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/* s_ilogbf.c -- float version of s_ilogb.c.
*/
/*
* ====================================================
* 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.
* ====================================================
*/
#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: s_ilogbf.c,v 1.4 1995/05/10 20:47:31 jtc Exp $";
#endif
#include <limits.h>
#include <math.h>
#include <math_private.h>
int __ieee754_ilogbf(float x)
{
int32_t hx,ix;
GET_FLOAT_WORD(hx,x);
hx &= 0x7fffffff;
if(hx<0x00800000) {
if(hx==0)
return FP_ILOGB0; /* ilogb(0) = FP_ILOGB0 */
else /* subnormal x */
for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
return ix;
}
else if (hx<0x7f800000) return (hx>>23)-127;
else if (FP_ILOGBNAN != INT_MAX) {
/* ISO C99 requires ilogbf(+-Inf) == INT_MAX. */
if (hx==0x7f800000)
return INT_MAX;
}
return FP_ILOGBNAN;
}
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