[OMPT-svn-commit] SF.net SVN: modplug:[2313] trunk/OpenMPT/soundlib

[<man...@us...>]

Revision: 2313
          http://sourceforge.net/p/modplug/code/2313
Author:   manxorist
Date:     2013-06-07 18:08:18 +0000 (Fri, 07 Jun 2013)
Log Message:
-----------
[Ref] Add 1:1 bit-exact C translation of X86_Dither().

Modified Paths:
--------------
    trunk/OpenMPT/soundlib/Fastmix.cpp
    trunk/OpenMPT/soundlib/Sndmix.cpp
    trunk/OpenMPT/soundlib/Waveform.cpp

Modified: trunk/OpenMPT/soundlib/Fastmix.cpp
===================================================================
--- trunk/OpenMPT/soundlib/Fastmix.cpp	2013-06-07 00:24:30 UTC (rev 2312)
+++ trunk/OpenMPT/soundlib/Fastmix.cpp	2013-06-07 18:08:18 UTC (rev 2313)
@@ -2089,6 +2089,7 @@
 
 
 #ifdef ENABLE_X86
+
 void X86_Dither(int *pBuffer, UINT nSamples, UINT nBits)
 //------------------------------------------------------
 {
@@ -2116,18 +2117,6 @@
 	mov edx, ebx
 	sar edx, cl
 	add eax, edx
-/*
-	int a = 0, b = 0;
-	for (UINT i=0; i<len; i++)
-	{
-		a = (a << 1) | (((DWORD)a) >> (BYTE)31);
-		a ^= 0x10204080;
-		a += 0x78649E7D + (b << 2);
-		b += ((a << 16) | (a >> 16)) * 5;
-		int c = a + b;
-		p[i] = ((signed char)c ) >> 1;
-	}
-*/
 	dec ebp
 	mov dword ptr [esi-4], eax
 	jnz noiseloop
@@ -2136,9 +2125,52 @@
 	mov gDitherB, ebx
 	}
 }
-#endif
 
+#endif // ENABLE_X86
 
+
+static forceinline int32 dither_rand(uint32 &a, uint32 &b)
+//--------------------------------------------------------
+{
+	a = (a << 1) | (a >> 31);
+	a ^= 0x10204080u;
+	a += 0x78649E7Du + (b * 4);
+	b += ((a << 16 ) | (a >> 16)) * 5;
+	return (int32)b;
+}
+
+static void C_Dither(int *pBuffer, UINT nSamples, UINT nBits)
+//-----------------------------------------------------------
+{
+
+	static uint32 global_a = 0;
+	static uint32 global_b = 0;
+
+	uint32 a = global_a;
+	uint32 b = global_b;
+
+	while(nSamples--)
+	{
+		*pBuffer += dither_rand(a, b) >> (nBits + MIXING_ATTENUATION + 1);
+		pBuffer++;
+	}
+
+	global_a = a;
+	global_b = b;
+
+}
+
+void Dither(int *pBuffer, UINT nSamples, UINT nBits)
+//--------------------------------------------------
+{
+	#if defined(ENABLE_X86)
+		X86_Dither(pBuffer, nSamples, nBits);
+	#else
+		C_Dither(pBuffer, nSamples, nBits);
+	#endif
+}
+
+
 #ifdef ENABLE_X86
 static void X86_InterleaveFrontRear(int *pFrontBuf, int *pRearBuf, DWORD nFrames)
 //-------------------------------------------------------------------------------

Modified: trunk/OpenMPT/soundlib/Sndmix.cpp
===================================================================
--- trunk/OpenMPT/soundlib/Sndmix.cpp	2013-06-07 00:24:30 UTC (rev 2312)
+++ trunk/OpenMPT/soundlib/Sndmix.cpp	2013-06-07 18:08:18 UTC (rev 2313)
@@ -62,9 +62,7 @@
 
 
 
-#ifdef ENABLE_X86
-extern VOID X86_Dither(int *pBuffer, UINT nSamples, UINT nBits);
-#endif
+extern void Dither(int *pBuffer, UINT nSamples, UINT nBits);
 extern void InterleaveFrontRear(int *pFrontBuf, int *pRearBuf, DWORD nFrames);
 extern void StereoFill(int *pBuffer, UINT nSamples, LPLONG lpROfs, LPLONG lpLOfs);
 extern void MonoFromStereo(int *pMixBuf, UINT nSamples);
@@ -364,14 +362,12 @@
 			lTotalSampleCount *= 2;
 		}
 
-#ifdef ENABLE_X86
 		// Noise Shaping
 		if (m_MixerSettings.GetBitsPerSample() <= 16)
 		{
 			if(m_Resampler.IsHQ())
-				X86_Dither(MixSoundBuffer, lTotalSampleCount, m_MixerSettings.GetBitsPerSample());
+				Dither(MixSoundBuffer, lTotalSampleCount, m_MixerSettings.GetBitsPerSample());
 		}
-#endif
 
 #ifdef MODPLUG_TRACKER
 		// Hook Function

Modified: trunk/OpenMPT/soundlib/Waveform.cpp
===================================================================
--- trunk/OpenMPT/soundlib/Waveform.cpp	2013-06-07 00:24:30 UTC (rev 2312)
+++ trunk/OpenMPT/soundlib/Waveform.cpp	2013-06-07 18:08:18 UTC (rev 2313)
@@ -53,9 +53,7 @@
 
 #endif
 
-#ifdef ENABLE_X86
-extern void X86_Dither(int *pBuffer, UINT nSamples, UINT nBits);
-#endif
+extern void Dither(int *pBuffer, UINT nSamples, UINT nBits);
 extern DWORD Convert32To8(LPVOID lpBuffer, int *, DWORD nSamples);
 extern DWORD Convert32To16(LPVOID lpBuffer, int *, DWORD nSamples);
 extern DWORD Convert32To24(LPVOID lpBuffer, int *, DWORD nSamples);
@@ -70,7 +68,7 @@
 	{
 		int nbuf = (n > MIXBUFFERSIZE * 2) ? MIXBUFFERSIZE * 2 : n;
 		X86_Normalize24BitBuffer(pbuffer, nbuf, lmax24, tempbuf);
-		X86_Dither(tempbuf, nbuf, 8 * dwByteInc);
+		Dither(tempbuf, nbuf, 8 * dwByteInc);
 		switch(dwByteInc)
 		{
 		case 2:		Convert32To16(pbuffer, tempbuf, nbuf); break;

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