mirror of
https://github.com/KolibriOS/kolibrios.git
synced 2024-12-23 23:26:49 +03:00
56 lines
1.2 KiB
C
56 lines
1.2 KiB
C
/* sf_ilogb.c -- float version of s_ilogb.c.
|
|
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
|
|
*/
|
|
|
|
/*
|
|
* ====================================================
|
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
|
*
|
|
* Developed at SunPro, a Sun Microsystems, Inc. business.
|
|
* Permission to use, copy, modify, and distribute this
|
|
* software is freely granted, provided that this notice
|
|
* is preserved.
|
|
* ====================================================
|
|
*/
|
|
|
|
#include <limits.h>
|
|
#include "fdlibm.h"
|
|
|
|
#ifdef __STDC__
|
|
int ilogbf(float x)
|
|
#else
|
|
int ilogbf(x)
|
|
float x;
|
|
#endif
|
|
{
|
|
__int32_t hx,ix;
|
|
|
|
GET_FLOAT_WORD(hx,x);
|
|
hx &= 0x7fffffff;
|
|
if(FLT_UWORD_IS_ZERO(hx))
|
|
return FP_ILOGB0; /* ilogb(0) = special case error */
|
|
if(FLT_UWORD_IS_SUBNORMAL(hx)) {
|
|
for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
|
|
return ix;
|
|
}
|
|
#if FP_ILOGBNAN != INT_MAX
|
|
else if (FLT_UWORD_IS_NAN(hx)) return FP_ILOGBNAN; /* NAN */
|
|
#endif
|
|
else if (!FLT_UWORD_IS_FINITE(hx)) return INT_MAX;
|
|
else return (hx>>23)-127;
|
|
}
|
|
|
|
#ifdef _DOUBLE_IS_32BITS
|
|
|
|
#ifdef __STDC__
|
|
int ilogb(double x)
|
|
#else
|
|
int ilogb(x)
|
|
double x;
|
|
#endif
|
|
{
|
|
return ilogbf((float) x);
|
|
}
|
|
|
|
#endif /* defined(_DOUBLE_IS_32BITS) */
|