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authorJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
committerJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
commit0ecb606cb6cf65de1d9fc8a919bceb4be476c602 (patch)
tree2ea1f8305970753e4a657acb2ccc15ca3eec8e2c /math/s_nextafter.c
parent7d58530341304d403a6626d7f7a1913165fe2f32 (diff)
downloadglibc-0ecb606cb6cf65de1d9fc8a919bceb4be476c602.tar.gz
2.5-18.1
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diff --git a/math/s_nextafter.c b/math/s_nextafter.c
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+/* @(#)s_nextafter.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: s_nextafter.c,v 1.8 1995/05/10 20:47:58 jtc Exp $";
+#endif
+
+/* IEEE functions
+ * nextafter(x,y)
+ * return the next machine floating-point number of x in the
+ * direction toward y.
+ * Special cases:
+ */
+
+/* Ugly hack so that the aliasing works. */
+#define __nexttoward __internal___nexttoward
+#define nexttoward __internal_nexttoward
+
+#include <math.h>
+#include <math_private.h>
+#include <float.h>
+
+#ifdef __STDC__
+ double __nextafter(double x, double y)
+#else
+ double __nextafter(x,y)
+ double x,y;
+#endif
+{
+ 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 */
+ double u;
+ INSERT_WORDS(x,hy&0x80000000,1); /* return +-minsubnormal */
+ u = math_opt_barrier (x);
+ u = u*u;
+ math_force_eval (u); /* raise underflow flag */
+ return x;
+ }
+ 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) {
+ x = x+x; /* overflow */
+ if (FLT_EVAL_METHOD != 0 && FLT_EVAL_METHOD != 1)
+ asm ("" : "+m"(x));
+ return x; /* overflow */
+ }
+ if(hy<0x00100000) {
+ double u = x*x; /* underflow */
+ math_force_eval (u); /* raise underflow flag */
+ }
+ INSERT_WORDS(x,hx,lx);
+ return x;
+}
+weak_alias (__nextafter, nextafter)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__nextafter, __nextafterl)
+weak_alias (__nextafter, nextafterl)
+strong_alias (__nextafter, __nexttowardl)
+weak_alias (__nexttowardl, nexttowardl)
+#undef __nexttoward
+strong_alias (__nextafter, __nexttoward)
+#undef nexttoward
+weak_alias (__nextafter, nexttoward)
+#endif