1 files changed, 59 insertions, 0 deletions
diff --git a/libquadmath/math/acoshq.c b/libquadmath/math/acoshq.c
new file mode 100644
index 000000000..b0a1e4e54
--- /dev/null
+++ b/libquadmath/math/acoshq.c
@@ -0,0 +1,59 @@
+/* e_acoshl.c -- long double version of e_acosh.c.
+ * Conversion to long double by Jakub Jelinek, jj@ultra.linux.cz.
+ */
+
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+/* __ieee754_acoshl(x)
+ * Method :
+ *	Based on
+ *		acoshl(x) = logl [ x + sqrtl(x*x-1) ]
+ *	we have
+ *		acoshl(x) := logl(x)+ln2,	if x is large; else
+ *		acoshl(x) := logl(2x-1/(sqrtl(x*x-1)+x)) if x>2; else
+ *		acoshl(x) := log1pl(t+sqrtl(2.0*t+t*t)); where t=x-1.
+ *
+ * Special cases:
+ *	acoshl(x) is NaN with signal if x<1.
+ *	acoshl(NaN) is NaN without signal.
+ */
+
+#include "quadmath-imp.h"
+
+static const __float128
+one	= 1.0Q,
+ln2	= 0.6931471805599453094172321214581766Q;
+
+__float128
+acoshq (__float128 x)
+{
+	__float128 t;
+	uint64_t lx;
+	int64_t hx;
+	GET_FLT128_WORDS64(hx,lx,x);
+	if(hx<0x3fff000000000000LL) {		/* x < 1 */
+	    return (x-x)/(x-x);
+	} else if(hx >=0x4035000000000000LL) {	/* x > 2**54 */
+	    if(hx >=0x7fff000000000000LL) {	/* x is inf of NaN */
+	        return x+x;
+	    } else
+		return logq(x)+ln2;	/* acoshl(huge)=logl(2x) */
+	} else if(((hx-0x3fff000000000000LL)|lx)==0) {
+	    return 0.0Q;			/* acosh(1) = 0 */
+	} else if (hx > 0x4000000000000000LL) {	/* 2**28 > x > 2 */
+	    t=x*x;
+	    return logq(2.0Q*x-one/(x+sqrtq(t-one)));
+	} else {			/* 1<x<2 */
+	    t = x-one;
+	    return log1pq(t+sqrtq(2.0Q*t+t*t));
+	}
+}