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

Revision 1.12, Mon May 20 19:40:09 2013 UTC (10 years, 10 months ago) by joerg
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, prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, phil-wifi, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-merge-20190127, pgoyette-compat-base, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, pgoyette-compat, perseant-stdc-iso10646-base, perseant-stdc-iso10646, netbsd-9-base, netbsd-9-3-RELEASE, netbsd-9-2-RELEASE, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-8-base, netbsd-8-2-RELEASE, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, netbsd-8, netbsd-7-nhusb-base-20170116, netbsd-7-nhusb-base, netbsd-7-nhusb, netbsd-7-base, netbsd-7-2-RELEASE, netbsd-7-1-RELEASE, netbsd-7-1-RC2, netbsd-7-1-RC1, netbsd-7-1-2-RELEASE, netbsd-7-1-1-RELEASE, netbsd-7-1, netbsd-7-0-RELEASE, netbsd-7-0-RC3, netbsd-7-0-RC2, netbsd-7-0-RC1, netbsd-7-0-2-RELEASE, netbsd-7-0-1-RELEASE, netbsd-7-0, netbsd-7, netbsd-10-base, netbsd-10-0-RC6, netbsd-10-0-RC5, netbsd-10-0-RC4, netbsd-10-0-RC3, netbsd-10-0-RC2, netbsd-10-0-RC1, netbsd-10, matt-nb8-mediatek-base, matt-nb8-mediatek, localcount-20160914, is-mlppp-base, is-mlppp, cjep_sun2x-base1, cjep_sun2x-base, cjep_sun2x, cjep_staticlib_x-base1, cjep_staticlib_x-base, cjep_staticlib_x, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan, HEAD
Changes since 1.11: +2 -2 lines

Fix ldexp aliases.

/* s_scalbnf.c -- float version of s_scalbn.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_scalbnf.c,v 1.12 2013/05/20 19:40:09 joerg Exp $");
#endif

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

#ifndef _LP64
__strong_alias(_scalbnf, _scalblnf)
#endif
__weak_alias(scalbnf, _scalbnf)
__weak_alias(scalblnf, _scalblnf)
__weak_alias(ldexpf, _scalbnf)

static const float
two25   =  0x1.0p25,	/* 0x4c000000 */
twom25  =  0x1.0p-25,	/* 0x33000000 */
huge   = 1.0e+30,
tiny   = 1.0e-30;

#ifdef _LP64
float
scalbnf(float x, int n)
{
	return scalblnf(x, n);
}
#endif

float
scalblnf(float x, long n)
{
	int32_t k,ix;
	GET_FLOAT_WORD(ix,x);
        k = (ix&0x7f800000)>>23;		/* extract exponent */
        if (k==0) {				/* 0 or subnormal x */
            if ((ix&0x7fffffff)==0) return x; /* +-0 */
	    x *= two25;
	    GET_FLOAT_WORD(ix,x);
	    k = ((ix&0x7f800000)>>23) - 25;
            if (n< -50000) return tiny*x; 	/*underflow*/
	    }
        if (k==0xff) return x+x;		/* NaN or Inf */
        k = k+n;
        if (k >  0xfe) return huge*copysignf(huge,x); /* overflow  */
        if (k > 0) 				/* normal result */
	    {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
        if (k <= -25) {
            if (n > 50000) 	/* in case integer overflow in n+k */
		return huge*copysignf(huge,x);	/*overflow*/
	    else return tiny*copysignf(tiny,x);	/*underflow*/
	}
        k += 25;				/* subnormal result */
	SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));
        return x*twom25;
}