Mesa (master): radeon: Remove the loop from stride size calculation.

[Pauli Nieminen]

Module: Mesa
Branch: master
Commit: 9d5f88250379666961f92a7e20cf0d48907c38e2
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=9d5f88250379666961f92a7e20cf0d48907c38e2

Author: Pauli Nieminen <suokkos at gmail.com>
Date:   Sat Feb  6 03:01:57 2010 +0200

radeon: Remove the loop from stride size calculation.

Changed stride size calculation to do the math by rounding
the value instead of loop. r600 minimum stride is 256 which
might might cause up to about 60 rounds of the loop.

---

 src/mesa/drivers/dri/radeon/radeon_mipmap_tree.c |   22 ++++++++++++++--------
 1 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/mesa/drivers/dri/radeon/radeon_mipmap_tree.c b/src/mesa/drivers/dri/radeon/radeon_mipmap_tree.c
index 90a4e4f..836b042 100644
--- a/src/mesa/drivers/dri/radeon/radeon_mipmap_tree.c
+++ b/src/mesa/drivers/dri/radeon/radeon_mipmap_tree.c
@@ -41,18 +41,24 @@ static unsigned get_aligned_compressed_row_stride(
 		unsigned width,
 		unsigned minStride)
 {
-	const unsigned blockSize = _mesa_get_format_bytes(format);
-	unsigned blockWidth, blockHeight, numXBlocks;
+	const unsigned blockBytes = _mesa_get_format_bytes(format);
+	unsigned blockWidth, blockHeight;
+	unsigned stride;
 
 	_mesa_get_format_block_size(format, &blockWidth, &blockHeight);
-	numXBlocks = (width + blockWidth - 1) / blockWidth;
 
-	while (numXBlocks * blockSize < minStride)
-	{
-		++numXBlocks;
-	}
+	/* Count number of blocks required to store the given width.
+	 * And then multiple it with bytes required to store a block.
+	 */
+	stride = (width + blockWidth - 1) / blockWidth * blockBytes;
+
+	/* Round the given minimum stride to the next full blocksize.
+	 * (minStride + blockBytes - 1) / blockBytes * blockBytes
+	 */
+	if ( stride < minStride )
+		stride = (minStride + blockBytes - 1) / blockBytes * blockBytes;
 
-	return numXBlocks * blockSize;
+	return stride;
 }
 
 static unsigned get_compressed_image_size(