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File: [cvs.NetBSD.org] / src / lib / libm / src / s_ilogbf.c (download)

Revision 1.8, Sat Feb 9 22:56:00 2013 UTC (21 months, 1 week ago) by matt
Branch: MAIN
CVS Tags: yamt-pagecache-base9, tls-maxphys-base, tls-earlyentropy-base, tls-earlyentropy, riastradh-xf86-video-intel-2-7-1-pre-2-21-15, riastradh-drm2-base3, riastradh-drm2-base2, riastradh-drm2-base1, riastradh-drm2-base, riastradh-drm2, netbsd-7-base, netbsd-7, agc-symver-base, agc-symver, HEAD
Changes since 1.7: +3 -3 lines

Use FP_ILOGB0 and FP_ILOGBNAN

/* s_ilogbf.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 <sys/cdefs.h>
#if defined(LIBM_SCCS) && !defined(lint)
__RCSID("$NetBSD: s_ilogbf.c,v 1.8 2013/02/09 22:56:00 matt Exp $");
#endif

#include "math.h"
#include "math_private.h"

int
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) = 0x80000001 */
	    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 return FP_ILOGBNAN;	/* inf too */
}