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Revision 1.7, Sun May 26 22:01:49 2002 UTC (21 years, 10 months ago) by wiz
Branch: MAIN
CVS Tags: yamt-pf42-baseX, yamt-pf42-base4, yamt-pf42-base3, yamt-pf42-base2, yamt-pf42-base, yamt-pf42, yamt-pagecache-tag8, yamt-pagecache-base9, yamt-pagecache-base8, yamt-pagecache-base7, yamt-pagecache-base6, yamt-pagecache-base5, yamt-pagecache-base4, yamt-pagecache-base3, yamt-pagecache-base2, yamt-pagecache-base, yamt-pagecache, wrstuden-revivesa-base-3, wrstuden-revivesa-base-2, wrstuden-revivesa-base-1, wrstuden-revivesa-base, wrstuden-revivesa, wrstuden-fixsa-newbase, wrstuden-fixsa-base-1, wrstuden-fixsa-base, wrstuden-fixsa, tls-maxphys-base, tls-maxphys, 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, 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hpcarm-cleanup, fvdl_fs64_base, cube-autoconf-base, cube-autoconf, cjep_sun2x-base1, cjep_sun2x-base, cjep_sun2x, cjep_staticlib_x-base1, cjep_staticlib_x-base, cjep_staticlib_x, cherry-xenmp-base, cherry-xenmp, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan, bouyer-quota2-nbase, bouyer-quota2-base, bouyer-quota2, agc-symver-base, agc-symver, abandoned-netbsd-4-base, abandoned-netbsd-4, HEAD
Changes since 1.6: +3 -11 lines 

__STDC__ is always defined on NetBSD.

/* e_fmodf.c -- float version of e_fmod.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: e_fmodf.c,v 1.7 2002/05/26 22:01:49 wiz Exp $");
#endif

/*
 * __ieee754_fmodf(x,y)
 * Return x mod y in exact arithmetic
 * Method: shift and subtract
 */

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

static const float one = 1.0, Zero[] = {0.0, -0.0,};

float
__ieee754_fmodf(float x, float y)
{
	int32_t n,hx,hy,hz,ix,iy,sx,i;

	GET_FLOAT_WORD(hx,x);
	GET_FLOAT_WORD(hy,y);
	sx = hx&0x80000000;		/* sign of x */
	hx ^=sx;		/* |x| */
	hy &= 0x7fffffff;	/* |y| */

    /* purge off exception values */
	if(hy==0||(hx>=0x7f800000)||		/* y=0,or x not finite */
	   (hy>0x7f800000))			/* or y is NaN */
	    return (x*y)/(x*y);
	if(hx<hy) return x;			/* |x|<|y| return x */
	if(hx==hy)
	    return Zero[(u_int32_t)sx>>31];	/* |x|=|y| return x*0*/

    /* determine ix = ilogb(x) */
	if(hx<0x00800000) {	/* subnormal x */
	    for (ix = -126,i=(hx<<8); i>0; i<<=1) ix -=1;
	} else ix = (hx>>23)-127;

    /* determine iy = ilogb(y) */
	if(hy<0x00800000) {	/* subnormal y */
	    for (iy = -126,i=(hy<<8); i>=0; i<<=1) iy -=1;
	} else iy = (hy>>23)-127;

    /* set up {hx,lx}, {hy,ly} and align y to x */
	if(ix >= -126)
	    hx = 0x00800000|(0x007fffff&hx);
	else {		/* subnormal x, shift x to normal */
	    n = -126-ix;
	    hx = hx<<n;
	}
	if(iy >= -126)
	    hy = 0x00800000|(0x007fffff&hy);
	else {		/* subnormal y, shift y to normal */
	    n = -126-iy;
	    hy = hy<<n;
	}

    /* fix point fmod */
	n = ix - iy;
	while(n--) {
	    hz=hx-hy;
	    if(hz<0){hx = hx+hx;}
	    else {
	    	if(hz==0) 		/* return sign(x)*0 */
		    return Zero[(u_int32_t)sx>>31];
	    	hx = hz+hz;
	    }
	}
	hz=hx-hy;
	if(hz>=0) {hx=hz;}

    /* convert back to floating value and restore the sign */
	if(hx==0) 			/* return sign(x)*0 */
	    return Zero[(u_int32_t)sx>>31];
	while(hx<0x00800000) {		/* normalize x */
	    hx = hx+hx;
	    iy -= 1;
	}
	if(iy>= -126) {		/* normalize output */
	    hx = ((hx-0x00800000)|((iy+127)<<23));
	    SET_FLOAT_WORD(x,hx|sx);
	} else {		/* subnormal output */
	    n = -126 - iy;
	    hx >>= n;
	    SET_FLOAT_WORD(x,hx|sx);
	    x *= one;		/* create necessary signal */
	}
	return x;		/* exact output */
}