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/* @(#)s_nextafter.c 5.1 93/09/24 */ |
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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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/* 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 |
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nextafterl(long double x, long double y) |
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{ |
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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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✓✓✗✓
✓✗ |
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if (((ix==0x7fff)&&(((hx&0x7fffffff)|lx)!=0)) || /* x is nan */ |
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✓✓ |
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((iy==0x7fff)&&(((hy&0x7fffffff)|ly)!=0))) /* y is nan */ |
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return x+y; |
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✓✗ |
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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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volatile long double u; |
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SET_LDOUBLE_WORDS(x,esy&0x8000,0,1);/* return +-minsubnormal */ |
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u = x; |
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u = u * 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&0x7fffffff)==0) esx -= 1; |
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hx = (hx - 1) | (hx & 0x80000000); |
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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 = (hx + 1) | (hx & 0x80000000); |
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if ((hx&0x7fffffff)==0) esx += 1; |
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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&0x7fffffff)==0) esx -= 1; |
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hx = (hx - 1) | (hx & 0x80000000); |
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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 = (hx + 1) | (hx & 0x80000000); |
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if ((hx&0x7fffffff)==0) esx += 1; |
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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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volatile long double u = x*x; /* underflow */ |
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if(u==x) { |
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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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} |
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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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DEF_STD(nextafterl); |
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MAKE_UNUSED_CLONE(nexttowardl, nextafterl); |