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120 lines
2.9 KiB
C
120 lines
2.9 KiB
C
/* s_nextafterl.c -- long double version of s_nextafter.c.
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* Special version for i387.
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* Conversion to long double by Ulrich Drepper,
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* Cygnus Support, drepper@cygnus.com.
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*/
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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 SunPro, 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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#if defined(LIBM_SCCS) && !defined(lint)
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static char rcsid[] = "$NetBSD: $";
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#endif
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/* IEEE functions
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* nextafterl(x,y)
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* return the next machine floating-point number of x in the
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* direction toward y.
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* Special cases:
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*/
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#include "math.h"
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#include <math_private.h>
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long double __nextafterl(long double x, long double y)
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{
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u_int32_t hx,hy,ix,iy;
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u_int32_t lx,ly;
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int32_t esx,esy;
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GET_LDOUBLE_WORDS(esx,hx,lx,x);
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GET_LDOUBLE_WORDS(esy,hy,ly,y);
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ix = esx&0x7fff; /* |x| */
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iy = esy&0x7fff; /* |y| */
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/* Intel's extended format has the normally implicit 1 explicit
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present. Sigh! */
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if(((ix==0x7fff)&&(((hx&0x7fffffff)|lx)!=0)) || /* x is nan */
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((iy==0x7fff)&&(((hy&0x7fffffff)|ly)!=0))) /* y is nan */
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return x+y;
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if(x==y) return y; /* x=y, return y */
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if((ix|hx|lx)==0) { /* x == 0 */
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long double u;
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SET_LDOUBLE_WORDS(x,esy&0x8000,0,1);/* return +-minsubnormal */
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u = math_opt_barrier (x);
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u = u * u;
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math_force_eval (u); /* raise underflow flag */
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return x;
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}
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if(esx>=0) { /* x > 0 */
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if(esx>esy||((esx==esy) && (hx>hy||((hx==hy)&&(lx>ly))))) {
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/* x > y, x -= ulp */
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if(lx==0) {
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if (hx <= 0x80000000) {
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if (esx == 0) {
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--hx;
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} else {
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esx -= 1;
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hx = hx - 1;
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if (esx > 0)
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hx |= 0x80000000;
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}
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} else
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hx -= 1;
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}
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lx -= 1;
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} else { /* x < y, x += ulp */
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lx += 1;
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if(lx==0) {
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hx += 1;
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if (hx==0 || (esx == 0 && hx == 0x80000000)) {
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esx += 1;
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hx |= 0x80000000;
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}
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}
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}
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} else { /* x < 0 */
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if(esy>=0||(esx>esy||((esx==esy)&&(hx>hy||((hx==hy)&&(lx>ly)))))){
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/* x < y, x -= ulp */
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if(lx==0) {
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if (hx <= 0x80000000) {
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esx -= 1;
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hx = hx - 1;
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if ((esx&0x7fff) > 0)
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hx |= 0x80000000;
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} else
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hx -= 1;
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}
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lx -= 1;
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} else { /* x > y, x += ulp */
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lx += 1;
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if(lx==0) {
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hx += 1;
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if (hx==0 || (esx == 0xffff8000 && hx == 0x80000000)) {
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esx += 1;
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hx |= 0x80000000;
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}
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}
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}
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}
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esy = esx&0x7fff;
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if(esy==0x7fff) return x+x; /* overflow */
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if(esy==0) {
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long double u = x*x; /* underflow */
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math_force_eval (u); /* raise underflow flag */
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}
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SET_LDOUBLE_WORDS(x,esx,hx,lx);
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return x;
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}
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weak_alias (__nextafterl, nextafterl)
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strong_alias (__nextafterl, __nexttowardl)
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weak_alias (__nextafterl, nexttowardl)
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