commit 65026f980a6df01a7d437ce51a47de911820041e
author Bhanu Chetlapalli <bhanu@mips.com> Wed Jan 25 14:45:30 2012 -0800
committer Bhanu Chetlapalli <bhanu@mips.com> Wed Jan 25 14:45:30 2012 -0800
tree ea4b70a8a4fcc4b1f88e83a86136001b620cbc62
parent 149ae11fb63818b470156e1652abfad0e08d486d

Prevent bit shifting if num bits is negative

Causes OpenGL Software Renderer to generate incorrect window
coordinates on MIPS & possibly x86

Change-Id: I3c51b6a5a4e6af75e9b31d9d47e4e4d894825888
Signed-off-by: Bhanu Chetlapalli <bhanu@mips.com>

libpixelflinger/fixed.cpp

diff --git a/libpixelflinger/fixed.cpp b/libpixelflinger/fixed.cpp
index 5b92062..5094537 100644
--- a/libpixelflinger/fixed.cpp
+++ b/libpixelflinger/fixed.cpp
@@ -62,7 +62,8 @@
     int shift;
     x = gglRecipQNormalized(x, &shift);
     shift += 16-q;
-    x += 1L << (shift-1);   // rounding
+    if (shift > 0)
+        x += 1L << (shift-1);   // rounding
     x >>= shift;
     return x;
 }