From fa184730af2f2be094aa9f37cd3abf58d10f79ea Mon Sep 17 00:00:00 2001
From: Bertrand Augereau
Date: Sun, 22 Jun 2003 11:52:40 +0000
Subject: Reduced the number of shifts in highly used functions in Super2xSaI
 and SuperEagle

svn-id: r8604
---
 common/scaler.cpp | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

(limited to 'common/scaler.cpp')

diff --git a/common/scaler.cpp b/common/scaler.cpp
index c10bcccfab..1607fef214 100644
--- a/common/scaler.cpp
+++ b/common/scaler.cpp
@@ -90,17 +90,19 @@ static inline int GetResult(uint32 A, uint32 B, uint32 C, uint32 D) {
 }
 
 static inline uint32 INTERPOLATE(uint32 A, uint32 B) {
-	if (A != B) {
-		return (((A & colorMask) >> 1) + ((B & colorMask) >> 1) + (A & B & lowPixelMask));
+	if (A != B) {	
+		// Non regression test
+		assert ((((A & colorMask) + (B & colorMask)) >> 1) + (A & B & lowPixelMask)==(((A & colorMask) >> 1) + ((B & colorMask) >> 1) + (A & B & lowPixelMask)));
+		return (((A & colorMask) + (B & colorMask)) >> 1) + (A & B & lowPixelMask);
 	} else
 		return A;
 }
 
 static inline uint32 Q_INTERPOLATE(uint32 A, uint32 B, uint32 C, uint32 D) {
-	register uint32 x = ((A & qcolorMask) >> 2) +
-		((B & qcolorMask) >> 2) + ((C & qcolorMask) >> 2) + ((D & qcolorMask) >> 2);
-	register uint32 y = (A & qlowpixelMask) +
-		(B & qlowpixelMask) + (C & qlowpixelMask) + (D & qlowpixelMask);
+	register uint32 x = ((A & qcolorMask) + (B & qcolorMask) + (C & qcolorMask) + (D & qcolorMask))>>2;
+	// Non regression test
+	assert (x==((A & qcolorMask) >> 2) + ((B & qcolorMask) >> 2) + ((C & qcolorMask) >> 2) + ((D & qcolorMask) >> 2));
+	register uint32 y = (A & qlowpixelMask) + (B & qlowpixelMask) + (C & qlowpixelMask) + (D & qlowpixelMask);
 
 	y = (y >> 2) & qlowpixelMask;
 	return x + y;
-- 
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