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-rw-r--r--src/math/atanl.c91
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diff --git a/src/math/atanl.c b/src/math/atanl.c
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+/* origin: FreeBSD /usr/src/lib/msun/src/s_atanl.c */
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+/*
+ * See comments in atan.c.
+ * Converted to long double by David Schultz <das@FreeBSD.ORG>.
+ */
+
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double atanl(long double x)
+{
+ return atan(x);
+}
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+#include "__invtrigl.h"
+static const long double
+one = 1.0,
+huge = 1.0e300;
+
+long double atanl(long double x)
+{
+ union IEEEl2bits u;
+ long double w,s1,s2,z;
+ int id;
+ int16_t expsign, expt;
+ int32_t expman;
+
+ u.e = x;
+ expsign = u.xbits.expsign;
+ expt = expsign & 0x7fff;
+ if (expt >= ATAN_CONST) { /* if |x| is large, atan(x)~=pi/2 */
+ if (expt == BIAS + LDBL_MAX_EXP &&
+ ((u.bits.manh&~LDBL_NBIT)|u.bits.manl)!=0) /* NaN */
+ return x+x;
+ if (expsign > 0)
+ return atanhi[3]+atanlo[3];
+ else
+ return -atanhi[3]-atanlo[3];
+ }
+ /* Extract the exponent and the first few bits of the mantissa. */
+ /* XXX There should be a more convenient way to do this. */
+ expman = (expt << 8) | ((u.bits.manh >> (MANH_SIZE - 9)) & 0xff);
+ if (expman < ((BIAS - 2) << 8) + 0xc0) { /* |x| < 0.4375 */
+ if (expt < ATAN_LINEAR) { /* if |x| is small, atanl(x)~=x */
+ /* raise inexact */
+ if (huge+x > one)
+ return x;
+ }
+ id = -1;
+ } else {
+ x = fabsl(x);
+ if (expman < (BIAS << 8) + 0x30) { /* |x| < 1.1875 */
+ if (expman < ((BIAS - 1) << 8) + 0x60) { /* 7/16 <= |x| < 11/16 */
+ id = 0;
+ x = (2.0*x-one)/(2.0+x);
+ } else { /* 11/16 <= |x| < 19/16 */
+ id = 1;
+ x = (x-one)/(x+one);
+ }
+ } else {
+ if (expman < ((BIAS + 1) << 8) + 0x38) { /* |x| < 2.4375 */
+ id = 2;
+ x = (x-1.5)/(one+1.5*x);
+ } else { /* 2.4375 <= |x| < 2^ATAN_CONST */
+ id = 3;
+ x = -1.0/x;
+ }
+ }
+ }
+ /* end of argument reduction */
+ z = x*x;
+ w = z*z;
+ /* break sum aT[i]z**(i+1) into odd and even poly */
+ s1 = z*T_even(w);
+ s2 = w*T_odd(w);
+ if (id < 0)
+ return x - x*(s1+s2);
+ z = atanhi[id] - ((x*(s1+s2) - atanlo[id]) - x);
+ return expsign < 0 ? -z : z;
+}
+#endif