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util: Added functions for checking NaN / Inf for double and half-floats.

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Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
This commit is contained in:
James Benton 2012-05-22 14:53:30 +01:00 • committed by José Fonseca
parent 34075d4133
commit d069d8ef38
1 changed files with 102 additions and 2 deletions
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104
src/gallium/auxiliary/util/u_math.h
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@ -183,6 +183,13 @@ union fi {
};
union di {
double d;
int64_t i;
uint64_t ui;
};
/**
* Fast version of 2^x
* Identity: exp2(a + b) = exp2(a) * exp2(b)
@ -325,14 +332,107 @@ util_is_approx(float a, float b, float tol)
/**
* Test if x is NaN or +/- infinity.
* util_is_X_inf_or_nan = test if x is NaN or +/- Inf
* util_is_X_nan = test if x is NaN
* util_X_inf_sign = return +1 for +Inf, -1 for -Inf, or 0 for not Inf
*
* NaN can be checked with x != x, however this fails with the fast math flag
**/
/**
* Single-float
*/
static INLINE boolean
util_is_inf_or_nan(float x)
{
union fi tmp;
tmp.f = x;
return !(int)((unsigned int)((tmp.i & 0x7fffffff)-0x7f800000) >> 31);
return (tmp.ui & 0x7f800000) == 0x7f800000;
}
static INLINE boolean
util_is_nan(float x)
{
union fi tmp;
tmp.f = x;
return (tmp.ui & 0x7fffffff) > 0x7f800000;
}
static INLINE int
util_inf_sign(float x)
{
union fi tmp;
tmp.f = x;
if ((tmp.ui & 0x7fffffff) != 0x7f800000) {
return 0;
}
return (x < 0) ? -1 : 1;
}
/**
* Double-float
*/
static INLINE boolean
util_is_double_inf_or_nan(double x)
{
union di tmp;
tmp.d = x;
return (tmp.ui & 0x7ff0000000000000) == 0x7ff0000000000000;
}
static INLINE boolean
util_is_double_nan(double x)
{
union di tmp;
tmp.d = x;
return (tmp.ui & 0x7fffffffffffffff) > 0x7ff0000000000000;
}
static INLINE int
util_double_inf_sign(double x)
{
union di tmp;
tmp.d = x;
if ((tmp.ui & 0x7fffffffffffffff) != 0x7ff0000000000000) {
return 0;
}
return (x < 0) ? -1 : 1;
}
/**
* Half-float
*/
static INLINE boolean
util_is_half_inf_or_nan(int16_t x)
{
return (x & 0x7c00) == 0x7c00;
}
static INLINE boolean
util_is_half_nan(int16_t x)
{
return (x & 0x7fff) > 0x7c00;
}
static INLINE int
util_half_inf_sign(int16_t x)
{
if ((x & 0x7fff) != 0x7c00) {
return 0;
}
return (x < 0) ? -1 : 1;
}