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#ifndef GB_H
#define GB_H
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
#include <stdint.h>
typedef enum {
GB_CPU_STATE_RUN,
GB_CPU_STATE_STOP,
GB_CPU_STATE_HALT,
GB_CPU_STATE_INVALID,
GB_CPU_STATE_NOT_IMPLEMENTED,
GB_CPU_STATE_LAST,
} gb_cpu_state_t;
#define GB_BTN_UP 1
#define GB_BTN_DOWN (1 << 1)
#define GB_BTN_LEFT (1 << 2)
#define GB_BTN_RIGHT (1 << 3)
#define GB_BTN_A (1 << 4)
#define GB_BTN_B (1 << 5)
#define GB_BTN_SELECT (1 << 6)
#define GB_BTN_START (1 << 7)
// frame size, in bytes
#define GB_FRAME_SIZE (3 * 160 * 144)
typedef struct {
struct {
// _Bool in_bios;
// FIXME: combine these?
uint8_t ram[0x2000]; // working ram (8k)
uint8_t eram[65536]; // external ram (banked, up to 64k)
uint8_t vram[0x2000]; // vram (8k)
uint8_t oam[0xA0]; // oam (160 bytes)
uint8_t zram[0x7F]; // zram (128 bytes)
// rom (at least 32k)
const uint8_t *rom;
uint32_t rom_size;
union {
struct {
// current rom bank (5 bits); see note about
// rom_ram_mode below
uint8_t rom_bank;
// is external ram enabled?
_Bool ram_enable;
// ram bank
// rom_ram_mode == 0: high two bits of rom bank
// rom_ram_mode == 1: ram bank
uint8_t ram_bank;
// set interpretation of ram_bank
_Bool rom_ram_mode;
} mbc1;
struct {
// current rom bank (4 bits)
uint8_t rom_bank;
// is eram enabled?
_Bool ram_enable;
} mbc2;
};
// interrupts
// ie: interrupt enable (addr: 0xFFFF)
// iv: interrupt vector (addr: 0xFF0F)
// (gb-manual, p26)
uint8_t ie;
uint8_t iv;
// buttons (addr: 0xFF00)
// gb-manual, p23
uint8_t p1_mode;
uint8_t btns;
} mmu;
struct {
uint16_t clock;
uint8_t mode,
lcdc,
stat,
scy,
scx,
wy,
wx,
bgp,
obp0,
obp1,
line,
lyc;
uint8_t rgb[GB_FRAME_SIZE];
uint32_t frame;
} gpu;
struct {
uint16_t div;
uint32_t tima; // NOTE: cannot be uint16_t because of 10-bit shift
uint8_t tma,
tac;
} timer;
struct {
uint16_t rs[6 /* RW_LAST */];
uint32_t clock; /* FIXME: uint16_t? */
gb_cpu_state_t state;
// interrupt master enable
_Bool ime;
} cpu;
} gb_t;
void gb_init(gb_t * const, const uint8_t *rom, const uint32_t rom_size);
void gb_set_buttons(gb_t * const, const uint8_t);
void gb_frame(gb_t * const);
void gb_step(gb_t * const);
const uint8_t *gb_get_rgb_frame(const gb_t * const);
#ifdef __cplusplus
};
#endif /* __cplusplus */
#endif /* GB_H */
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