GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libm/src/s_remquof.c Lines: 0 58 0.0 %
Date: 2017-11-13 Branches: 0 44 0.0 %

Line Branch Exec Source
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/* @(#)e_fmod.c 1.3 95/01/18 */
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/*-
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 * ====================================================
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 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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 *
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 * Developed at SunSoft, a Sun Microsystems, Inc. business.
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 * Permission to use, copy, modify, and distribute this
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 * software is freely granted, provided that this notice
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 * is preserved.
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 * ====================================================
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 */
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#include "math.h"
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#include "math_private.h"
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static const float Zero[] = {0.0, -0.0,};
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/*
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 * Return the IEEE remainder and set *quo to the last n bits of the
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 * quotient, rounded to the nearest integer.  We choose n=31 because
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 * we wind up computing all the integer bits of the quotient anyway as
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 * a side-effect of computing the remainder by the shift and subtract
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 * method.  In practice, this is far more bits than are needed to use
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 * remquo in reduction algorithms.
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 */
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float
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remquof(float x, float y, int *quo)
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{
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	int32_t n,hx,hy,hz,ix,iy,sx,i;
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	u_int32_t q,sxy;
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	GET_FLOAT_WORD(hx,x);
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	GET_FLOAT_WORD(hy,y);
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	sxy = (hx ^ hy) & 0x80000000;
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	sx = hx&0x80000000;		/* sign of x */
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	hx ^=sx;		/* |x| */
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	hy &= 0x7fffffff;	/* |y| */
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    /* purge off exception values */
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	if(hy==0||hx>=0x7f800000||hy>0x7f800000) /* y=0,NaN;or x not finite */
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	    return (x*y)/(x*y);
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	if(hx<hy) {
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	    q = 0;
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	    goto fixup;	/* |x|<|y| return x or x-y */
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	} else if(hx==hy) {
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	    *quo = 1;
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	    return Zero[(u_int32_t)sx>>31];	/* |x|=|y| return x*0*/
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	}
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    /* determine ix = ilogb(x) */
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	if(hx<0x00800000) {	/* subnormal x */
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	    for (ix = -126,i=(hx<<8); i>0; i<<=1) ix -=1;
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	} else ix = (hx>>23)-127;
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    /* determine iy = ilogb(y) */
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	if(hy<0x00800000) {	/* subnormal y */
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	    for (iy = -126,i=(hy<<8); i>0; i<<=1) iy -=1;
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	} else iy = (hy>>23)-127;
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    /* set up {hx,lx}, {hy,ly} and align y to x */
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	if(ix >= -126)
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	    hx = 0x00800000|(0x007fffff&hx);
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	else {		/* subnormal x, shift x to normal */
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	    n = -126-ix;
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	    hx <<= n;
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	}
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	if(iy >= -126)
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	    hy = 0x00800000|(0x007fffff&hy);
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	else {		/* subnormal y, shift y to normal */
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	    n = -126-iy;
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	    hy <<= n;
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	}
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    /* fix point fmod */
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	n = ix - iy;
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	q = 0;
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	while(n--) {
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	    hz=hx-hy;
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	    if(hz<0) hx = hx << 1;
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	    else {hx = hz << 1; q++;}
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	    q <<= 1;
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	}
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	hz=hx-hy;
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	if(hz>=0) {hx=hz;q++;}
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    /* convert back to floating value and restore the sign */
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	if(hx==0) {				/* return sign(x)*0 */
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	    *quo = (sxy ? -q : q);
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	    return Zero[(u_int32_t)sx>>31];
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	}
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	while(hx<0x00800000) {		/* normalize x */
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	    hx <<= 1;
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	    iy -= 1;
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	}
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	if(iy>= -126) {		/* normalize output */
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	    hx = ((hx-0x00800000)|((iy+127)<<23));
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	} else {		/* subnormal output */
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	    n = -126 - iy;
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	    hx >>= n;
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	}
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fixup:
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	SET_FLOAT_WORD(x,hx);
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	y = fabsf(y);
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	if (y < 0x1p-125f) {
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	    if (x+x>y || (x+x==y && (q & 1))) {
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		q++;
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		x-=y;
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	    }
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	} else if (x>0.5f*y || (x==0.5f*y && (q & 1))) {
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	    q++;
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	    x-=y;
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	}
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	GET_FLOAT_WORD(hx,x);
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	SET_FLOAT_WORD(x,hx^sx);
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	q &= 0x7fffffff;
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	*quo = (sxy ? -q : q);
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	return x;
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}