dis6502.c

linux下的MPEG1

/*
** Nofrendo (c) 1998-2000 Matthew Conte ([e-mail])
**
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of version 2 of the GNU Library General 
** Public License as published by the Free Software Foundation.
**
** This program is distributed in the hope that it will be useful, 
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
** Library General Public License for more details.  To obtain a 
** copy of the GNU Library General Public License, write to the Free 
** Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
**
** Any permitted reproduction of these routines, in whole or in part,
** must bear this legend.
**
**
** dis6502.c
**
** 6502 disassembler based on code from John Saeger
** $Id: dis6502.c,v 1.2 2003/12/05 15:55:01 f1rmb Exp $
*/

#include "types.h"
#include "log.h"
#include "nes6502.h"
#include "dis6502.h"

#ifdef NES6502_DEBUG

/* addressing modes */
enum { _imp, _acc, _rel, _imm, _abs, _abs_x, _abs_y, _zero, _zero_x, _zero_y, _ind, _ind_x, _ind_y };

/* keep a filthy local copy of PC to
** reduce the amount of parameter passing
*/
static uint32 pc_reg;


static uint8 dis_op8(void)
{
   return (nes6502_getbyte(pc_reg + 1));
}

static uint16 dis_op16(void)
{
   return (nes6502_getbyte(pc_reg + 1) + (nes6502_getbyte(pc_reg + 2) << 8));
}

static void dis_show_ind(void)
{
   log_printf("(%04X)  ", dis_op16());
}

static void dis_show_ind_x(void)
{
   log_printf("(%02X,x)  ", dis_op8());
}

static void dis_show_ind_y(void)
{
   log_printf("(%02X),y  ", dis_op8());
}

static void dis_show_zero_x(void)
{
   log_printf(" %02X,x   ", dis_op8());
}

static void dis_show_zero_y(void)
{
   log_printf(" %02X,y   ", dis_op8());
}

static void dis_show_abs_y(void)
{
   log_printf(" %04X,y ", dis_op16());
}

static void dis_show_abs_x(void)
{
   log_printf(" %04X,x ", dis_op16());
}

static void dis_show_zero(void)
{
   log_printf(" %02X     ", dis_op8());
}

static void dis_show_abs(void)
{
   log_printf(" %04X   ", dis_op16());
}

static void dis_show_immediate(void)
{
   log_printf("#%02X     ", dis_op8());
}

static void dis_show_acc(void)
{
   log_printf(" a      ");
}

static void dis_show_relative(void)
{
   int target;

   target = (int8) dis_op8();
   target += (pc_reg + 2);
   log_printf(" %04X   ", target);
}

static void dis_show_code(int optype)
{
   log_printf("%02X ", nes6502_getbyte(pc_reg));

   switch (optype)
   {
   case _imp:
   case _acc: 
      log_printf("      ");
      break;

   case _rel:
   case _imm:
   case _zero:
   case _zero_x:
      log_printf("%02X    ", nes6502_getbyte(pc_reg + 1));
      break;

   case _abs:
   case _abs_x:
   case _abs_y:
   case _ind:
   case _ind_x:
   case _ind_y:
      log_printf("%02X %02X ", nes6502_getbyte(pc_reg + 1), nes6502_getbyte(pc_reg + 2));
      break;
   }
}

static void dis_show_op(char *opstr, int optype)
{
   dis_show_code(optype);
   log_printf("%s ", opstr);

   switch(optype)
   {
   case _imp:     log_printf("        "); break;
   case _acc:     dis_show_acc();         break;
   case _rel:     dis_show_relative();    break;
   case _imm:     dis_show_immediate();   break;
   case _abs:     dis_show_abs();         break;
   case _abs_x:   dis_show_abs_x();       break;
   case _abs_y:   dis_show_abs_y();       break;
   case _zero:    dis_show_zero();        break;
   case _zero_x:  dis_show_zero_x();      break;
   case _ind:     dis_show_ind();         break;
   case _ind_x:   dis_show_ind_x();       break;
   case _ind_y:   dis_show_ind_y();       break;
   }
}

void nes6502_disasm(uint32 PC, uint8 P, uint8 A, uint8 X, uint8 Y, uint8 S)
{
   pc_reg = PC;

   log_printf("%04X: ", pc_reg);

   switch(nes6502_getbyte(pc_reg))
   {
   case 0x00: dis_show_op("brk",_imp);    break;
   case 0x01: dis_show_op("ora",_ind_x);  break;
   case 0x02: dis_show_op("jam",_imp);    break;
   case 0x03: dis_show_op("slo",_ind_x);  break;
   case 0x04: dis_show_op("nop",_zero);   break;
   case 0x05: dis_show_op("ora",_zero);   break;
   case 0x06: dis_show_op("asl",_zero);   break;
   case 0x07: dis_show_op("slo",_zero);   break;
   case 0x08: dis_show_op("php",_imp);    break;
   case 0x09: dis_show_op("ora",_imm);    break;
   case 0x0a: dis_show_op("asl",_acc);    break;
   case 0x0b: dis_show_op("anc",_imm);    break;
   case 0x0c: dis_show_op("nop",_abs);    break;
   case 0x0d: dis_show_op("ora",_abs);    break;
   case 0x0e: dis_show_op("asl",_abs);    break;
   case 0x0f: dis_show_op("slo",_abs);    break;

   case 0x10: dis_show_op("bpl",_rel);    break;
   case 0x11: dis_show_op("ora",_ind_y);  break;
   case 0x12: dis_show_op("jam",_imp);    break;
   case 0x13: dis_show_op("slo",_ind_y);  break;
   case 0x14: dis_show_op("nop",_zero_x); break;
   case 0x15: dis_show_op("ora",_zero_x); break;
   case 0x16: dis_show_op("asl",_zero_x); break;
   case 0x17: dis_show_op("slo",_zero_x); break;
   case 0x18: dis_show_op("clc",_imp);    break;
   case 0x19: dis_show_op("ora",_abs_y);  break;
   case 0x1a: dis_show_op("nop",_imp);    break;
   case 0x1b: dis_show_op("slo",_abs_y);  break;
   case 0x1c: dis_show_op("nop",_abs_x);  break;
   case 0x1d: dis_show_op("ora",_abs_x);  break;
   case 0x1e: dis_show_op("asl",_abs_x);  break;
   case 0x1f: dis_show_op("slo",_abs_x);  break;

   case 0x20: dis_show_op("jsr",_abs);    break;
   case 0x21: dis_show_op("and",_ind_x);  break;
   case 0x22: dis_show_op("jam",_imp);    break;
   case 0x23: dis_show_op("rla",_ind_x);  break;
   case 0x24: dis_show_op("bit",_zero);   break;
   case 0x25: dis_show_op("and",_zero);   break;
   case 0x26: dis_show_op("rol",_zero);   break;
   case 0x27: dis_show_op("rla",_zero);   break;
   case 0x28: dis_show_op("plp",_imp);    break;
   case 0x29: dis_show_op("and",_imm);    break;
   case 0x2a: dis_show_op("rol",_acc);    break;
   case 0x2b: dis_show_op("anc",_imm);    break;
   case 0x2c: dis_show_op("bit",_abs);    break;
   case 0x2d: dis_show_op("and",_abs);    break;
   case 0x2e: dis_show_op("rol",_abs);    break;
   case 0x2f: dis_show_op("rla",_abs);    break;

   case 0x30: dis_show_op("bmi",_rel);    break;
   case 0x31: dis_show_op("and",_ind_y);  break;
   case 0x32: dis_show_op("jam",_imp);    break;
   case 0x33: dis_show_op("rla",_ind_y);  break;
/*   case 0x34: dis_show_op("nop",_zero);   break;*/
   case 0x34: dis_show_op("nop",_imp);    break;
   case 0x35: dis_show_op("and",_zero_x); break;
   case 0x36: dis_show_op("rol",_zero_x); break;
   case 0x37: dis_show_op("rla",_zero_x); break;
   case 0x38: dis_show_op("sec",_imp);    break;
   case 0x39: dis_show_op("and",_abs_y);  break;
   case 0x3a: dis_show_op("nop",_imp);    break;
   case 0x3b: dis_show_op("rla",_abs_y);  break;