glsl: Add utility function to round and pack int64_t value

Reviewed-by: Elie Tournier <tournier.elie@gmail.com>
Signed-off-by: Sagar Ghuge <sagar.ghuge@intel.com>
This commit is contained in:
Sagar Ghuge
2018-12-11 11:19:38 -08:00
committed by Matt Turner
parent 5a674fd789
commit 21e9bb2b3f

View File

@@ -483,6 +483,42 @@ __roundAndPackUInt64(uint zSign, uint zFrac0, uint zFrac1, uint zFrac2)
(zSign !=0u && (zFrac0 | zFrac1) != 0u));
}
int64_t
__roundAndPackInt64(uint zSign, uint zFrac0, uint zFrac1, uint zFrac2)
{
bool roundNearestEven;
bool increment;
int64_t default_NegNaN = -0x7FFFFFFFFFFFFFFEL;
int64_t default_PosNaN = 0xFFFFFFFFFFFFFFFFL;
roundNearestEven = FLOAT_ROUNDING_MODE == FLOAT_ROUND_NEAREST_EVEN;
if (zFrac2 >= 0x80000000u)
increment = false;
if (!roundNearestEven) {
if (zSign != 0u) {
increment = ((FLOAT_ROUNDING_MODE == FLOAT_ROUND_DOWN) &&
(zFrac2 != 0u));
} else {
increment = (FLOAT_ROUNDING_MODE == FLOAT_ROUND_UP) &&
(zFrac2 != 0u);
}
}
if (increment) {
__add64(zFrac0, zFrac1, 0u, 1u, zFrac0, zFrac1);
if ((zFrac0 | zFrac1) != 0u)
zFrac1 &= ~(1u) + uint(zFrac2 == 0u) & uint(roundNearestEven);
}
int64_t absZ = mix(int64_t(packUint2x32(uvec2(zFrac1, zFrac0))),
-int64_t(packUint2x32(uvec2(zFrac1, zFrac0))),
(zSign != 0u));
int64_t nan = mix(default_PosNaN, default_NegNaN, bool(zSign));
return mix(absZ, nan, bool(zSign ^ uint(absZ < 0)) && bool(absZ));
}
/* Returns the number of leading 0 bits before the most-significant 1 bit of
* `a'. If `a' is zero, 32 is returned.
*/