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-rw-r--r--src/mesa/main/image.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/src/mesa/main/image.c b/src/mesa/main/image.c
index 4b08c065c4c..2d4f3014e21 100644
--- a/src/mesa/main/image.c
+++ b/src/mesa/main/image.c
@@ -1,4 +1,4 @@
-/* $Id: image.c,v 1.40 2000/09/12 21:10:25 brianp Exp $ */
+/* $Id: image.c,v 1.41 2000/09/14 23:13:51 brianp Exp $ */
/*
* Mesa 3-D graphics library
@@ -63,6 +63,11 @@ const struct gl_pixelstore_attrib _mesa_native_packing = {
/*
* Flip the 8 bits in each byte of the given array.
+ *
+ * XXX try this trick to flip bytes someday:
+ * v = ((v & 0x55555555) << 1) | ((v >> 1) & 0x55555555);
+ * v = ((v & 0x33333333) << 2) | ((v >> 2) & 0x33333333);
+ * v = ((v & 0x0f0f0f0f) << 4) | ((v >> 4) & 0x0f0f0f0f);
*/
static void
flip_bytes( GLubyte *p, GLuint n )
@@ -70,7 +75,7 @@ flip_bytes( GLubyte *p, GLuint n )
register GLuint i, a, b;
for (i=0;i<n;i++) {
- b = (GLuint) p[i];
+ b = (GLuint) p[i]; /* words are often faster than bytes */
a = ((b & 0x01) << 7) |
((b & 0x02) << 5) |
((b & 0x04) << 3) |