GBA Video: Start timing mid-scanline when skipping BIOS

mgba-emu · May 27, 2018 · 2aa8716 · 2aa8716
1 parent 38228e9
commit 2aa8716
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Showing 2 changed files with 5 additions and 2 deletions.
diff --git a/CHANGES b/CHANGES
@@ -33,6 +33,7 @@ Bugfixes:
  - GBA Hardware: Fix RTC overriding light sensor (fixes mgba.io/i/1069)
  - GBA Savedata: Fix savedata modified time updating when read-only
  - GB Video: Fix enabling window when LY > WY (fixes mgba.io/i/409)
+ - GBA Video: Start timing mid-scanline when skipping BIOS
 Misc:
  - GBA Timer: Use global cycles for timers
  - GBA: Extend oddly-sized ROMs to full address space (fixes mgba.io/i/722)

diff --git a/src/gba/video.c b/src/gba/video.c
@@ -78,16 +78,18 @@ void GBAVideoInit(struct GBAVideo* video) {
 }
 
 void GBAVideoReset(struct GBAVideo* video) {
+	int32_t nextEvent = VIDEO_HDRAW_LENGTH;
 	if (video->p->memory.fullBios) {
 		video->vcount = 0;
 	} else {
-		// TODO: Verify exact scanline hardware
+		// TODO: Verify exact scanline on hardware
 		video->vcount = 0x7E;
+		nextEvent = 170;
 	}
 	video->p->memory.io[REG_VCOUNT >> 1] = video->vcount;
 
 	video->event.callback = _startHblank;
-	mTimingSchedule(&video->p->timing, &video->event, VIDEO_HDRAW_LENGTH);
+	mTimingSchedule(&video->p->timing, &video->event, nextEvent);
 
 	video->frameCounter = 0;
 	video->frameskipCounter = 0;