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