Upgrade libm.
This brings us up to date with FreeBSD HEAD, fixes various bugs, unifies
the set of functions we support on ARM, MIPS, and x86, fixes "long double",
adds ISO C99 support, and adds basic unit tests.
It turns out that our "long double" functions have always been broken
for non-normal numbers. This patch fixes that by not using the upstream
implementations and just forwarding to the regular "double" implementation
instead (since "long double" on Android is just "double" anyway, which is
what BSD doesn't support).
All the tests pass on ARM, MIPS, and x86, plus glibc on x86-64.
Bug: 3169850
Bug: 8012787
Bug: https://code.google.com/p/android/issues/detail?id=6697
Change-Id: If0c343030959c24bfc50d4d21c9530052c581837
diff --git a/libm/upstream-freebsd/lib/msun/src/e_pow.c b/libm/upstream-freebsd/lib/msun/src/e_pow.c
new file mode 100644
index 0000000..7607a4a
--- /dev/null
+++ b/libm/upstream-freebsd/lib/msun/src/e_pow.c
@@ -0,0 +1,306 @@
+/* @(#)e_pow.c 1.5 04/04/22 SMI */
+/*
+ * ====================================================
+ * Copyright (C) 2004 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+/* __ieee754_pow(x,y) return x**y
+ *
+ * n
+ * Method: Let x = 2 * (1+f)
+ * 1. Compute and return log2(x) in two pieces:
+ * log2(x) = w1 + w2,
+ * where w1 has 53-24 = 29 bit trailing zeros.
+ * 2. Perform y*log2(x) = n+y' by simulating muti-precision
+ * arithmetic, where |y'|<=0.5.
+ * 3. Return x**y = 2**n*exp(y'*log2)
+ *
+ * Special cases:
+ * 1. (anything) ** 0 is 1
+ * 2. (anything) ** 1 is itself
+ * 3. (anything) ** NAN is NAN
+ * 4. NAN ** (anything except 0) is NAN
+ * 5. +-(|x| > 1) ** +INF is +INF
+ * 6. +-(|x| > 1) ** -INF is +0
+ * 7. +-(|x| < 1) ** +INF is +0
+ * 8. +-(|x| < 1) ** -INF is +INF
+ * 9. +-1 ** +-INF is NAN
+ * 10. +0 ** (+anything except 0, NAN) is +0
+ * 11. -0 ** (+anything except 0, NAN, odd integer) is +0
+ * 12. +0 ** (-anything except 0, NAN) is +INF
+ * 13. -0 ** (-anything except 0, NAN, odd integer) is +INF
+ * 14. -0 ** (odd integer) = -( +0 ** (odd integer) )
+ * 15. +INF ** (+anything except 0,NAN) is +INF
+ * 16. +INF ** (-anything except 0,NAN) is +0
+ * 17. -INF ** (anything) = -0 ** (-anything)
+ * 18. (-anything) ** (integer) is (-1)**(integer)*(+anything**integer)
+ * 19. (-anything except 0 and inf) ** (non-integer) is NAN
+ *
+ * Accuracy:
+ * pow(x,y) returns x**y nearly rounded. In particular
+ * pow(integer,integer)
+ * always returns the correct integer provided it is
+ * representable.
+ *
+ * Constants :
+ * The hexadecimal values are the intended ones for the following
+ * constants. The decimal values may be used, provided that the
+ * compiler will convert from decimal to binary accurately enough
+ * to produce the hexadecimal values shown.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+static const double
+bp[] = {1.0, 1.5,},
+dp_h[] = { 0.0, 5.84962487220764160156e-01,}, /* 0x3FE2B803, 0x40000000 */
+dp_l[] = { 0.0, 1.35003920212974897128e-08,}, /* 0x3E4CFDEB, 0x43CFD006 */
+zero = 0.0,
+one = 1.0,
+two = 2.0,
+two53 = 9007199254740992.0, /* 0x43400000, 0x00000000 */
+huge = 1.0e300,
+tiny = 1.0e-300,
+ /* poly coefs for (3/2)*(log(x)-2s-2/3*s**3 */
+L1 = 5.99999999999994648725e-01, /* 0x3FE33333, 0x33333303 */
+L2 = 4.28571428578550184252e-01, /* 0x3FDB6DB6, 0xDB6FABFF */
+L3 = 3.33333329818377432918e-01, /* 0x3FD55555, 0x518F264D */
+L4 = 2.72728123808534006489e-01, /* 0x3FD17460, 0xA91D4101 */
+L5 = 2.30660745775561754067e-01, /* 0x3FCD864A, 0x93C9DB65 */
+L6 = 2.06975017800338417784e-01, /* 0x3FCA7E28, 0x4A454EEF */
+P1 = 1.66666666666666019037e-01, /* 0x3FC55555, 0x5555553E */
+P2 = -2.77777777770155933842e-03, /* 0xBF66C16C, 0x16BEBD93 */
+P3 = 6.61375632143793436117e-05, /* 0x3F11566A, 0xAF25DE2C */
+P4 = -1.65339022054652515390e-06, /* 0xBEBBBD41, 0xC5D26BF1 */
+P5 = 4.13813679705723846039e-08, /* 0x3E663769, 0x72BEA4D0 */
+lg2 = 6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */
+lg2_h = 6.93147182464599609375e-01, /* 0x3FE62E43, 0x00000000 */
+lg2_l = -1.90465429995776804525e-09, /* 0xBE205C61, 0x0CA86C39 */
+ovt = 8.0085662595372944372e-0017, /* -(1024-log2(ovfl+.5ulp)) */
+cp = 9.61796693925975554329e-01, /* 0x3FEEC709, 0xDC3A03FD =2/(3ln2) */
+cp_h = 9.61796700954437255859e-01, /* 0x3FEEC709, 0xE0000000 =(float)cp */
+cp_l = -7.02846165095275826516e-09, /* 0xBE3E2FE0, 0x145B01F5 =tail of cp_h*/
+ivln2 = 1.44269504088896338700e+00, /* 0x3FF71547, 0x652B82FE =1/ln2 */
+ivln2_h = 1.44269502162933349609e+00, /* 0x3FF71547, 0x60000000 =24b 1/ln2*/
+ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/
+
+double
+__ieee754_pow(double x, double y)
+{
+ double z,ax,z_h,z_l,p_h,p_l;
+ double y1,t1,t2,r,s,t,u,v,w;
+ int32_t i,j,k,yisint,n;
+ int32_t hx,hy,ix,iy;
+ u_int32_t lx,ly;
+
+ EXTRACT_WORDS(hx,lx,x);
+ EXTRACT_WORDS(hy,ly,y);
+ ix = hx&0x7fffffff; iy = hy&0x7fffffff;
+
+ /* y==zero: x**0 = 1 */
+ if((iy|ly)==0) return one;
+
+ /* x==1: 1**y = 1, even if y is NaN */
+ if (hx==0x3ff00000 && lx == 0) return one;
+
+ /* y!=zero: result is NaN if either arg is NaN */
+ if(ix > 0x7ff00000 || ((ix==0x7ff00000)&&(lx!=0)) ||
+ iy > 0x7ff00000 || ((iy==0x7ff00000)&&(ly!=0)))
+ return (x+0.0)+(y+0.0);
+
+ /* 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>=0x43400000) yisint = 2; /* even integer y */
+ else if(iy>=0x3ff00000) {
+ k = (iy>>20)-0x3ff; /* exponent */
+ if(k>20) {
+ j = ly>>(52-k);
+ if((j<<(52-k))==ly) yisint = 2-(j&1);
+ } else if(ly==0) {
+ j = iy>>(20-k);
+ if((j<<(20-k))==iy) yisint = 2-(j&1);
+ }
+ }
+ }
+
+ /* special value of y */
+ if(ly==0) {
+ if (iy==0x7ff00000) { /* y is +-inf */
+ if(((ix-0x3ff00000)|lx)==0)
+ return one; /* (-1)**+-inf is NaN */
+ else if (ix >= 0x3ff00000)/* (|x|>1)**+-inf = inf,0 */
+ return (hy>=0)? y: zero;
+ else /* (|x|<1)**-,+inf = inf,0 */
+ return (hy<0)?-y: zero;
+ }
+ if(iy==0x3ff00000) { /* y is +-1 */
+ if(hy<0) return one/x; else return x;
+ }
+ if(hy==0x40000000) return x*x; /* y is 2 */
+ if(hy==0x3fe00000) { /* y is 0.5 */
+ if(hx>=0) /* x >= +0 */
+ return sqrt(x);
+ }
+ }
+
+ ax = fabs(x);
+ /* special value of x */
+ if(lx==0) {
+ if(ix==0x7ff00000||ix==0||ix==0x3ff00000){
+ z = ax; /*x is +-0,+-inf,+-1*/
+ if(hy<0) z = one/z; /* z = (1/|x|) */
+ if(hx<0) {
+ if(((ix-0x3ff00000)|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;
+ }
+ }
+
+ /* CYGNUS LOCAL + fdlibm-5.3 fix: This used to be
+ n = (hx>>31)+1;
+ but ANSI C says a right shift of a signed negative quantity is
+ implementation defined. */
+ n = ((u_int32_t)hx>>31)-1;
+
+ /* (x<0)**(non-int) is NaN */
+ if((n|yisint)==0) return (x-x)/(x-x);
+
+ s = one; /* s (sign of result -ve**odd) = -1 else = 1 */
+ if((n|(yisint-1))==0) s = -one;/* (-ve)**(odd int) */
+
+ /* |y| is huge */
+ if(iy>0x41e00000) { /* if |y| > 2**31 */
+ if(iy>0x43f00000){ /* if |y| > 2**64, must o/uflow */
+ if(ix<=0x3fefffff) return (hy<0)? huge*huge:tiny*tiny;
+ if(ix>=0x3ff00000) return (hy>0)? huge*huge:tiny*tiny;
+ }
+ /* over/underflow if x is not close to one */
+ if(ix<0x3fefffff) return (hy<0)? s*huge*huge:s*tiny*tiny;
+ if(ix>0x3ff00000) return (hy>0)? s*huge*huge:s*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 = ax-one; /* t has 20 trailing zeros */
+ w = (t*t)*(0.5-t*(0.3333333333333333333333-t*0.25));
+ u = ivln2_h*t; /* ivln2_h has 21 sig. bits */
+ v = t*ivln2_l-w*ivln2;
+ t1 = u+v;
+ SET_LOW_WORD(t1,0);
+ t2 = v-(t1-u);
+ } else {
+ double ss,s2,s_h,s_l,t_h,t_l;
+ n = 0;
+ /* take care subnormal number */
+ if(ix<0x00100000)
+ {ax *= two53; n -= 53; GET_HIGH_WORD(ix,ax); }
+ n += ((ix)>>20)-0x3ff;
+ j = ix&0x000fffff;
+ /* determine interval */
+ ix = j|0x3ff00000; /* normalize ix */
+ if(j<=0x3988E) k=0; /* |x|<sqrt(3/2) */
+ else if(j<0xBB67A) k=1; /* |x|<sqrt(3) */
+ else {k=0;n+=1;ix -= 0x00100000;}
+ SET_HIGH_WORD(ax,ix);
+
+ /* compute ss = 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]);
+ ss = u*v;
+ s_h = ss;
+ SET_LOW_WORD(s_h,0);
+ /* t_h=ax+bp[k] High */
+ t_h = zero;
+ SET_HIGH_WORD(t_h,((ix>>1)|0x20000000)+0x00080000+(k<<18));
+ t_l = ax - (t_h-bp[k]);
+ s_l = v*((u-s_h*t_h)-s_h*t_l);
+ /* compute log(ax) */
+ s2 = ss*ss;
+ r = s2*s2*(L1+s2*(L2+s2*(L3+s2*(L4+s2*(L5+s2*L6)))));
+ r += s_l*(s_h+ss);
+ s2 = s_h*s_h;
+ t_h = 3.0+s2+r;
+ SET_LOW_WORD(t_h,0);
+ t_l = r-((t_h-3.0)-s2);
+ /* u+v = ss*(1+...) */
+ u = s_h*t_h;
+ v = s_l*t_h+t_l*ss;
+ /* 2/(3log2)*(ss+...) */
+ p_h = u+v;
+ SET_LOW_WORD(p_h,0);
+ 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) = (ss+..)*2/(3*log2) = n + dp_h + z_h + z_l */
+ t = (double)n;
+ t1 = (((z_h+z_l)+dp_h[k])+t);
+ SET_LOW_WORD(t1,0);
+ t2 = z_l-(((t1-t)-dp_h[k])-z_h);
+ }
+
+ /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */
+ y1 = y;
+ SET_LOW_WORD(y1,0);
+ p_l = (y-y1)*t1+y*t2;
+ p_h = y1*t1;
+ z = p_l+p_h;
+ EXTRACT_WORDS(j,i,z);
+ if (j>=0x40900000) { /* z >= 1024 */
+ if(((j-0x40900000)|i)!=0) /* if z > 1024 */
+ return s*huge*huge; /* overflow */
+ else {
+ if(p_l+ovt>z-p_h) return s*huge*huge; /* overflow */
+ }
+ } else if((j&0x7fffffff)>=0x4090cc00 ) { /* z <= -1075 */
+ if(((j-0xc090cc00)|i)!=0) /* z < -1075 */
+ return s*tiny*tiny; /* underflow */
+ else {
+ if(p_l<=z-p_h) return s*tiny*tiny; /* underflow */
+ }
+ }
+ /*
+ * compute 2**(p_h+p_l)
+ */
+ i = j&0x7fffffff;
+ k = (i>>20)-0x3ff;
+ n = 0;
+ if(i>0x3fe00000) { /* if |z| > 0.5, set n = [z+0.5] */
+ n = j+(0x00100000>>(k+1));
+ k = ((n&0x7fffffff)>>20)-0x3ff; /* new k for n */
+ t = zero;
+ SET_HIGH_WORD(t,n&~(0x000fffff>>k));
+ n = ((n&0x000fffff)|0x00100000)>>(20-k);
+ if(j<0) n = -n;
+ p_h -= t;
+ }
+ t = p_l+p_h;
+ SET_LOW_WORD(t,0);
+ 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_HIGH_WORD(j,z);
+ j += (n<<20);
+ if((j>>20)<=0) z = scalbn(z,n); /* subnormal output */
+ else SET_HIGH_WORD(z,j);
+ return s*z;
+}