import newlib-2000-02-17 snapshotnewlib-2000-02-17SNAPSHOT

1 files changed, 93 insertions, 0 deletions

diff --git a/newlib/libm/common/sf_cbrt.c b/newlib/libm/common/sf_cbrt.c
new file mode 100644
index 00000000000..c053d9548ba
--- /dev/null
+++ b/newlib/libm/common/sf_cbrt.c
@@ -0,0 +1,93 @@
+/* sf_cbrt.c -- float version of s_cbrt.c.
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ *
+ */
+
+#include "fdlibm.h"
+
+/* cbrtf(x)
+ * Return cube root of x
+ */
+#ifdef __STDC__
+static const __uint32_t 
+#else
+static __uint32_t 
+#endif
+	B1 = 709958130, /* B1 = (84+2/3-0.03306235651)*2**23 */
+	B2 = 642849266; /* B2 = (76+2/3-0.03306235651)*2**23 */
+
+#ifdef __STDC__
+static const float
+#else
+static float
+#endif
+C =  5.4285717010e-01, /* 19/35     = 0x3f0af8b0 */
+D = -7.0530611277e-01, /* -864/1225 = 0xbf348ef1 */
+E =  1.4142856598e+00, /* 99/70     = 0x3fb50750 */
+F =  1.6071428061e+00, /* 45/28     = 0x3fcdb6db */
+G =  3.5714286566e-01; /* 5/14      = 0x3eb6db6e */
+
+#ifdef __STDC__
+	float cbrtf(float x) 
+#else
+	float cbrtf(x) 
+	float x;
+#endif
+{
+	__int32_t	hx;
+	float r,s,t;
+	__uint32_t sign;
+	__uint32_t high;
+
+	GET_FLOAT_WORD(hx,x);
+	sign=hx&0x80000000; 		/* sign= sign(x) */
+	hx  ^=sign;
+	if(hx>=0x7f800000) return(x+x); /* cbrt(NaN,INF) is itself */
+	if(hx==0) 
+	    return(x);		/* cbrt(0) is itself */
+
+	SET_FLOAT_WORD(x,hx);	/* x <- |x| */
+    /* rough cbrt to 5 bits */
+	if(hx<0x00800000) 		/* subnormal number */
+	  {SET_FLOAT_WORD(t,0x4b800000); /* set t= 2**24 */
+	   t*=x; GET_FLOAT_WORD(high,t); SET_FLOAT_WORD(t,high/3+B2);
+	  }
+	else
+	  SET_FLOAT_WORD(t,hx/3+B1);
+
+
+    /* new cbrt to 23 bits */
+	r=t*t/x;
+	s=C+r*t;
+	t*=G+F/(s+E+D/s);	
+
+    /* retore the sign bit */
+	GET_FLOAT_WORD(high,t);
+	SET_FLOAT_WORD(t,high|sign);
+	return(t);
+}
+
+#ifdef _DOUBLE_IS_32BITS
+
+#ifdef __STDC__
+	double cbrt(double x)
+#else
+	double cbrt(x)
+	double x;
+#endif
+{
+	return (double) cbrtf((float) x);
+}
+
+#endif /* defined(_DOUBLE_IS_32BITS) */