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-rw-r--r--modules/fdlibm/src/e_asinf.cpp66
1 files changed, 66 insertions, 0 deletions
diff --git a/modules/fdlibm/src/e_asinf.cpp b/modules/fdlibm/src/e_asinf.cpp
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+++ b/modules/fdlibm/src/e_asinf.cpp
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+/* 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 <sys/cdefs.h>
+//__FBSDID("$FreeBSD$");
+
+#include <cmath>
+
+#include "math_private.h"
+
+static const float
+one = 1.0000000000e+00, /* 0x3F800000 */
+huge = 1.000e+30,
+ /* coefficient for R(x^2) */
+pS0 = 1.6666586697e-01,
+pS1 = -4.2743422091e-02,
+pS2 = -8.6563630030e-03,
+qS1 = -7.0662963390e-01;
+
+static const double
+pio2 = 1.570796326794896558e+00;
+
+float
+__ieee754_asinf(float x)
+{
+ double s;
+ float t,w,p,q;
+ int32_t hx,ix;
+ GET_FLOAT_WORD(hx,x);
+ ix = hx&0x7fffffff;
+ if(ix>=0x3f800000) { /* |x| >= 1 */
+ if(ix==0x3f800000) /* |x| == 1 */
+ return x*pio2; /* asin(+-1) = +-pi/2 with inexact */
+ return (x-x)/(x-x); /* asin(|x|>1) is NaN */
+ } else if (ix<0x3f000000) { /* |x|<0.5 */
+ if(ix<0x39800000) { /* |x| < 2**-12 */
+ if(huge+x>one) return x;/* return x with inexact if x!=0*/
+ }
+ t = x*x;
+ p = t*(pS0+t*(pS1+t*pS2));
+ q = one+t*qS1;
+ 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));
+ q = one+t*qS1;
+ s = std::sqrt(t);
+ w = p/q;
+ t = pio2-2.0*(s+s*w);
+ if(hx>0) return t; else return -t;
+}