initial import

[picodrive.git] / platform / gp2x / uClibc / s_sin.c

diff --git a/platform/gp2x/uClibc/s_sin.c b/platform/gp2x/uClibc/s_sin.c
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+++ b/platform/gp2x/uClibc/s_sin.c
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+/* @(#)s_sin.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.
+ * ====================================================
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: s_sin.c,v 1.7 1995/05/10 20:48:15 jtc Exp $";
+#endif
+
+/* sin(x)
+ * Return sine function of x.
+ *
+ * kernel function:
+ *     __kernel_sin            ... sine function on [-pi/4,pi/4]
+ *     __kernel_cos            ... cose function on [-pi/4,pi/4]
+ *     __ieee754_rem_pio2      ... 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"
+
+#ifdef __STDC__
+       double sin(double x)
+#else
+       double sin(x)
+       double x;
+#endif
+{
+       double y[2],z=0.0;
+       int32_t n, ix;
+
+    /* High word of x. */
+       GET_HIGH_WORD(ix,x);
+
+    /* |x| ~< pi/4 */
+       ix &= 0x7fffffff;
+       if(ix <= 0x3fe921fb) return __kernel_sin(x,z,0);
+
+    /* sin(Inf or NaN) is NaN */
+       else if (ix>=0x7ff00000) return x-x;
+
+    /* argument reduction needed */
+       else {
+           n = __ieee754_rem_pio2(x,y);
+           switch(n&3) {
+               case 0: return  __kernel_sin(y[0],y[1],1);
+               case 1: return  __kernel_cos(y[0],y[1]);
+               case 2: return -__kernel_sin(y[0],y[1],1);
+               default:
+                       return -__kernel_cos(y[0],y[1]);
+           }
+       }
+}