1 files changed, 12 insertions, 3 deletions

diff --git a/ppu.h b/ppu.h
index ffd66d7..c5483e1 100644
--- a/ppu.h
+++ b/ppu.h
@@ -7,12 +7,23 @@
 #include "rom.h"
 
 struct ppu {
-        uint8_t oam[64*4];
         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 */
+                uint8_t x : 3;   /* fine x scroll */
+                uint8_t w : 1;   /* first/second write toggle */
+                uint8_t padding : 6;
+        } regs;
+
         struct ppu_ctrl {       /* $2000 */
                 uint8_t nmi_enable : 1;
                 uint8_t master_slave : 1;
@@ -36,8 +47,6 @@ struct ppu {
                 uint8_t sprite_overflow : 1;
                 uint8_t pad : 5;
         } status;
-        uint8_t oam_addr;       /* $2003 */
-        uint8_t oam_data;       /* $2004 */
 };
 extern struct ppu ppu;