about summary refs log tree commit diff
path: root/sysdeps/libm-ieee754/k_tanf.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/k_tanf.c
parent1521668f2afae1dc2ef5d7ffaeb84353b36874dd (diff)
downloadglibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.tar.gz
glibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.tar.xz
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/k_tanf.c')
-rw-r--r--sysdeps/libm-ieee754/k_tanf.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/k_tanf.c b/sysdeps/libm-ieee754/k_tanf.c
new file mode 100644
index 0000000000..eb1a670939
--- /dev/null
+++ b/sysdeps/libm-ieee754/k_tanf.c
@@ -0,0 +1,101 @@
+/* k_tanf.c -- float version of k_tan.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.
+ * ====================================================
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: k_tanf.c,v 1.4 1995/05/10 20:46:39 jtc Exp $";
+#endif
+
+#include "math.h"
+#include "math_private.h"
+#ifdef __STDC__
+static const float 
+#else
+static float 
+#endif
+one   =  1.0000000000e+00, /* 0x3f800000 */
+pio4  =  7.8539812565e-01, /* 0x3f490fda */
+pio4lo=  3.7748947079e-08, /* 0x33222168 */
+T[] =  {
+  3.3333334327e-01, /* 0x3eaaaaab */
+  1.3333334029e-01, /* 0x3e088889 */
+  5.3968254477e-02, /* 0x3d5d0dd1 */
+  2.1869488060e-02, /* 0x3cb327a4 */
+  8.8632395491e-03, /* 0x3c11371f */
+  3.5920790397e-03, /* 0x3b6b6916 */
+  1.4562094584e-03, /* 0x3abede48 */
+  5.8804126456e-04, /* 0x3a1a26c8 */
+  2.4646313977e-04, /* 0x398137b9 */
+  7.8179444245e-05, /* 0x38a3f445 */
+  7.1407252108e-05, /* 0x3895c07a */
+ -1.8558637748e-05, /* 0xb79bae5f */
+  2.5907305826e-05, /* 0x37d95384 */
+};
+
+#ifdef __STDC__
+	float __kernel_tanf(float x, float y, int iy)
+#else
+	float __kernel_tanf(x, y, iy)
+	float x,y; int iy;
+#endif
+{
+	float z,r,v,w,s;
+	int32_t ix,hx;
+	GET_FLOAT_WORD(hx,x);
+	ix = hx&0x7fffffff;	/* high word of |x| */
+	if(ix<0x31800000)			/* x < 2**-28 */
+	    {if((int)x==0) {			/* generate inexact */
+		if((ix|(iy+1))==0) return one/fabsf(x);
+		else return (iy==1)? x: -one/x;
+	    }
+	    }
+	if(ix>=0x3f2ca140) { 			/* |x|>=0.6744 */
+	    if(hx<0) {x = -x; y = -y;}
+	    z = pio4-x;
+	    w = pio4lo-y;
+	    x = z+w; y = 0.0;
+	}
+	z	=  x*x;
+	w 	=  z*z;
+    /* Break x^5*(T[1]+x^2*T[2]+...) into
+     *	  x^5(T[1]+x^4*T[3]+...+x^20*T[11]) +
+     *	  x^5(x^2*(T[2]+x^4*T[4]+...+x^22*[T12]))
+     */
+	r = T[1]+w*(T[3]+w*(T[5]+w*(T[7]+w*(T[9]+w*T[11]))));
+	v = z*(T[2]+w*(T[4]+w*(T[6]+w*(T[8]+w*(T[10]+w*T[12])))));
+	s = z*x;
+	r = y + z*(s*(r+v)+y);
+	r += T[0]*s;
+	w = x+r;
+	if(ix>=0x3f2ca140) {
+	    v = (float)iy;
+	    return (float)(1-((hx>>30)&2))*(v-(float)2.0*(x-(w*w/(w+v)-r)));
+	}
+	if(iy==1) return w;
+	else {		/* if allow error up to 2 ulp, 
+			   simply return -1.0/(x+r) here */
+     /*  compute -1.0/(x+r) accurately */
+	    float a,t;
+	    int32_t i;
+	    z  = w;
+	    GET_FLOAT_WORD(i,z);
+	    SET_FLOAT_WORD(z,i&0xfffff000);
+	    v  = r-(z - x); 	/* z+v = r+x */
+	    t = a  = -(float)1.0/w;	/* a = -1.0/w */
+	    GET_FLOAT_WORD(i,t);
+	    SET_FLOAT_WORD(t,i&0xfffff000);
+	    s  = (float)1.0+t*z;
+	    return t+a*(s+t*v);
+	}
+}