Totally rework the math library, this time based on the MacOs X

math library (which is itself based on the math lib from FreeBSD).
 -Erik

1 files changed, 79 insertions, 0 deletions

diff --git a/libm/s_nextafter.c b/libm/s_nextafter.c
new file mode 100644
index 000000000..2a9c6f490
--- /dev/null
+++ b/libm/s_nextafter.c
@@ -0,0 +1,79 @@
+/* @(#)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:
+ */
+
+#include "math.h"
+#include "math_private.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 x;		/* x=y, return x */
+	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;
+}