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