From 0b41e9e917bc77dcb994f943e99fe36f145573ee Mon Sep 17 00:00:00 2001
From: Gwilym Kuiper <gw@ilym.me>
Date: Sat, 5 Jun 2021 22:53:51 +0100
Subject: [PATCH] Sweep works backwards

---
 agb/src/sound/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/agb/src/sound/mod.rs b/agb/src/sound/mod.rs
index 525ef317..0bd8a9c3 100644
--- a/agb/src/sound/mod.rs
+++ b/agb/src/sound/mod.rs
@@ -129,7 +129,7 @@ impl SweepSettings {
 
     fn as_bits(&self) -> u16 {
         ((self.number_of_sweep_shifts as u16) & 0b111)
-            | (self.sound_direction.as_bits() << 3)
+            | ((1 - self.sound_direction.as_bits()) << 3) // sweep works backwards
             | ((self.sweep_time as u16) & 0b111) << 4
     }
 }