through sub_8009414

include/gba/io_reg.h

@@ -584,6 +584,23 @@
 #define TIMER_INTR_ENABLE 0x40
 #define TIMER_ENABLE      0x80
 
+// BGCNT
+#define BGCNT_PRIORITY(n)          (n) // Values 0 - 3. Lower priority BGs will be drawn on top of higher priority BGs.
+#define BGCNT_CHARBASE(n)   ((n) << 2) // Values 0 - 3. Base block for tile pixel data.
+#define BGCNT_MOSAIC            0x0040
+#define BGCNT_16COLOR           0x0000 // 4 bits per pixel
+#define BGCNT_256COLOR          0x0080 // 8 bits per pixel
+#define BGCNT_SCREENBASE(n) ((n) << 8) // Values 0 - 31. Base block for tile map.
+#define BGCNT_WRAP              0x2000 // Only affects affine BGs. Text BGs wrap by default.
+#define BGCNT_TXT256x256        0x0000 // Internal screen size size of text mode BG in pixels.
+#define BGCNT_TXT512x256        0x4000
+#define BGCNT_TXT256x512        0x8000
+#define BGCNT_TXT512x512        0xC000
+#define BGCNT_AFF128x128        0x0000 // Internal screen size size of affine mode BG in pixels.
+#define BGCNT_AFF256x256        0x4000
+#define BGCNT_AFF512x512        0x8000
+#define BGCNT_AFF1024x1024      0xC000
+
 // serial
 #define SIO_ID             0x0030 // Communication ID