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, 253 insertions, 0 deletions

diff --git a/lib/msun/src/e_powf.c b/lib/msun/src/e_powf.c
new file mode 100644
index 0000000..2d1ef4a
--- /dev/null
+++ b/lib/msun/src/e_powf.c
@@ -0,0 +1,253 @@
+/* e_powf.c -- float version of e_pow.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.
+ * ====================================================
+ */
+
+#ifndef lint
+static char rcsid[] = "$Id: e_powf.c,v 1.2 1994/08/18 23:05:54 jtc Exp $";
+#endif
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const float
+#else
+static float
+#endif
+bp[] = {1.0, 1.5,},
+dp_h[] = { 0.0, 5.84960938e-01,}, /* 0x3f15c000 */
+dp_l[] = { 0.0, 1.56322085e-06,}, /* 0x35d1cfdc */
+zero    =  0.0,
+one	=  1.0,
+two	=  2.0,
+two24	=  16777216.0,	/* 0x4b800000 */
+huge	=  1.0e30,
+tiny    =  1.0e-30,
+	/* poly coefs for (3/2)*(log(x)-2s-2/3*s**3 */
+L1  =  6.0000002384e-01, /* 0x3f19999a */
+L2  =  4.2857143283e-01, /* 0x3edb6db7 */
+L3  =  3.3333334327e-01, /* 0x3eaaaaab */
+L4  =  2.7272811532e-01, /* 0x3e8ba305 */
+L5  =  2.3066075146e-01, /* 0x3e6c3255 */
+L6  =  2.0697501302e-01, /* 0x3e53f142 */
+P1   =  1.6666667163e-01, /* 0x3e2aaaab */
+P2   = -2.7777778450e-03, /* 0xbb360b61 */
+P3   =  6.6137559770e-05, /* 0x388ab355 */
+P4   = -1.6533901999e-06, /* 0xb5ddea0e */
+P5   =  4.1381369442e-08, /* 0x3331bb4c */
+lg2  =  6.9314718246e-01, /* 0x3f317218 */
+lg2_h  =  6.93145752e-01, /* 0x3f317200 */
+lg2_l  =  1.42860654e-06, /* 0x35bfbe8c */
+ovt =  4.2995665694e-08, /* -(128-log2(ovfl+.5ulp)) */
+cp    =  9.6179670095e-01, /* 0x3f76384f =2/(3ln2) */
+cp_h  =  9.6179199219e-01, /* 0x3f763800 =head of cp */
+cp_l  =  4.7017383622e-06, /* 0x369dc3a0 =tail of cp_h */
+ivln2    =  1.4426950216e+00, /* 0x3fb8aa3b =1/ln2 */
+ivln2_h  =  1.4426879883e+00, /* 0x3fb8aa00 =16b 1/ln2*/
+ivln2_l  =  7.0526075433e-06; /* 0x36eca570 =1/ln2 tail*/
+
+#ifdef __STDC__
+	float __ieee754_powf(float x, float y)
+#else
+	float __ieee754_powf(x,y)
+	float x, y;
+#endif
+{
+	float z,ax,z_h,z_l,p_h,p_l;
+	float y1,t1,t2,r,s,t,u,v,w;
+	int32_t i,j,k,yisint,n;
+	int32_t hx,hy,ix,iy,is;
+
+	GET_FLOAT_WORD(hx,x);
+	GET_FLOAT_WORD(hy,y);
+	ix = hx&0x7fffffff;  iy = hy&0x7fffffff;
+
+    /* y==zero: x**0 = 1 */
+	if(iy==0) return one; 	
+
+    /* +-NaN return x+y */
+	if(ix > 0x7f800000 ||
+	   iy > 0x7f800000)
+		return x+y;	
+
+    /* determine if y is an odd int when x < 0
+     * yisint = 0	... y is not an integer
+     * yisint = 1	... y is an odd int
+     * yisint = 2	... y is an even int
+     */
+	yisint  = 0;
+	if(hx<0) {	
+	    if(iy>=0x4b800000) yisint = 2; /* even integer y */
+	    else if(iy>=0x3f800000) {
+		k = (iy>>23)-0x7f;	   /* exponent */
+		j = iy>>(23-k);
+		if((j<<(23-k))==iy) yisint = 2-(j&1);
+	    }		
+	} 
+
+    /* special value of y */
+	if (iy==0x7f800000) {	/* y is +-inf */
+	    if (ix==0x3f800000)
+	        return  y - y;	/* inf**+-1 is NaN */
+	    else if (ix > 0x3f800000)/* (|x|>1)**+-inf = inf,0 */
+	        return (hy>=0)? y: zero;
+	    else			/* (|x|<1)**-,+inf = inf,0 */
+	        return (hy<0)?-y: zero;
+	} 
+	if(iy==0x3f800000) {	/* y is  +-1 */
+	    if(hy<0) return one/x; else return x;
+	}
+	if(hy==0x40000000) return x*x; /* y is  2 */
+	if(hy==0x3f000000) {	/* y is  0.5 */
+	    if(hx>=0)	/* x >= +0 */
+	    return sqrtf(x);	
+	}
+
+	ax   = fabsf(x);
+    /* special value of x */
+	if(ix==0x7f800000||ix==0||ix==0x3f800000){
+	    z = ax;			/*x is +-0,+-inf,+-1*/
+	    if(hy<0) z = one/z;	/* z = (1/|x|) */
+	    if(hx<0) {
+		if(((ix-0x3f800000)|yisint)==0) {
+		    z = (z-z)/(z-z); /* (-1)**non-int is NaN */
+		} else if(yisint==1) 
+		    z = -z;		/* (x<0)**odd = -(|x|**odd) */
+	    }
+	    return z;
+	}
+    
+    /* (x<0)**(non-int) is NaN */
+	if(((((u_int32_t)hx>>31)-1)|yisint)==0) return (x-x)/(x-x);
+
+    /* |y| is huge */
+	if(iy>0x4d000000) { /* if |y| > 2**27 */
+	/* over/underflow if x is not close to one */
+	    if(ix<0x3f7ffff8) return (hy<0)? huge*huge:tiny*tiny;
+	    if(ix>0x3f800007) return (hy>0)? huge*huge:tiny*tiny;
+	/* now |1-x| is tiny <= 2**-20, suffice to compute 
+	   log(x) by x-x^2/2+x^3/3-x^4/4 */
+	    t = x-1;		/* t has 20 trailing zeros */
+	    w = (t*t)*((float)0.5-t*((float)0.333333333333-t*(float)0.25));
+	    u = ivln2_h*t;	/* ivln2_h has 16 sig. bits */
+	    v = t*ivln2_l-w*ivln2;
+	    t1 = u+v;
+	    GET_FLOAT_WORD(is,t1);
+	    SET_FLOAT_WORD(t1,is&0xfffff000);
+	    t2 = v-(t1-u);
+	} else {
+	    float s2,s_h,s_l,t_h,t_l;
+	    n = 0;
+	/* take care subnormal number */
+	    if(ix<0x00800000)
+		{ax *= two24; n -= 24; GET_FLOAT_WORD(ix,ax); }
+	    n  += ((ix)>>23)-0x7f;
+	    j  = ix&0x007fffff;
+	/* determine interval */
+	    ix = j|0x3f800000;		/* normalize ix */
+	    if(j<=0x1cc471) k=0;	/* |x|<sqrt(3/2) */
+	    else if(j<0x5db3d7) k=1;	/* |x|<sqrt(3)   */
+	    else {k=0;n+=1;ix -= 0x00800000;}
+	    SET_FLOAT_WORD(ax,ix);
+
+	/* compute s = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */
+	    u = ax-bp[k];		/* bp[0]=1.0, bp[1]=1.5 */
+	    v = one/(ax+bp[k]);
+	    s = u*v;
+	    s_h = s;
+	    GET_FLOAT_WORD(is,s_h);
+	    SET_FLOAT_WORD(s_h,is&0xfffff000);
+	/* t_h=ax+bp[k] High */
+	    SET_FLOAT_WORD(t_h,((ix>>1)|0x20000000)+0x0040000+(k<<21));
+	    t_l = ax - (t_h-bp[k]);
+	    s_l = v*((u-s_h*t_h)-s_h*t_l);
+	/* compute log(ax) */
+	    s2 = s*s;
+	    r = s2*s2*(L1+s2*(L2+s2*(L3+s2*(L4+s2*(L5+s2*L6)))));
+	    r += s_l*(s_h+s);
+	    s2  = s_h*s_h;
+	    t_h = (float)3.0+s2+r;
+	    GET_FLOAT_WORD(is,t_h);
+	    SET_FLOAT_WORD(t_h,is&0xfffff000);
+	    t_l = r-((t_h-(float)3.0)-s2);
+	/* u+v = s*(1+...) */
+	    u = s_h*t_h;
+	    v = s_l*t_h+t_l*s;
+	/* 2/(3log2)*(s+...) */
+	    p_h = u+v;
+	    GET_FLOAT_WORD(is,p_h);
+	    SET_FLOAT_WORD(p_h,is&0xfffff000);
+	    p_l = v-(p_h-u);
+	    z_h = cp_h*p_h;		/* cp_h+cp_l = 2/(3*log2) */
+	    z_l = cp_l*p_h+p_l*cp+dp_l[k];
+	/* log2(ax) = (s+..)*2/(3*log2) = n + dp_h + z_h + z_l */
+	    t = (float)n;
+	    t1 = (((z_h+z_l)+dp_h[k])+t);
+	    GET_FLOAT_WORD(is,t1);
+	    SET_FLOAT_WORD(t1,is&0xfffff000);
+	    t2 = z_l-(((t1-t)-dp_h[k])-z_h);
+	}
+
+	s = one; /* s (sign of result -ve**odd) = -1 else = 1 */
+	if(((((u_int32_t)hx>>31)-1)|(yisint-1))==0)
+	    s = -one;	/* (-ve)**(odd int) */
+
+    /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */
+	GET_FLOAT_WORD(is,y);
+	SET_FLOAT_WORD(y1,is&0xfffff000);
+	p_l = (y-y1)*t1+y*t2;
+	p_h = y1*t1;
+	z = p_l+p_h;
+	GET_FLOAT_WORD(j,z);
+	if (j>0x43000000)				/* if z > 128 */
+	    return s*huge*huge;				/* overflow */
+	else if (j==0x43000000) {			/* if z == 128 */
+	    if(p_l+ovt>z-p_h) return s*huge*huge;	/* overflow */
+	}
+	else if ((j&0x7fffffff)>0x43160000)		/* z <= -150 */
+	    return s*tiny*tiny;				/* underflow */
+	else if (j==0xc3160000){			/* z == -150 */
+	    if(p_l<=z-p_h) return s*tiny*tiny;		/* underflow */
+	}
+    /*
+     * compute 2**(p_h+p_l)
+     */
+	i = j&0x7fffffff;
+	k = (i>>23)-0x7f;
+	n = 0;
+	if(i>0x3f000000) {		/* if |z| > 0.5, set n = [z+0.5] */
+	    n = j+(0x00800000>>(k+1));
+	    k = ((n&0x7fffffff)>>23)-0x7f;	/* new k for n */
+	    SET_FLOAT_WORD(t,n&~(0x007fffff>>k));
+	    n = ((n&0x007fffff)|0x00800000)>>(23-k);
+	    if(j<0) n = -n;
+	    p_h -= t;
+	} 
+	t = p_l+p_h;
+	GET_FLOAT_WORD(is,t);
+	SET_FLOAT_WORD(t,is&0xfffff000);
+	u = t*lg2_h;
+	v = (p_l-(t-p_h))*lg2+t*lg2_l;
+	z = u+v;
+	w = v-(z-u);
+	t  = z*z;
+	t1  = z - t*(P1+t*(P2+t*(P3+t*(P4+t*P5))));
+	r  = (z*t1)/(t1-two)-(w+z*w);
+	z  = one-(r-z);
+	GET_FLOAT_WORD(j,z);
+	j += (n<<23);
+	if((j>>23)<=0) z = scalbnf(z,n);	/* subnormal output */
+	else SET_FLOAT_WORD(z,j);
+	return s*z;
+}