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diff --git a/sysdeps/ieee754/ldbl-128ibm/s_tanl.c b/sysdeps/ieee754/ldbl-128ibm/s_tanl.c
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+/* s_tanl.c -- long double version of s_tan.c.
+ * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
+ */
+
+/* @(#)s_tan.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+/* tanl(x)
+ * Return tangent function of x.
+ *
+ * kernel function:
+ * __kernel_tanl ... tangent function on [-pi/4,pi/4]
+ * __ieee754_rem_pio2l ... argument reduction routine
+ *
+ * Method.
+ * Let S,C and T denote the sin, cos and tan respectively on
+ * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
+ * in [-pi/4 , +pi/4], and let n = k mod 4.
+ * We have
+ *
+ * n sin(x) cos(x) tan(x)
+ * ----------------------------------------------------------
+ * 0 S C T
+ * 1 C -S -1/T
+ * 2 -S -C T
+ * 3 -C S -1/T
+ * ----------------------------------------------------------
+ *
+ * Special cases:
+ * Let trig be any of sin, cos, or tan.
+ * trig(+-INF) is NaN, with signals;
+ * trig(NaN) is that NaN;
+ *
+ * Accuracy:
+ * TRIG(x) returns trig(x) nearly rounded
+ */
+
+#include "math.h"
+#include "math_private.h"
+#include <math_ldbl_opt.h>
+
+#ifdef __STDC__
+ long double __tanl(long double x)
+#else
+ long double __tanl(x)
+ long double x;
+#endif
+{
+ long double y[2],z=0.0L;
+ int64_t n, ix;
+
+ /* High word of x. */
+ GET_LDOUBLE_MSW64(ix,x);
+
+ /* |x| ~< pi/4 */
+ ix &= 0x7fffffffffffffffLL;
+ if(ix <= 0x3fe921fb54442d10LL) return __kernel_tanl(x,z,1);
+
+ /* tanl(Inf or NaN) is NaN */
+ else if (ix>=0x7ff0000000000000LL) return x-x; /* NaN */
+
+ /* argument reduction needed */
+ else {
+ n = __ieee754_rem_pio2l(x,y);
+ return __kernel_tanl(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even
+ -1 -- n odd */
+ }
+}
+long_double_symbol (libm, __tanl, tanl);