gdb/w65-tdep.c

   1 /* Target-machine dependent code for WDC-65816, for GDB.
   2    Copyright 1995, 1996, 2000, 2001 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 #include "regcache.h"
  35
  36 /* Return the saved PC from this frame. */
  37
  38
  39 CORE_ADDR
  40 w65_frame_saved_pc (struct frame_info *frame)
  41 {
  42   return (read_memory_integer (frame->frame + 2, 4) & 0xffffff);
  43 }
  44
  45 CORE_ADDR
  46 w65_addr_bits_remove (CORE_ADDR addr)
  47 {
  48   return ((addr) & 0xffffff);
  49 }
  50
  51 read_memory_pointer (CORE_ADDR x)
  52 {
  53   return read_memory_integer (ADDR_BITS_REMOVE (x), 4);
  54 }
  55
  56 init_frame_pc (void)
  57 {
  58   internal_error (__FILE__, __LINE__, "failed internal consistency check");
  59 }
  60
  61 void
  62 w65_push_dummy_frame (void)
  63 {
  64   internal_error (__FILE__, __LINE__, "failed internal consistency check");
  65 }
  66
  67 /* Put here the code to store, into a struct frame_saved_regs,
  68    the addresses of the saved registers of frame described by FRAME_INFO.
  69    This includes special registers such as pc and fp saved in special
  70    ways in the stack frame.  sp is even more special:
  71    the address we return for it IS the sp for the next frame.
  72
  73    We cache the result of doing this in the frame_cache_obstack, since
  74    it is fairly expensive.  */
  75
  76 void
  77 frame_find_saved_regs (struct frame_info *fip, struct frame_saved_regs *fsrp)
  78 {
  79   int locals;
  80   CORE_ADDR pc;
  81   CORE_ADDR adr;
  82   int i;
  83
  84   memset (fsrp, 0, sizeof *fsrp);
  85 }
  86
  87 int
  88 saved_pc_after_call (void)
  89 {
  90   int sp = read_register (SP_REGNUM);
  91   int val = read_memory_integer (sp + 1, 4);
  92   return ADDR_BITS_REMOVE (val);
  93 }
  94
  95
  96 extract_return_value (struct type *type, char *regbuf, char *valbuf)
  97 {
  98   int b;
  99   int len = TYPE_LENGTH (type);
 100
 101   for (b = 0; b < len; b += 2)
 102     {
 103       int todo = len - b;
 104       if (todo > 2)
 105         todo = 2;
 106       memcpy (valbuf + b, regbuf + b, todo);
 107     }
 108 }
 109
 110 void
 111 write_return_value (struct type *type, char *valbuf)
 112 {
 113   int reg;
 114   int len;
 115   for (len = 0; len < TYPE_LENGTH (type); len += 2)
 116     {
 117       write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
 118     }
 119 }
 120
 121 void
 122 store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
 123 {
 124   write_register (2, addr);
 125 }
 126
 127 void
 128 w65_pop_frame (void)
 129 {
 130 }
 131
 132 init_extra_frame_info (void)
 133 {
 134 }
 135
 136 pop_frame (void)
 137 {
 138 }
 139
 140 w65_frame_chain (struct frame_info *thisframe)
 141 {
 142   return 0xffff & read_memory_integer ((thisframe)->frame, 2);
 143 }
 144
 145 static int
 146 gb (int x)
 147 {
 148   return read_memory_integer (x, 1) & 0xff;
 149 }
 150
 151 extern CORE_ADDR
 152 w65_skip_prologue (CORE_ADDR pc)
 153 {
 154   CORE_ADDR too_far = pc + 20;
 155
 156   /* looking for bits of the prologue, we can expect to
 157      see this in a frameful function:
 158
 159      stack adjust:
 160
 161      3B                 tsc
 162      1A                 inc a
 163      18                 clc
 164      69E2FF             adc     #0xffe2
 165      3A                 dec a
 166      1B                 tcs
 167      1A                 inc a
 168
 169      link:
 170
 171      A500               lda     <r15
 172      48                 pha
 173      3B                 tsc
 174      1a                 inc     a
 175      8500               sta     <r15
 176
 177    */
 178
 179 #define TSC  0x3b
 180 #define TCS  0x1b
 181 #define INCA 0x1a
 182 #define PHA  0x48
 183 #define LDADIR 0xa5
 184 #define STADIR 0x85
 185
 186   /* Skip a stack adjust - any area between a tsc and tcs */
 187   if (gb (pc) == TSC)
 188     {
 189       while (pc < too_far && gb (pc) != TCS)
 190         {
 191           pc++;
 192         }
 193       pc++;
 194       /* Skip a stupid inc a */
 195       if (gb (pc) == INCA)
 196         pc++;
 197
 198     }
 199   /* Stack adjust can also be done with n pha's */
 200   while (gb (pc) == PHA)
 201     pc++;
 202
 203   /* Skip a link - that's a ld/ph/tsc/inc/sta */
 204
 205   if (gb (pc) == LDADIR
 206       && gb (pc + 5) == STADIR
 207       && gb (pc + 1) == gb (pc + 6)
 208       && gb (pc + 2) == PHA
 209       && gb (pc + 3) == TSC
 210       && gb (pc + 4) == INCA)
 211     {
 212       pc += 7;
 213     }
 214
 215   return pc;
 216 }
 217
 218
 219 register_raw_size (int n)
 220 {
 221   return sim_reg_size (n);
 222 }
 223
 224
 225 void
 226 print_register_hook (int regno)
 227 {
 228   if (regno == P_REGNUM)
 229     {
 230       /* CCR register */
 231
 232       int C, Z, N, V, I, D, X, M;
 233       unsigned char b[1];
 234       unsigned char l;
 235
 236       read_relative_register_raw_bytes (regno, b);
 237       l = b[0];
 238       printf_unfiltered ("\t");
 239       C = (l & 0x1) != 0;
 240       Z = (l & 0x2) != 0;
 241       I = (l & 0x4) != 0;
 242       D = (l & 0x8) != 0;
 243       X = (l & 0x10) != 0;
 244       M = (l & 0x20) != 0;
 245       V = (l & 0x40) != 0;
 246       N = (l & 0x80) != 0;
 247
 248       printf_unfiltered ("N-%d ", N);
 249       printf_unfiltered ("V-%d ", V);
 250       printf_unfiltered ("M-%d ", M);
 251       printf_unfiltered ("X-%d ", X);
 252       printf_unfiltered ("D-%d ", D);
 253       printf_unfiltered ("I-%d ", I);
 254       printf_unfiltered ("Z-%d ", Z);
 255       printf_unfiltered ("C-%d ", C);
 256       if ((C | Z) == 0)
 257         printf_unfiltered ("u> ");
 258       if ((C | Z) == 1)
 259         printf_unfiltered ("u<= ");
 260       if ((C == 0))
 261         printf_unfiltered ("u>= ");
 262       if (C == 1)
 263         printf_unfiltered ("u< ");
 264       if (Z == 0)
 265         printf_unfiltered ("!= ");
 266       if (Z == 1)
 267         printf_unfiltered ("== ");
 268       if ((N ^ V) == 0)
 269         printf_unfiltered (">= ");
 270       if ((N ^ V) == 1)
 271         printf_unfiltered ("< ");
 272       if ((Z | (N ^ V)) == 0)
 273         printf_unfiltered ("> ");
 274       if ((Z | (N ^ V)) == 1)
 275         printf_unfiltered ("<= ");
 276     }
 277 }
 278
 279 void
 280 _initialize_w65_tdep (void)
 281 {
 282   tm_print_insn = print_insn_w65;
 283 }