diff options
| author | Neil Roberts <neil@linux.intel.com> | 2014-09-17 15:47:46 +0100 |
|---|---|---|
| committer | Neil Roberts <neil@linux.intel.com> | 2014-09-18 17:34:04 +0100 |
| commit | 0eed11fd312616617ec865a6f59c0e51f5b187fa (patch) | |
| tree | 134f74d0f7c362b88db9cd75cda12c68f773f316 /tests/texturing | |
| parent | 948af4eb07bdb7b9c868fa22659b70e744e8e6e8 (diff) | |
teximage-color: Fix un_to_float for 32-bit builds
The un_to_float function was trying to get the maximum value given a
number of bits by shifting ~0ul by the number of bits. For the
GL_UNSIGNED_INT type this function was also being used to get a
maximum value for a 32-bit quantity. However on a 32-bit build this
would mean that it is shifting a 32-bit integer (unsigned long is
32-bit) by 32 bits. The C spec leaves it undefined what happens if you
do a shift that is greater than the number of bits in the type. GCC
takes advantage of that to make the shift a no-op so the maximum was
ending up as zero and the test fails.
This patch makes it shift ~0u in the other direction so that it
doesn't matter what size unsigned int is and it won't try to shift by
32.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83695
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Tested-by: Tapani Pälli <tapani.palli@intel.com>
Diffstat (limited to 'tests/texturing')
| -rw-r--r-- | tests/texturing/teximage-colors.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tests/texturing/teximage-colors.c b/tests/texturing/teximage-colors.c index 712e11bbf..2bee02f42 100644 --- a/tests/texturing/teximage-colors.c +++ b/tests/texturing/teximage-colors.c @@ -189,7 +189,7 @@ valid_combination(GLenum format, GLenum type) static float un_to_float(unsigned char bits, unsigned int color) { - unsigned int max = ~(~0ul << bits); + unsigned int max = ~0u >> (sizeof(max) * 8 - bits); return (float)color / (float)max; } |