"Optimise" quantization step by replacing the division by a multiplication.
This has no measurable difference right now but makes it possible to do
SIMD implementations of this stage.
git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@3647 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/common/jpeg/jdct.h b/common/jpeg/jdct.h
index c3650ea..c834410 100644
--- a/common/jpeg/jdct.h
+++ b/common/jpeg/jdct.h
@@ -23,13 +23,18 @@
* have a range of +-8K for 8-bit data, +-128K for 12-bit data. This
* convention improves accuracy in integer implementations and saves some
* work in floating-point ones.
- * Quantization of the output coefficients is done by jcdctmgr.c.
+ * Quantization of the output coefficients is done by jcdctmgr.c. This
+ * step requires an unsigned type and also one with twice the bits.
*/
#if BITS_IN_JSAMPLE == 8
typedef int DCTELEM; /* 16 or 32 bits is fine */
+typedef unsigned int UDCTELEM;
+typedef unsigned long long UDCTELEM2;
#else
typedef INT32 DCTELEM; /* must have 32 bits */
+typedef UINT32 UDCTELEM;
+typedef unsigned long long UDCTELEM2;
#endif