20060303a

1 files changed, 88 insertions, 0 deletions

diff --git a/libmath/fdlibm/s_rint.c b/libmath/fdlibm/s_rint.c
new file mode 100644
index 00000000..508ade7a
--- /dev/null
+++ b/libmath/fdlibm/s_rint.c
@@ -0,0 +1,88 @@
+/* derived from /netlib/fdlibm */
+
+/* @(#)s_rint.c 1.3 95/01/18 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice 
+ * is preserved.
+ * ====================================================
+ */
+
+/* dummy routine to get around over-eager arm compiler optimization.
+  * Calling this causes a store and reload of floating point numbers
+  */
+
+void
+dummy(void)
+{
+}
+
+
+/*
+ * rint(x)
+ * Return x rounded to integral value according to the prevailing
+ * rounding mode.
+ * Method:
+ *	Using floating addition.
+ * Exception:
+ *	Inexact flag raised if x not equal to rint(x).
+ */
+
+#include "fdlibm.h"
+
+static const double
+TWO52[2]={
+  4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
+ -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
+};
+
+	double rint(double x)
+{
+	int i0,j0,sx;
+	unsigned i,i1;
+	double w,t;
+	i0 =  __HI(x);
+	sx = (i0>>31)&1;
+	i1 =  __LO(x);
+	j0 = ((i0>>20)&0x7ff)-0x3ff;
+	if(j0<20) {
+	    if(j0<0) { 	
+		if(((i0&0x7fffffff)|i1)==0) return x;
+		i1 |= (i0&0x0fffff);
+		i0 &= 0xfffe0000;
+		i0 |= ((i1|-i1)>>12)&0x80000;
+		__HI(x)=i0;
+	        w = TWO52[sx]+x;
+                 dummy();			/* fix optimiser */
+	        t =  w-TWO52[sx];
+	        i0 = __HI(t);
+	        __HI(t) = (i0&0x7fffffff)|(sx<<31);
+	        return t;
+	    } else {
+		i = (0x000fffff)>>j0;
+		if(((i0&i)|i1)==0) return x; /* x is integral */
+		i>>=1;
+		if(((i0&i)|i1)!=0) {
+		    if(j0==19) i1 = 0x40000000; else
+		    i0 = (i0&(~i))|((0x20000)>>j0);
+		}
+	    }
+	} else if (j0>51) {
+	    if(j0==0x400) return x+x;	/* inf or NaN */
+	    else return x;		/* x is integral */
+	} else {
+	    i = ((unsigned)(0xffffffff))>>(j0-20);
+	    if((i1&i)==0) return x;	/* x is integral */
+	    i>>=1;
+	    if((i1&i)!=0) i1 = (i1&(~i))|((0x40000000)>>(j0-20));
+	}
+	__HI(x) = i0;
+	__LO(x) = i1;
+	w = TWO52[sx]+x;
+	dummy();			/* fix optimiser */
+	return w-TWO52[sx];
+}