1 files changed, 73 insertions, 0 deletions
diff --git a/libm/src/s_nexttoward.c b/libm/src/s_nexttoward.c
new file mode 100644
index 0000000..55da4ad
--- /dev/null
+++ b/libm/src/s_nexttoward.c
@@ -0,0 +1,73 @@
+/* @(#)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.
+ * ====================================================
+ */
+
+#ifndef lint
+static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_nexttoward.c,v 1.1 2005/03/07 04:56:46 das Exp $";
+#endif
+
+/*
+ * We assume that a long double has a 15-bit exponent.  On systems
+ * where long double is the same as double, nexttoward() is an alias
+ * for nextafter(), so we don't use this routine.
+ */
+
+#include <float.h>
+
+#include "fpmath.h"
+#include "math.h"
+#include "math_private.h"
+
+#if LDBL_MAX_EXP != 0x4000
+#error "Unsupported long double format"
+#endif
+
+double
+nexttoward(double x, long double y)
+{
+	union IEEEl2bits uy;
+	volatile double t;
+	int32_t hx,ix;
+	u_int32_t lx;
+
+	EXTRACT_WORDS(hx,lx,x);
+	ix = hx&0x7fffffff;		/* |x| */
+	uy.e = y;
+
+	if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) ||
+	    (uy.bits.exp == 0x7fff &&
+	     ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl) != 0))
+	   return x+y;	/* x or y is nan */
+	if(x==y) return (double)y;		/* x=y, return y */
+	if(x==0.0) {
+	    INSERT_WORDS(x,uy.bits.sign<<31,1);	/* return +-minsubnormal */
+	    t = x*x;
+	    if(t==x) return t; else return x;	/* raise underflow flag */
+	}
+	if(hx>0.0 ^ x < y) {			/* x -= ulp */
+	    if(lx==0) hx -= 1;
+	    lx -= 1;
+	} else {				/* x += ulp */
+	    lx += 1;
+	    if(lx==0) hx += 1;
+	}
+	ix = hx&0x7ff00000;
+	if(ix>=0x7ff00000) return x+x;	/* overflow  */
+	if(ix<0x00100000) {		/* underflow */
+	    t = x*x;
+	    if(t!=x) {		/* raise underflow flag */
+	        INSERT_WORDS(y,hx,lx);
+		return y;
+	    }
+	}
+	INSERT_WORDS(x,hx,lx);
+	return x;
+}