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cc65/include/6502.h
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89 lines
2.2 KiB
C

/*
* 6502.h
*
* Ullrich von Bassewitz, 20.09.1998
*/
#ifndef _6502_H
#define _6502_H
/* Possible returns of getcpu() */
#define CPU_6502 0
#define CPU_65C02 1
#define CPU_65816 2
unsigned char getcpu (void);
/* Detect the CPU the program is running on */
/* Macros for CPU instructions */
#define BRK() __asm__ ("\tbrk")
#define CLI() __asm__ ("\tcli")
#define SEI() __asm__ ("\tsei")
#define JAM() __asm__ ("\t.byte\t$02")
/* Struct that holds the registers for the sys function */
struct regs {
unsigned char a; /* A register value */
unsigned char x; /* X register value */
unsigned char y; /* Y register value */
unsigned char flags; /* Flags value */
unsigned pc; /* Program counter */
};
/* Defines for the flags in the regs structure */
#define F_NEG 0x80 /* N flag */
#define F_OVF 0x40 /* V flag */
#define F_BRK 0x10 /* B flag */
#define F_DEC 0x08 /* D flag */
#define F_IEN 0x04 /* I flag */
#define F_ZERO 0x02 /* Z flag */
#define F_CARRY 0x01 /* C flag */
/* Function to call any machine language subroutine. All registers in the
* regs structure are passed into the routine and the results are passed
* out. Some of the flags are ignored on input. The called routine must
* end with an RTS.
*/
void __fastcall__ _sys (struct regs* r);
/* Set and reset the break vector. The given user function is called if
* a break occurs. The values of the registers may be read from the brk_...
* variables. The value in brk_pc will point to the address that contains
* the brk instruction.
* The set_brk function will install an exit handler that will reset the
* vector if the program ends.
*/
extern unsigned char brk_a; /* A register value */
extern unsigned char brk_x; /* X register value */
extern unsigned char brk_y; /* Y register value */
extern unsigned char brk_sr; /* Status register */
extern unsigned brk_pc; /* PC value */
typedef void (*brk_handler) (void);
/* Type of the break handler */
void __fastcall__ set_brk (brk_handler f);
/* Set the break vector to the given address, return the old address */
void reset_brk (void);
/* Reset the break vector to the original value */
/* End of 6502.h */
#endif