aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/libm-ieee754/s_sin.c
diff options
context:
space:
mode:
authorRoland McGrath <roland@gnu.org>1996-03-05 21:41:30 +0000
committerRoland McGrath <roland@gnu.org>1996-03-05 21:41:30 +0000
commitf7eac6eb504f4baf13dbb4d26717942df050ebe6 (patch)
tree95ff129c06c7f6f246a5e2bfa489ba6382659d19 /sysdeps/libm-ieee754/s_sin.c
parent1521668f2afae1dc2ef5d7ffaeb84353b36874dd (diff)
downloadglibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.tar
glibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.tar.gz
glibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.tar.bz2
glibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.zip
Mon Mar 4 20:54:40 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
* Makeconfig ($(common-objpfx)config.make): Depend on config.h.in. Mon Mar 4 17:35:09 1996 Roland McGrath <roland@charlie-brown.gnu.ai.mit.edu> * hurd/catch-signal.c (hurd_safe_memmove): New function. (hurd_safe_copyin, hurd_safe_copyout): New functions. * hurd/hurd/sigpreempt.h: Declare them. Sun Mar 3 08:43:44 1996 Roland McGrath <roland@charlie-brown.gnu.ai.mit.edu> Replace math code with fdlibm from Sun as modified for netbsd by JT Conklin and Ian Taylor, including x86 FPU support. * sysdeps/libm-ieee754, sysdeps/libm-i387: New directories. * math/math_private.h: New file. * sysdeps/i386/fpu/Implies: New file. * sysdeps/ieee754/Implies: New file. * math/machine/asm.h, math/machine/endian.h: New files. * math/Makefile, math/math.h: Rewritten. * mathcalls.h, math/mathcalls.h: New file, broken out of math.h. * math/finite.c: File removed. * sysdeps/generic/Makefile [$(subdir)=math]: Frobnication removed. * math/test-math.c: Include errno.h and string.h. * sysdeps/unix/bsd/dirstream.h: File removed. * sysdeps/unix/bsd/readdir.c: File removed.
Diffstat (limited to 'sysdeps/libm-ieee754/s_sin.c')
-rw-r--r--sysdeps/libm-ieee754/s_sin.c83
1 files changed, 83 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/s_sin.c b/sysdeps/libm-ieee754/s_sin.c
new file mode 100644
index 0000000000..efcf774158
--- /dev/null
+++ b/sysdeps/libm-ieee754/s_sin.c
@@ -0,0 +1,83 @@
+/* @(#)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]);
+ }
+ }
+}
+weak_alias (__sin, sin)