J.T. Conklin's latest version of the Sun math library.

-- Begin comments from J.T. Conklin:
The most significant improvement is the addition of "float" versions
of the math functions that take float arguments, return floats, and do
all operations in floating point.  This doesn't help (performance)
much on the i386, but they are still nice to have.

The float versions were orginally done by Cygnus' Ian Taylor when
fdlibm was integrated into the libm we support for embedded systems.
I gave Ian a copy of my libm as a starting point since I had already
fixed a lot of bugs & problems in Sun's original code.  After he was
done, I cleaned it up a bit and integrated the changes back into my
libm.
-- End comments

Reviewed by:	jkh
Submitted by:	jtc

1 files changed, 158 insertions, 0 deletions

diff --git a/lib/msun/src/e_rem_pio2.c b/lib/msun/src/e_rem_pio2.c
new file mode 100644
index 0000000..bf8bfe1
--- /dev/null
+++ b/lib/msun/src/e_rem_pio2.c
@@ -0,0 +1,158 @@
+/* @(#)e_rem_pio2.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.
+ * ====================================================
+ */
+
+#ifndef lint
+static char rcsid[] = "$Id: e_rem_pio2.c,v 1.5 1994/08/18 23:05:56 jtc Exp $";
+#endif
+
+/* __ieee754_rem_pio2(x,y)
+ * 
+ * return the remainder of x rem pi/2 in y[0]+y[1] 
+ * use __kernel_rem_pio2()
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+/*
+ * Table of constants for 2/pi, 396 Hex digits (476 decimal) of 2/pi 
+ */
+#ifdef __STDC__
+static const int32_t two_over_pi[] = {
+#else
+static int32_t two_over_pi[] = {
+#endif
+0xA2F983, 0x6E4E44, 0x1529FC, 0x2757D1, 0xF534DD, 0xC0DB62, 
+0x95993C, 0x439041, 0xFE5163, 0xABDEBB, 0xC561B7, 0x246E3A, 
+0x424DD2, 0xE00649, 0x2EEA09, 0xD1921C, 0xFE1DEB, 0x1CB129, 
+0xA73EE8, 0x8235F5, 0x2EBB44, 0x84E99C, 0x7026B4, 0x5F7E41, 
+0x3991D6, 0x398353, 0x39F49C, 0x845F8B, 0xBDF928, 0x3B1FF8, 
+0x97FFDE, 0x05980F, 0xEF2F11, 0x8B5A0A, 0x6D1F6D, 0x367ECF, 
+0x27CB09, 0xB74F46, 0x3F669E, 0x5FEA2D, 0x7527BA, 0xC7EBE5, 
+0xF17B3D, 0x0739F7, 0x8A5292, 0xEA6BFB, 0x5FB11F, 0x8D5D08, 
+0x560330, 0x46FC7B, 0x6BABF0, 0xCFBC20, 0x9AF436, 0x1DA9E3, 
+0x91615E, 0xE61B08, 0x659985, 0x5F14A0, 0x68408D, 0xFFD880, 
+0x4D7327, 0x310606, 0x1556CA, 0x73A8C9, 0x60E27B, 0xC08C6B, 
+};
+
+#ifdef __STDC__
+static const int32_t npio2_hw[] = {
+#else
+static int32_t npio2_hw[] = {
+#endif
+0x3FF921FB, 0x400921FB, 0x4012D97C, 0x401921FB, 0x401F6A7A, 0x4022D97C,
+0x4025FDBB, 0x402921FB, 0x402C463A, 0x402F6A7A, 0x4031475C, 0x4032D97C,
+0x40346B9C, 0x4035FDBB, 0x40378FDB, 0x403921FB, 0x403AB41B, 0x403C463A,
+0x403DD85A, 0x403F6A7A, 0x40407E4C, 0x4041475C, 0x4042106C, 0x4042D97C,
+0x4043A28C, 0x40446B9C, 0x404534AC, 0x4045FDBB, 0x4046C6CB, 0x40478FDB,
+0x404858EB, 0x404921FB,
+};
+
+/*
+ * invpio2:  53 bits of 2/pi
+ * pio2_1:   first  33 bit of pi/2
+ * pio2_1t:  pi/2 - pio2_1
+ * pio2_2:   second 33 bit of pi/2
+ * pio2_2t:  pi/2 - (pio2_1+pio2_2)
+ * pio2_3:   third  33 bit of pi/2
+ * pio2_3t:  pi/2 - (pio2_1+pio2_2+pio2_3)
+ */
+
+#ifdef __STDC__
+static const double 
+#else
+static double 
+#endif
+zero =  0.00000000000000000000e+00, /* 0x00000000, 0x00000000 */
+half =  5.00000000000000000000e-01, /* 0x3FE00000, 0x00000000 */
+two24 =  1.67772160000000000000e+07, /* 0x41700000, 0x00000000 */
+invpio2 =  6.36619772367581382433e-01, /* 0x3FE45F30, 0x6DC9C883 */
+pio2_1  =  1.57079632673412561417e+00, /* 0x3FF921FB, 0x54400000 */
+pio2_1t =  6.07710050650619224932e-11, /* 0x3DD0B461, 0x1A626331 */
+pio2_2  =  6.07710050630396597660e-11, /* 0x3DD0B461, 0x1A600000 */
+pio2_2t =  2.02226624879595063154e-21, /* 0x3BA3198A, 0x2E037073 */
+pio2_3  =  2.02226624871116645580e-21, /* 0x3BA3198A, 0x2E000000 */
+pio2_3t =  8.47842766036889956997e-32; /* 0x397B839A, 0x252049C1 */
+
+#ifdef __STDC__
+	int32_t __ieee754_rem_pio2(double x, double *y)
+#else
+	int32_t __ieee754_rem_pio2(x,y)
+	double x,y[];
+#endif
+{
+	double z,w,t,r,fn;
+	double tx[3];
+	int32_t e0,i,j,nx,n,ix,hx;
+	u_int32_t low;
+
+	GET_HIGH_WORD(hx,x);		/* high word of x */
+	ix = hx&0x7fffffff;
+	if(ix<=0x3fe921fb)   /* |x| ~<= pi/4 , no need for reduction */
+	    {y[0] = x; y[1] = 0; return 0;}
+	if(ix<=0x413921fb) { /* |x| ~<= 2^19*(pi/2), medium size */
+	    t  = fabs(x);
+	    n  = (int32_t) (t*invpio2+half);
+	    fn = (double)n;
+	    r  = t-fn*pio2_1;
+	    w  = fn*pio2_1t;	/* 1st round good to 85 bit */
+	    if(n<32&&ix!=npio2_hw[n-1]) {	
+		y[0] = r-w;	/* quick check no cancellation */
+	    } else {
+	        u_int32_t high;
+	        j  = ix>>20;
+	        y[0] = r-w; 
+		GET_HIGH_WORD(high,y[0]);
+	        i = j-((high>>20)&0x7ff);
+	        if(i>16) {  /* 2nd iteration needed, good to 118 */
+		    t  = r;
+		    w  = fn*pio2_2;	
+		    r  = t-w;
+		    w  = fn*pio2_2t-((t-r)-w);	
+		    y[0] = r-w;
+		    GET_HIGH_WORD(high,y[0]);
+		    i = j-((high>>20)&0x7ff);
+		    if(i>49)  {	/* 3rd iteration need, 151 bits acc */
+		    	t  = r;	/* will cover all possible cases */
+		    	w  = fn*pio2_3;	
+		    	r  = t-w;
+		    	w  = fn*pio2_3t-((t-r)-w);	
+		    	y[0] = r-w;
+		    }
+		}
+	    }
+	    y[1] = (r-y[0])-w;
+	    if(hx<0) 	{y[0] = -y[0]; y[1] = -y[1]; return -n;}
+	    else	 return n;
+	}
+    /* 
+     * all other (large) arguments
+     */
+	if(ix>=0x7ff00000) {		/* x is inf or NaN */
+	    y[0]=y[1]=x-x; return 0;
+	}
+    /* set z = scalbn(|x|,ilogb(x)-23) */
+	GET_LOW_WORD(low,x);
+	SET_LOW_WORD(z,low);
+	e0 	= (ix>>20)-1046;	/* e0 = ilogb(z)-23; */
+	SET_HIGH_WORD(z, ix - ((int32_t)(e0<<20)));
+	for(i=0;i<2;i++) {
+		tx[i] = (double)((int32_t)(z));
+		z     = (z-tx[i])*two24;
+	}
+	tx[2] = z;
+	nx = 3;
+	while(tx[nx-1]==zero) nx--;	/* skip zero term */
+	n  =  __kernel_rem_pio2(tx,y,e0,nx,2,two_over_pi);
+	if(hx<0) {y[0] = -y[0]; y[1] = -y[1]; return -n;}
+	return n;
+}