Unrolled most inner loop of ColorRasterizer::MergePlaneBuffersToCurrentLine to gain a total speed up of about 5 percent.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@11440 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/print/drivers/pcl6/PCL6Rasterizer.cpp

@@ -182,30 +182,75 @@ ColorRasterizer::MergePlaneBuffersToCurrentLine()
 	
 	// iterate over the three plane buffers
 	for (int i = 0; i < fPlaneBufferSize; i ++) {
-		const uchar values[3] = { 
-			fPlaneBuffers[0][i],
-			fPlaneBuffers[1][i],
-			fPlaneBuffers[2][i]
-		};
-		
 		int pixels = 8;
 		if (remainingPixels < 8) {
 			pixels = remainingPixels;
 		}
 		remainingPixels -= pixels;
 
+		if (remainingPixels >= 8) {
+			register const uchar
+				red   = fPlaneBuffers[0][i],
+				green = fPlaneBuffers[1][i],
+				blue  = fPlaneBuffers[2][i];
+
+			register uchar value = 0;
+			if (red   & 0x80) value =  0x80;
+			if (red   & 0x40) value |=  0x10;
+			if (red   & 0x20) value |=  0x02;
+
+			if (green & 0x80) value |= 0x40;
+			if (green & 0x40) value |= 0x08;
+			if (green & 0x20) value |= 0x01;			
+
+			if (blue  & 0x80) value |= 0x20;
+			if (blue  & 0x40) value |= 0x04;
+
+			*out++ = value;
+			
+			value = 0;
+			if (blue  & 0x20) value =  0x80;
+			if (blue  & 0x10) value |=  0x10;
+			if (blue  & 0x08) value |=  0x02;
+
+			if (red   & 0x10) value |= 0x40;
+			if (red   & 0x08) value |= 0x08;
+			if (red   & 0x04) value |= 0x01;
+
+			if (green & 0x10) value |= 0x20;
+			if (green & 0x08) value |= 0x04;
+			*out++ = value;
+			
+			value = 0;
+			if (green & 0x04) value =  0x80;
+			if (green & 0x02) value |=  0x10;
+			if (green & 0x01) value |=  0x02;
+
+			if (blue  & 0x04) value |= 0x40;
+			if (blue  & 0x02) value |= 0x08;
+			if (blue  & 0x01) value |= 0x01;
+
+			if (red   & 0x02) value |= 0x20;
+			if (red   & 0x01) value |= 0x04;
+			*out++ = value;
+	
+		} else {
+			register const uchar
+				red   = fPlaneBuffers[0][i],
+				green = fPlaneBuffers[1][i],
+				blue  = fPlaneBuffers[2][i];
 			// for each bit in the current byte of each plane	
 			uchar mask = 0x80;
 			for (; pixels > 0; pixels --) {			
 				int rgb = 0;
 				
-			if (values[0] & mask) {
+				if (red & mask) {
 					rgb |= kRed;
 				}
-			if (values[1] & mask) {
+				if (green & mask) {
 					rgb |= kGreen;
 				}
-			if (values[2] & mask) {
+				if (blue & mask) {
 					rgb |= kBlue;
 				}
 				
@@ -229,6 +274,7 @@ ColorRasterizer::MergePlaneBuffersToCurrentLine()
 				mask >>= 1;
 			}	
 		}
+	}
 	
 	// write last output value
 	if (outMask != 0x80) {
@@ -358,7 +404,6 @@ static void initializeBitmap(BBitmap *bitmap, int width, int height)
 	}
 }
 
-#if 1
 int main() 
 {
 	const int width = 10;
@@ -379,10 +424,8 @@ int main()
 	rasterizer.SetBitmap(0, 0, &bitmap, height);
 	rasterizer.InitializeBuffer();
 	while (rasterizer.HasNextLine()) {
-		// const uchar *rowBuffer = (uchar*) 
 		rasterizer.RasterizeNextLine();
 	}
 }
-#endif
 
 #endif