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-rw-r--r--lib/mlibc/options/ansi/musl-generic-math/asinf.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/lib/mlibc/options/ansi/musl-generic-math/asinf.c b/lib/mlibc/options/ansi/musl-generic-math/asinf.c
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index 0000000..bcd304a
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+++ b/lib/mlibc/options/ansi/musl-generic-math/asinf.c
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+/* origin: FreeBSD /usr/src/lib/msun/src/e_asinf.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 "libm.h"
+
+static const double
+pio2 = 1.570796326794896558e+00;
+
+static const float
+/* coefficients for R(x^2) */
+pS0 = 1.6666586697e-01,
+pS1 = -4.2743422091e-02,
+pS2 = -8.6563630030e-03,
+qS1 = -7.0662963390e-01;
+
+static float R(float z)
+{
+ float_t p, q;
+ p = z*(pS0+z*(pS1+z*pS2));
+ q = 1.0f+z*qS1;
+ return p/q;
+}
+
+float asinf(float x)
+{
+ double s;
+ float z;
+ uint32_t hx,ix;
+
+ GET_FLOAT_WORD(hx, x);
+ ix = hx & 0x7fffffff;
+ if (ix >= 0x3f800000) { /* |x| >= 1 */
+ if (ix == 0x3f800000) /* |x| == 1 */
+ return x*pio2 + 0x1p-120f; /* asin(+-1) = +-pi/2 with inexact */
+ return 0/(x-x); /* asin(|x|>1) is NaN */
+ }
+ if (ix < 0x3f000000) { /* |x| < 0.5 */
+ /* if 0x1p-126 <= |x| < 0x1p-12, avoid raising underflow */
+ if (ix < 0x39800000 && ix >= 0x00800000)
+ return x;
+ return x + x*R(x*x);
+ }
+ /* 1 > |x| >= 0.5 */
+ z = (1 - fabsf(x))*0.5f;
+ s = sqrt(z);
+ x = pio2 - 2*(s+s*R(z));
+ if (hx >> 31)
+ return -x;
+ return x;
+}