From d8578f1f581f666f8b120dfb33e666262e5816cd Mon Sep 17 00:00:00 2001
From: luigi__ <luigi__@users.sf.net>
Date: Thu, 8 Oct 2009 19:58:15 +0000
Subject: [PATCH] Re-implement BIOS SoundBias function more correctly. Get rid
 of SPU_ReadLong. (is the bias feature really used by many games anyway? I
 don't think so)

---
 desmume/src/SPU.cpp  |  9 ---------
 desmume/src/SPU.h    |  1 -
 desmume/src/bios.cpp | 12 ++++++------
 3 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/desmume/src/SPU.cpp b/desmume/src/SPU.cpp
index 5c934bca6..4f0850097 100644
--- a/desmume/src/SPU.cpp
+++ b/desmume/src/SPU.cpp
@@ -515,15 +515,6 @@ void SPU_struct::KeyOn(int channel)
 
 //////////////////////////////////////////////////////////////////////////////
 
-u32 SPU_ReadLong(u32 addr)
-{
-	addr &= 0xFFF;
-
-	return T1ReadLong(MMU.ARM7_REG, addr);
-}
-
-//////////////////////////////////////////////////////////////////////////////
-
 void SPU_struct::WriteByte(u32 addr, u8 val)
 {
 	channel_struct &thischan=channels[(addr >> 4) & 0xF];
diff --git a/desmume/src/SPU.h b/desmume/src/SPU.h
index 0adb14520..21d8f38e8 100644
--- a/desmume/src/SPU.h
+++ b/desmume/src/SPU.h
@@ -139,7 +139,6 @@ void SPU_KeyOn(int channel);
 void SPU_WriteByte(u32 addr, u8 val);
 void SPU_WriteWord(u32 addr, u16 val);
 void SPU_WriteLong(u32 addr, u32 val);
-u32 SPU_ReadLong(u32 addr);
 void SPU_Emulate_core(void);
 void SPU_Emulate_user(void);
 
diff --git a/desmume/src/bios.cpp b/desmume/src/bios.cpp
index 5852f3746..951b6281c 100644
--- a/desmume/src/bios.cpp
+++ b/desmume/src/bios.cpp
@@ -1049,12 +1049,12 @@ TEMPLATE static u32 isDebugger()
 
 TEMPLATE static u32 SoundBias()
 {
-     u32 current = SPU_ReadLong(0x4000504);
-     if (cpu->R[0] > current)
-	SPU_WriteLong(0x4000504, current + 0x1);
-     else
-	SPU_WriteLong(0x4000504, current - 0x1);
-     return cpu->R[1];
+     u32 curBias = _MMU_read32<ARMCPU_ARM7>(0x04000504);
+	 u32 newBias = (curBias == 0) ? 0x000:0x200;
+	 u32 delay = (newBias > curBias) ? (newBias-curBias) : (curBias-newBias);
+
+	 _MMU_write32<ARMCPU_ARM7>(0x04000504, newBias);
+     return cpu->R[1] * delay;
 }
 
 TEMPLATE static u32 getBootProcs()