reactos/sdk/lib/ucrt/math/_fdclass.c
2025-02-15 20:03:52 -06:00

48 lines
1,005 B
C

//
// _fdclass.c
//
// Copyright (c) 2024 Timo Kreuzer
//
// Implementation of _fdclass.
//
// SPDX-License-Identifier: MIT
//
#include <math.h>
#include <stdint.h>
#if defined(_MSC_VER) && (_MSC_VER >= 1922)
#pragma function(_fdclass)
#endif
//
// Returns the floating-point classification of _X.
//
// FP_NAN - A quiet, signaling, or indeterminate NaN
// FP_INFINITE - A positive or negative infinity
// FP_NORMAL - A positive or negative normalized non-zero value
// FP_SUBNORMAL - A positive or negative subnormal (denormalized) value
// FP_ZERO - A positive or negative zero value
//
_Check_return_
short
__cdecl
_fdclass(_In_ float _X)
{
union { float f; uint32_t ui32; } u = { _X };
uint32_t e = u.ui32 & 0x7F800000u;
uint32_t m = u.ui32 & 0x007FFFFFu;
if (e == 0x7F800000u)
{
return m ? FP_NAN : FP_INFINITE;
}
else if (e == 0)
{
return m ? FP_SUBNORMAL : FP_ZERO;
}
else
{
return FP_NORMAL;
}
}