M src/gba/gba-io.c → src/gba/gba-io.c

@@ -100,6 +100,7 @@ case REG_DMA2CNT_LO:
 	case REG_DMA3CNT_LO:
 		// Write-only register
 		return 0;
+	case REG_VCOUNT:
 	case REG_DMA0CNT_HI:
 	case REG_DMA1CNT_HI:
 	case REG_DMA2CNT_HI:

M src/gba/gba-video.c → src/gba/gba-video.c

@@ -1,6 +1,7 @@
 #include "gba-video.h"
 
 #include "gba.h"
+#include "gba-io.h"
 
 #include <limits.h>
 
@@ -55,6 +56,7 @@ video->inHblank = 0;
 			video->nextEvent = video->nextHblank;
 
 			++video->vcount;
+			video->p->memory.io[REG_VCOUNT >> 1] = video->vcount;
 
 			switch (video->vcount) {
 			case VIDEO_VERTICAL_PIXELS: