M CHANGES → CHANGES

@@ -6,6 +6,7 @@ Emulation fixes:
  - ARM: Fix ALU reading PC after shifting
  - ARM: Fix STR storing PC after address calculation
  - GB: Fix GBC game registers after skipping BIOS
+ - GB Video: Fix state after skipping BIOS (fixes mgba.io/i/1715 and mgba.io/i/1716)
  - GBA: Add missing RTC overrides for Legendz games
  - GBA BIOS: Implement dummy sound driver calls
  - GBA BIOS: Improve HLE BIOS timing

M include/mgba/internal/gb/video.h → include/mgba/internal/gb/video.h

@@ -161,6 +161,7 @@ void GBVideoInit(struct GBVideo* video);
 void GBVideoReset(struct GBVideo* video);
 void GBVideoDeinit(struct GBVideo* video);
 void GBVideoAssociateRenderer(struct GBVideo* video, struct GBVideoRenderer* renderer);
+void GBVideoSkipBIOS(struct GBVideo* video);
 void GBVideoProcessDots(struct GBVideo* video, uint32_t cyclesLate);
 
 void GBVideoWriteLCDC(struct GBVideo* video, GBRegisterLCDC value);

M src/gb/gb.c → src/gb/gb.c

@@ -460,13 +460,13 @@ }
 
 	GBVideoReset(&gb->video);
 	GBTimerReset(&gb->timer);
+	GBIOReset(gb);
 	if (!gb->biosVf) {
 		GBSkipBIOS(gb);
 	} else {
 		mTimingSchedule(&gb->timing, &gb->timer.event, 0);
 	}
 
-	GBIOReset(gb);
 	GBAudioReset(&gb->audio);
 	GBSIOReset(&gb->sio);
 
@@ -561,6 +561,7 @@ mTimingDeschedule(&gb->timing, &gb->timer.event);
 	mTimingSchedule(&gb->timing, &gb->timer.event, 0);
 
 	GBIOWrite(gb, REG_LCDC, 0x91);
+	GBVideoSkipBIOS(&gb->video);
 
 	if (gb->biosVf) {
 		GBUnmapBIOS(gb);

M src/gb/video.c → src/gb/video.c

@@ -214,6 +214,24 @@ }
 	return false;
 }
 
+void GBVideoSkipBIOS(struct GBVideo* video) {
+	video->mode = 1;
+	video->modeEvent.callback = _endMode1;
+
+	if (video->p->model == GB_MODEL_CGB) {
+		video->ly = GB_VIDEO_VERTICAL_PIXELS;
+		video->p->memory.io[REG_LY] = video->ly;
+		video->stat = GBRegisterSTATClearLYC(video->stat);
+	}
+	video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
+
+	video->p->memory.io[REG_IF] |= (1 << GB_IRQ_VBLANK);
+	GBUpdateIRQs(video->p);
+	video->p->memory.io[REG_STAT] = video->stat;
+	mTimingDeschedule(&video->p->timing, &video->modeEvent);
+	mTimingSchedule(&video->p->timing, &video->modeEvent, GB_VIDEO_HORIZONTAL_LENGTH << video->p->doubleSpeed);
+}
+
 void _endMode0(struct mTiming* timing, void* context, uint32_t cyclesLate) {
 	struct GBVideo* video = context;
 	if (video->frameskipCounter <= 0) {