start working on ppu

1 files changed, 26 insertions, 0 deletions

diff --git a/ppu.h b/ppu.h
index 6bc8b5a..ffd66d7 100644
--- a/ppu.h
+++ b/ppu.h
@@ -12,6 +12,32 @@ struct ppu {
         uint8_t palette[16*2];
         uint16_t cycles, scanlines;
         struct rom *rom;
+
+        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_sel : 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;
+        uint8_t oam_addr;       /* $2003 */
+        uint8_t oam_data;       /* $2004 */
 };
 extern struct ppu ppu;