20060303a

1 files changed, 70 insertions, 0 deletions

diff --git a/libmath/fdlibm/s_ceil.c b/libmath/fdlibm/s_ceil.c
new file mode 100644
index 00000000..7bb2a00c
--- /dev/null
+++ b/libmath/fdlibm/s_ceil.c
@@ -0,0 +1,70 @@
+/* derived from /netlib/fdlibm */
+
+/* @(#)s_ceil.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.
+ * ====================================================
+ */
+
+/*
+ * ceil(x)
+ * Return x rounded toward -inf to integral value
+ * Method:
+ *	Bit twiddling.
+ * Exception:
+ *	Inexact flag raised if x not equal to ceil(x).
+ */
+
+#include "fdlibm.h"
+
+static const double Huge = 1.0e300;
+
+	double ceil(double x)
+{
+	int i0,i1,j0;
+	unsigned i,j;
+	i0 =  __HI(x);
+	i1 =  __LO(x);
+	j0 = ((i0>>20)&0x7ff)-0x3ff;
+	if(j0<20) {
+	    if(j0<0) { 	/* raise inexact if x != 0 */
+		if(Huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
+		    if(i0<0) {i0=0x80000000;i1=0;} 
+		    else if((i0|i1)!=0) { i0=0x3ff00000;i1=0;}
+		}
+	    } else {
+		i = (0x000fffff)>>j0;
+		if(((i0&i)|i1)==0) return x; /* x is integral */
+		if(Huge+x>0.0) {	/* raise inexact flag */
+		    if(i0>0) i0 += (0x00100000)>>j0;
+		    i0 &= (~i); i1=0;
+		}
+	    }
+	} 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 */
+	    if(Huge+x>0.0) { 		/* raise inexact flag */
+		if(i0>0) {
+		    if(j0==20) i0+=1; 
+		    else {
+			j = i1 + (1<<(52-j0));
+			if(j<i1) i0+=1;	/* got a carry */
+			i1 = j;
+		    }
+		}
+		i1 &= (~i);
+	    }
+	}
+	__HI(x) = i0;
+	__LO(x) = i1;
+	return x;
+}