nesemu/cpu/cpu.h

//
// Created by william on 10/15/23.
//

#ifndef CPU_CPU_H
#define CPU_CPU_H

#include <stdbool.h>
#include "memory.h"

// Reference: https://www.nesdev.org/wiki/Status_flags
#define CPU_STATUS_CARRY_MASK 0x01
#define CPU_STATUS_ZERO_MASK 0x02
#define CPU_STATUS_INTERRUPT_DISABLE_MASK 0x04
#define CPU_STATUS_DECIMAL_MASK 0x08
#define CPU_STATUS_B_MASK 0x10
#define CPU_STATUS_I_MASK 0x20
#define CPU_STATUS_OVERFLOW_MASK 0x40
#define CPU_STATUS_NEGATIVE_MASK 0x80

#define CPU_STACK_ADDR 0x0100

// Reference: https://www.nesdev.org/obelisk-6502-guide/registers.html
typedef struct {
    address program_counter;
    byte stack_pointer;
    byte accumulator;
    byte x;
    byte y;
    byte status;
} CpuRegisters;

enum OperandType {
    OPERAND_TYPE_ACCUMULATOR,
    OPERAND_TYPE_IMMEDIATE,
    OPERAND_TYPE_ADDRESS
};

typedef struct {
    word value;
    enum OperandType type;
    bool is_page_crossing;
} Operand;

char* operand_name(Operand *operand);

CpuRegisters* cpu_get_registers();
byte cpu_get_flag(byte mask);
void cpu_set_flag(bool set, byte mask);

byte cpu_get_next_byte();
word cpu_get_next_word();

byte cpu_peek_byte(address addr);
word cpu_peek_word(address addr);
void cpu_push_byte(byte value, address addr);

void cpu_stack_push(byte value);
void cpu_stack_push_context();
byte cpu_stack_pop();
void cpu_stack_pop_context();

void cpu_add_cycles(unsigned int cycle_count);

#endif //CPU_CPU_H