GBA BIOS: Fix reloading video registers after reset (fixes mgba-emu#1808

)
TASEmulators · Aug 29, 2020 · ae1fe1e · ae1fe1e
1 parent 2bb6b7d
commit ae1fe1e
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diff --git a/CHANGES b/CHANGES
@@ -14,6 +14,7 @@ Emulation fixes:
  - GBA: Fix timing advancing too quickly in rare cases
  - GBA BIOS: Implement dummy sound driver calls
  - GBA BIOS: Improve HLE BIOS timing
+ - GBA BIOS: Fix reloading video registers after reset (fixes mgba.io/i/1808)
  - GBA DMA: Linger last DMA on bus (fixes mgba.io/i/301 and mgba.io/i/1320)
  - GBA Memory: Improve gamepak prefetch timing
  - GBA SIO: Fix copying Normal mode transfer values

diff --git a/src/gba/bios.c b/src/gba/bios.c
@@ -179,6 +179,11 @@ static void _RegisterRamReset(struct GBA* gba) {
 	}
 	if (registers & 0x9C) {
 		gba->video.renderer->reset(gba->video.renderer);
+		gba->video.renderer->writeVideoRegister(gba->video.renderer, REG_DISPCNT, gba->memory.io[REG_DISPCNT >> 1]);
+		int i;
+		for (i = REG_BG0CNT; i < REG_SOUND1CNT_LO; i += 2) {
+			gba->video.renderer->writeVideoRegister(gba->video.renderer, i, gba->memory.io[i >> 1]);
+		}
 	}
 }