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-rw-r--r--src/math/e_acosf.c77
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diff --git a/src/math/e_acosf.c b/src/math/e_acosf.c
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+/* e_acosf.c -- float version of e_acos.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 */
+pi = 3.1415925026e+00, /* 0x40490fda */
+pio2_hi = 1.5707962513e+00, /* 0x3fc90fda */
+pio2_lo = 7.5497894159e-08, /* 0x33a22168 */
+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
+acosf(float x)
+{
+ float z,p,q,r,w,s,c,df;
+ int32_t hx,ix;
+ GET_FLOAT_WORD(hx,x);
+ ix = hx&0x7fffffff;
+ if(ix==0x3f800000) { /* |x|==1 */
+ if(hx>0) return 0.0; /* acos(1) = 0 */
+ else return pi+(float)2.0*pio2_lo; /* acos(-1)= pi */
+ } else if(ix>0x3f800000) { /* |x| >= 1 */
+ return (x-x)/(x-x); /* acos(|x|>1) is NaN */
+ }
+ if(ix<0x3f000000) { /* |x| < 0.5 */
+ if(ix<=0x23000000) return pio2_hi+pio2_lo;/*if|x|<2**-57*/
+ z = x*x;
+ p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
+ q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
+ r = p/q;
+ return pio2_hi - (x - (pio2_lo-x*r));
+ } else if (hx<0) { /* x < -0.5 */
+ z = (one+x)*(float)0.5;
+ p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
+ q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
+ s = sqrtf(z);
+ r = p/q;
+ w = r*s-pio2_lo;
+ return pi - (float)2.0*(s+w);
+ } else { /* x > 0.5 */
+ int32_t idf;
+ z = (one-x)*(float)0.5;
+ s = sqrtf(z);
+ df = s;
+ GET_FLOAT_WORD(idf,df);
+ SET_FLOAT_WORD(df,idf&0xfffff000);
+ c = (z-df*df)/(s+df);
+ p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
+ q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
+ r = p/q;
+ w = r*s+c;
+ return (float)2.0*(df+w);
+ }
+}