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#ifndef PPU_H
#define PPU_H
#include <stdio.h>
#include <stdint.h>
#include "rom.h"
struct ppu {
uint8_t vram[2048];
uint8_t oam[64*4];
uint8_t oam_addr; /* $2003 */
uint8_t palette[16*2];
uint16_t cycles, scanlines;
struct rom *rom;
uint8_t last_read;
struct ppu_regs {
uint16_t v : 15; /* current vram address */
uint16_t t : 15; /* temporary vram address */
uint16_t scroll_x : 9; /* x scroll position */
uint16_t scroll_y : 9; /* y scroll position */
uint8_t write_toggle : 1; /* first/second write toggle */
} regs;
struct ppu_ctrl { /* $2000 */
uint8_t nmi_enable : 1;
uint8_t master_slave : 1;
uint8_t sprite_height : 1;
uint8_t bg_tile_sel : 1;
uint8_t sprite_tile_sel : 1;
uint8_t inc_mode : 1;
uint8_t nametable_base : 2;
} ctrl;
struct ppu_mask { /* $2001 */
uint8_t colour_emphasis : 3;
uint8_t sprite_enable : 1;
uint8_t bg_enable : 1;
uint8_t sprite_left_enable : 1;
uint8_t bg_left_enable : 1;
uint8_t grayscale : 1;
} mask;
struct ppu_status { /* $2002 */
uint8_t vblank : 1;
uint8_t sprite0_hit : 1;
uint8_t sprite_overflow : 1;
uint8_t pad : 5;
} status;
};
extern struct ppu ppu;
void ppu_tick(void);
#endif /* PPU_H */
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