1 files changed, 63 insertions, 0 deletions
diff --git a/libm/src/e_coshf.c b/libm/src/e_coshf.c
new file mode 100644
index 0000000..f9df9b0
--- /dev/null
+++ b/libm/src/e_coshf.c
@@ -0,0 +1,63 @@
+/* e_coshf.c -- float version of e_cosh.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.
+ * ====================================================
+ */
+
+#ifndef lint
+static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_coshf.c,v 1.7 2005/11/13 00:08:23 bde Exp $";
+#endif
+
+#include "math.h"
+#include "math_private.h"
+
+static const float one = 1.0, half=0.5, huge = 1.0e30;
+
+float
+__ieee754_coshf(float x)
+{
+	float t,w;
+	int32_t ix;
+
+	GET_FLOAT_WORD(ix,x);
+	ix &= 0x7fffffff;
+
+    /* x is INF or NaN */
+	if(ix>=0x7f800000) return x*x;
+
+    /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
+	if(ix<0x3eb17218) {
+	    t = expm1f(fabsf(x));
+	    w = one+t;
+	    if (ix<0x39800000) return one;	/* cosh(tiny) = 1 */
+	    return one+(t*t)/(w+w);
+	}
+
+    /* |x| in [0.5*ln2,9], return (exp(|x|)+1/exp(|x|))/2; */
+	if (ix < 0x41100000) {
+		t = __ieee754_expf(fabsf(x));
+		return half*t+half/t;
+	}
+
+    /* |x| in [9, log(maxfloat)] return half*exp(|x|) */
+	if (ix < 0x42b17217)  return half*__ieee754_expf(fabsf(x));
+
+    /* |x| in [log(maxfloat), overflowthresold] */
+	if (ix<=0x42b2d4fc) {
+	    w = __ieee754_expf(half*fabsf(x));
+	    t = half*w;
+	    return t*w;
+	}
+
+    /* |x| > overflowthresold, cosh(x) overflow */
+	return huge*huge;
+}