From 7a7d16b4f7b717e639182ae21a7bcb3c6e474ac6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Sun, 6 Aug 2023 23:54:37 +0100
Subject: [PATCH] fix: issue with the DMA transfer on DMG
---
src/mmu.rs | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/src/mmu.rs b/src/mmu.rs
index a2f92b7a..9b02f33f 100644
--- a/src/mmu.rs
+++ b/src/mmu.rs
@@ -244,8 +244,14 @@ impl Mmu {
}
// @TODO: Implement DMA transfer in a better way
- let data = self.read_many(self.dma.source(), self.dma.length());
- self.write_many(self.dma.destination(), &data);
+
+ // only runs the DMA transfer if the system is in CGB mode
+ // this avoid issues when writing to DMG unmapped registers
+ // that would otherwise cause the system to crash
+ if self.mode == GameBoyMode::Cgb {
+ let data = self.read_many(self.dma.source(), self.dma.length());
+ self.write_many(self.dma.destination(), &data);
+ }
self.dma.set_active(false);
}
--
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