From 0b44a0315b47dd8eced9f3b7f31580cf14bbfc01 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Sat, 12 Feb 2011 00:22:29 -0500
Subject: initial check-in, version 0.5.0

---
 src/math/e_asinf.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 src/math/e_asinf.c

(limited to 'src/math/e_asinf.c')

diff --git a/src/math/e_asinf.c b/src/math/e_asinf.c
new file mode 100644
index 00000000..9c693970
--- /dev/null
+++ b/src/math/e_asinf.c
@@ -0,0 +1,80 @@
+/* e_asinf.c -- float version of e_asin.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 <math.h>
+#include "math_private.h"
+
+static const float
+one =  1.0000000000e+00, /* 0x3F800000 */
+huge =  1.000e+30,
+pio2_hi =  1.5707962513e+00, /* 0x3fc90fda */
+pio2_lo =  7.5497894159e-08, /* 0x33a22168 */
+pio4_hi =  7.8539818525e-01, /* 0x3f490fdb */
+	/* coefficient for R(x^2) */
+pS0 =  1.6666667163e-01, /* 0x3e2aaaab */
+pS1 = -3.2556581497e-01, /* 0xbea6b090 */
+pS2 =  2.0121252537e-01, /* 0x3e4e0aa8 */
+pS3 = -4.0055535734e-02, /* 0xbd241146 */
+pS4 =  7.9153501429e-04, /* 0x3a4f7f04 */
+pS5 =  3.4793309169e-05, /* 0x3811ef08 */
+qS1 = -2.4033949375e+00, /* 0xc019d139 */
+qS2 =  2.0209457874e+00, /* 0x4001572d */
+qS3 = -6.8828397989e-01, /* 0xbf303361 */
+qS4 =  7.7038154006e-02; /* 0x3d9dc62e */
+
+float
+asinf(float x)
+{
+	float t=0.0,w,p,q,c,r,s;
+	int32_t hx,ix;
+	GET_FLOAT_WORD(hx,x);
+	ix = hx&0x7fffffff;
+	if(ix==0x3f800000) {
+		/* asin(1)=+-pi/2 with inexact */
+	    return x*pio2_hi+x*pio2_lo;
+	} else if(ix> 0x3f800000) {	/* |x|>= 1 */
+	    return (x-x)/(x-x);		/* asin(|x|>1) is NaN */
+	} else if (ix<0x3f000000) {	/* |x|<0.5 */
+	    if(ix<0x32000000) {		/* if |x| < 2**-27 */
+		if(huge+x>one) return x;/* return x with inexact if x!=0*/
+	    } else
+		t = x*x;
+		p = t*(pS0+t*(pS1+t*(pS2+t*(pS3+t*(pS4+t*pS5)))));
+		q = one+t*(qS1+t*(qS2+t*(qS3+t*qS4)));
+		w = p/q;
+		return x+x*w;
+	}
+	/* 1> |x|>= 0.5 */
+	w = one-fabsf(x);
+	t = w*(float)0.5;
+	p = t*(pS0+t*(pS1+t*(pS2+t*(pS3+t*(pS4+t*pS5)))));
+	q = one+t*(qS1+t*(qS2+t*(qS3+t*qS4)));
+	s = sqrtf(t);
+	if(ix>=0x3F79999A) { 	/* if |x| > 0.975 */
+	    w = p/q;
+	    t = pio2_hi-((float)2.0*(s+s*w)-pio2_lo);
+	} else {
+	    int32_t iw;
+	    w  = s;
+	    GET_FLOAT_WORD(iw,w);
+	    SET_FLOAT_WORD(w,iw&0xfffff000);
+	    c  = (t-w*w)/(s+w);
+	    r  = p/q;
+	    p  = (float)2.0*s*r-(pio2_lo-(float)2.0*c);
+	    q  = pio4_hi-(float)2.0*w;
+	    t  = pio4_hi-(p-q);
+	}
+	if(hx>0) return t; else return -t;
+}
-- 
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