k6502.h

游戏模拟器InfoNes的原代码。有兴趣的可以将它移植到linux下

/*===================================================================*/
/*                                                                   */
/*  K6502.h : Header file for K6502                                  */
/*                                                                   */
/*  2000/05/29  InfoNES Project ( based on pNesX )                   */
/*                                                                   */
/*===================================================================*/

#ifndef K6502_H_INCLUDED
#define K6502_H_INCLUDED

/* Type definition  */
#ifndef DWORD
typedef unsigned long  DWORD;
#endif

#ifndef WORD
typedef unsigned short WORD;
#endif

#ifndef BYTE
typedef unsigned char  BYTE;
#endif

#ifndef NULL
#define NULL 0
#endif

/* 6502 Flags */
#define FLAG_C 0x01
#define FLAG_Z 0x02
#define FLAG_B 0x10          //遇到指令BRK时，该位被置位
#define FLAG_I 0x04
#define FLAG_D 0x08
#define FLAG_R 0x20
#define FLAG_V 0x40
#define FLAG_N 0x80

/* Stack Address */
#define BASE_STACK   0x100   //堆栈地址从0x0100到0x01ff,栈底是0x01ff,
                             //但由于系统占用了一些堆栈，实际上堆栈指针刚开始是指向0x01b4的而不是0x01ff

/* Interrupt Vectors */
#define VECTOR_NMI   0xfffa
#define VECTOR_RESET 0xfffc
#define VECTOR_IRQ   0xfffe

/* NMI Request  */
#define NMI_REQ  NMI_State = 0;

/* IRQ Request  */
#define IRQ_REQ  IRQ_State = 0;

/* Emulator Operation  */
void K6502_Init();
void K6502_Reset();
void K6502_Set_Int_Wiring( BYTE byNMI_Wiring, BYTE byIRQ_Wiring );
void K6502_Step( register WORD wClocks );

/* I/O Operation (User definition)  */
static  BYTE K6502_Read( WORD wAddr );
static  WORD K6502_ReadW2( WORD wAddr );
#if 1
static  WORD K6502_ReadZpW( BYTE byAddr );
#endif
static  BYTE K6502_ReadAbsX();
static  BYTE K6502_ReadAbsY();
static  BYTE K6502_ReadIY();
static  BYTE K6502_Read_Code( WORD wAddr );
static  WORD K6502_ReadW_Code( WORD wAddr );
static  void K6502_Write( WORD wAddr, BYTE byData );

/* The state of the IRQ pin  */
extern BYTE IRQ_State;

/* The state of the NMI pin  */
extern BYTE NMI_State;

/* The number of the clocks that it passed  */
extern WORD g_wPassedClocks;

#define	K6502_ReadZp(byAddr) (RAM[ byAddr ])
#if 0
#define K6502_ReadZpW(wAddr)	((WORD)RAM[wAddr & 0x7ff ])
#endif
#define	K6502_WriteZp(byAddr,byData) (RAM[ byAddr ] = byData)
	
#define	K6502_ReadW(wAddr)	(*(WORD *)&RAM[wAddr & 0x7ff ])

#define K6502_WriteW(wAddr, wData)	((WORD)RAM[wAddr & 0x7ff] = wData)

#endif /* !K6502_H_INCLUDED */