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- /*
- * ====================================================
- * 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.
- * ====================================================
- */
- /* IEEE functions
- * nextafter(x,y)
- * return the next machine floating-point number of x in the
- * direction toward y.
- * Special cases:
- */
- #include "math.h"
- #include "math_private.h"
- #include <float.h>
- double nextafter(double x, double y)
- {
- int32_t hx,hy,ix,iy;
- u_int32_t lx,ly;
- EXTRACT_WORDS(hx,lx,x);
- EXTRACT_WORDS(hy,ly,y);
- ix = hx&0x7fffffff; /* |x| */
- iy = hy&0x7fffffff; /* |y| */
- if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */
- ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0)) /* y is nan */
- return x+y;
- if(x==y) return y; /* x=y, return y */
- if((ix|lx)==0) { /* x == 0 */
- INSERT_WORDS(x,hy&0x80000000,1); /* return +-minsubnormal */
- y = x*x;
- if(y==x) return y; else return x; /* raise underflow flag */
- }
- if(hx>=0) { /* x > 0 */
- if(hx>hy||((hx==hy)&&(lx>ly))) { /* x > y, x -= ulp */
- if(lx==0) hx -= 1;
- lx -= 1;
- } else { /* x < y, x += ulp */
- lx += 1;
- if(lx==0) hx += 1;
- }
- } else { /* x < 0 */
- if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){/* x < y, x -= ulp */
- if(lx==0) hx -= 1;
- lx -= 1;
- } else { /* x > y, x += ulp */
- lx += 1;
- if(lx==0) hx += 1;
- }
- }
- hy = hx&0x7ff00000;
- if(hy>=0x7ff00000) return x+x; /* overflow */
- if(hy<0x00100000) { /* underflow */
- y = x*x;
- if(y!=x) { /* raise underflow flag */
- INSERT_WORDS(y,hx,lx);
- return y;
- }
- }
- INSERT_WORDS(x,hx,lx);
- return x;
- }
- libm_hidden_def(nextafter)
- #if LDBL_MANT_DIG == DBL_MANT_DIG
- strong_alias_untyped(nextafter, nexttoward)
- libm_hidden_def(nexttoward)
- #else
- double nexttoward(double x, long double y)
- {
- return nextafter(x, y);
- }
- libm_hidden_def(nexttoward)
- #endif
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