       Z = (l & 0x2) != 0;
 253       I = (l & 0x4) != 0;
 254       D = (l & 0x8) != 0;
 255       X = (l & 0x10) != 0;
 256       M = (l & 0x20) != 0;
 257       V = (l & 0x40) != 0;
 258       N = (l & 0x80) != 0;
 259
 260       printf_unfiltered ("N-%d ", N);
 261       printf_unfiltered ("V-%d ", V);
 262       printf_unfiltered ("M-%d ", M);
 263       printf_unfiltered ("X-%d ", X);
 264       printf_unfiltered ("D-%d ", D);
 265       printf_unfiltered ("I-%d ", I);
 266       printf_unfiltered ("Z-%d ", Z);
 267       printf_unfiltered ("C-%d ", C);
 268       if ((C | Z) == 0)
 269         printf_unfiltered ("u> ");
 270       if ((C | Z) == 1)
 271         printf_unfiltered ("u<= ");
 272       if ((C == 0))
 273         printf_unfiltered ("u>= ");
 274       if (C == 1)
 275         printf_unfiltered ("u< ");
 276       if (Z == 0)
 277         printf_unfiltered ("!= ");
 278       if (Z == 1)
 279         printf_unfiltered ("== ");
 280       if ((N ^ V) == 0)
 281         printf_unfiltered (">= ");
 282       if ((N ^ V) == 1)
 283         printf_unfiltered ("< ");
 284       if ((Z | (N ^ V)) == 0)
 285         printf_unfiltered ("> ");
 286       if ((Z | (N ^ V)) == 1)
 287         printf_unfiltered ("<= ");
 288     }
 289 }
 290
 291 void
 292 _initialize_w65_tdep ()
 293 {
 294   tm_print_insn = print_insn_w65;
 295 }