auto import from //depot/cupcake/@135843
diff --git a/libm/bsdsrc/b_tgamma.c b/libm/bsdsrc/b_tgamma.c
new file mode 100644
index 0000000..ff6c5ac
--- /dev/null
+++ b/libm/bsdsrc/b_tgamma.c
@@ -0,0 +1,316 @@
+/*-
+ * Copyright (c) 1992, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)gamma.c 8.1 (Berkeley) 6/4/93";
+#endif /* not lint */
+#include <sys/cdefs.h>
+/* __FBSDID("$FreeBSD: src/lib/msun/bsdsrc/b_tgamma.c,v 1.7 2005/09/19 11:28:19 bde Exp $"); */
+
+/*
+ * This code by P. McIlroy, Oct 1992;
+ *
+ * The financial support of UUNET Communications Services is greatfully
+ * acknowledged.
+ */
+
+//#include <math.h>
+#include "../include/math.h"
+#include "mathimpl.h"
+#include <errno.h>
+
+/* METHOD:
+ * x < 0: Use reflection formula, G(x) = pi/(sin(pi*x)*x*G(x))
+ * At negative integers, return +Inf, and set errno.
+ *
+ * x < 6.5:
+ * Use argument reduction G(x+1) = xG(x) to reach the
+ * range [1.066124,2.066124]. Use a rational
+ * approximation centered at the minimum (x0+1) to
+ * ensure monotonicity.
+ *
+ * x >= 6.5: Use the asymptotic approximation (Stirling's formula)
+ * adjusted for equal-ripples:
+ *
+ * log(G(x)) ~= (x-.5)*(log(x)-1) + .5(log(2*pi)-1) + 1/x*P(1/(x*x))
+ *
+ * Keep extra precision in multiplying (x-.5)(log(x)-1), to
+ * avoid premature round-off.
+ *
+ * Special values:
+ * non-positive integer: Set overflow trap; return +Inf;
+ * x > 171.63: Set overflow trap; return +Inf;
+ * NaN: Set invalid trap; return NaN
+ *
+ * Accuracy: Gamma(x) is accurate to within
+ * x > 0: error provably < 0.9ulp.
+ * Maximum observed in 1,000,000 trials was .87ulp.
+ * x < 0:
+ * Maximum observed error < 4ulp in 1,000,000 trials.
+ */
+
+static double neg_gam(double);
+static double small_gam(double);
+static double smaller_gam(double);
+static struct Double large_gam(double);
+static struct Double ratfun_gam(double, double);
+
+/*
+ * Rational approximation, A0 + x*x*P(x)/Q(x), on the interval
+ * [1.066.., 2.066..] accurate to 4.25e-19.
+ */
+#define LEFT -.3955078125 /* left boundary for rat. approx */
+#define x0 .461632144968362356785 /* xmin - 1 */
+
+#define a0_hi 0.88560319441088874992
+#define a0_lo -.00000000000000004996427036469019695
+#define P0 6.21389571821820863029017800727e-01
+#define P1 2.65757198651533466104979197553e-01
+#define P2 5.53859446429917461063308081748e-03
+#define P3 1.38456698304096573887145282811e-03
+#define P4 2.40659950032711365819348969808e-03
+#define Q0 1.45019531250000000000000000000e+00
+#define Q1 1.06258521948016171343454061571e+00
+#define Q2 -2.07474561943859936441469926649e-01
+#define Q3 -1.46734131782005422506287573015e-01
+#define Q4 3.07878176156175520361557573779e-02
+#define Q5 5.12449347980666221336054633184e-03
+#define Q6 -1.76012741431666995019222898833e-03
+#define Q7 9.35021023573788935372153030556e-05
+#define Q8 6.13275507472443958924745652239e-06
+/*
+ * Constants for large x approximation (x in [6, Inf])
+ * (Accurate to 2.8*10^-19 absolute)
+ */
+#define lns2pi_hi 0.418945312500000
+#define lns2pi_lo -.000006779295327258219670263595
+#define Pa0 8.33333333333333148296162562474e-02
+#define Pa1 -2.77777777774548123579378966497e-03
+#define Pa2 7.93650778754435631476282786423e-04
+#define Pa3 -5.95235082566672847950717262222e-04
+#define Pa4 8.41428560346653702135821806252e-04
+#define Pa5 -1.89773526463879200348872089421e-03
+#define Pa6 5.69394463439411649408050664078e-03
+#define Pa7 -1.44705562421428915453880392761e-02
+
+static const double zero = 0., one = 1.0, tiny = 1e-300;
+
+double
+tgamma(x)
+ double x;
+{
+ struct Double u;
+
+ if (x >= 6) {
+ if(x > 171.63)
+ return(one/zero);
+ u = large_gam(x);
+ return(__exp__D(u.a, u.b));
+ } else if (x >= 1.0 + LEFT + x0)
+ return (small_gam(x));
+ else if (x > 1.e-17)
+ return (smaller_gam(x));
+ else if (x > -1.e-17) {
+ if (x == 0.0)
+ return (one/x);
+ one+1e-20; /* Raise inexact flag. */
+ return (one/x);
+ } else if (!finite(x))
+ return (x*x); /* x = NaN, -Inf */
+ else
+ return (neg_gam(x));
+}
+/*
+ * Accurate to max(ulp(1/128) absolute, 2^-66 relative) error.
+ */
+static struct Double
+large_gam(x)
+ double x;
+{
+ double z, p;
+ struct Double t, u, v;
+
+ z = one/(x*x);
+ p = Pa0+z*(Pa1+z*(Pa2+z*(Pa3+z*(Pa4+z*(Pa5+z*(Pa6+z*Pa7))))));
+ p = p/x;
+
+ u = __log__D(x);
+ u.a -= one;
+ v.a = (x -= .5);
+ TRUNC(v.a);
+ v.b = x - v.a;
+ t.a = v.a*u.a; /* t = (x-.5)*(log(x)-1) */
+ t.b = v.b*u.a + x*u.b;
+ /* return t.a + t.b + lns2pi_hi + lns2pi_lo + p */
+ t.b += lns2pi_lo; t.b += p;
+ u.a = lns2pi_hi + t.b; u.a += t.a;
+ u.b = t.a - u.a;
+ u.b += lns2pi_hi; u.b += t.b;
+ return (u);
+}
+/*
+ * Good to < 1 ulp. (provably .90 ulp; .87 ulp on 1,000,000 runs.)
+ * It also has correct monotonicity.
+ */
+static double
+small_gam(x)
+ double x;
+{
+ double y, ym1, t;
+ struct Double yy, r;
+ y = x - one;
+ ym1 = y - one;
+ if (y <= 1.0 + (LEFT + x0)) {
+ yy = ratfun_gam(y - x0, 0);
+ return (yy.a + yy.b);
+ }
+ r.a = y;
+ TRUNC(r.a);
+ yy.a = r.a - one;
+ y = ym1;
+ yy.b = r.b = y - yy.a;
+ /* Argument reduction: G(x+1) = x*G(x) */
+ for (ym1 = y-one; ym1 > LEFT + x0; y = ym1--, yy.a--) {
+ t = r.a*yy.a;
+ r.b = r.a*yy.b + y*r.b;
+ r.a = t;
+ TRUNC(r.a);
+ r.b += (t - r.a);
+ }
+ /* Return r*tgamma(y). */
+ yy = ratfun_gam(y - x0, 0);
+ y = r.b*(yy.a + yy.b) + r.a*yy.b;
+ y += yy.a*r.a;
+ return (y);
+}
+/*
+ * Good on (0, 1+x0+LEFT]. Accurate to 1ulp.
+ */
+static double
+smaller_gam(x)
+ double x;
+{
+ double t, d;
+ struct Double r, xx;
+ if (x < x0 + LEFT) {
+ t = x, TRUNC(t);
+ d = (t+x)*(x-t);
+ t *= t;
+ xx.a = (t + x), TRUNC(xx.a);
+ xx.b = x - xx.a; xx.b += t; xx.b += d;
+ t = (one-x0); t += x;
+ d = (one-x0); d -= t; d += x;
+ x = xx.a + xx.b;
+ } else {
+ xx.a = x, TRUNC(xx.a);
+ xx.b = x - xx.a;
+ t = x - x0;
+ d = (-x0 -t); d += x;
+ }
+ r = ratfun_gam(t, d);
+ d = r.a/x, TRUNC(d);
+ r.a -= d*xx.a; r.a -= d*xx.b; r.a += r.b;
+ return (d + r.a/x);
+}
+/*
+ * returns (z+c)^2 * P(z)/Q(z) + a0
+ */
+static struct Double
+ratfun_gam(z, c)
+ double z, c;
+{
+ double p, q;
+ struct Double r, t;
+
+ q = Q0 +z*(Q1+z*(Q2+z*(Q3+z*(Q4+z*(Q5+z*(Q6+z*(Q7+z*Q8)))))));
+ p = P0 + z*(P1 + z*(P2 + z*(P3 + z*P4)));
+
+ /* return r.a + r.b = a0 + (z+c)^2*p/q, with r.a truncated to 26 bits. */
+ p = p/q;
+ t.a = z, TRUNC(t.a); /* t ~= z + c */
+ t.b = (z - t.a) + c;
+ t.b *= (t.a + z);
+ q = (t.a *= t.a); /* t = (z+c)^2 */
+ TRUNC(t.a);
+ t.b += (q - t.a);
+ r.a = p, TRUNC(r.a); /* r = P/Q */
+ r.b = p - r.a;
+ t.b = t.b*p + t.a*r.b + a0_lo;
+ t.a *= r.a; /* t = (z+c)^2*(P/Q) */
+ r.a = t.a + a0_hi, TRUNC(r.a);
+ r.b = ((a0_hi-r.a) + t.a) + t.b;
+ return (r); /* r = a0 + t */
+}
+
+static double
+neg_gam(x)
+ double x;
+{
+ int sgn = 1;
+ struct Double lg, lsine;
+ double y, z;
+
+ y = floor(x + .5);
+ if (y == x) /* Negative integer. */
+ return (one/zero);
+ z = fabs(x - y);
+ y = .5*ceil(x);
+ if (y == ceil(y))
+ sgn = -1;
+ if (z < .25)
+ z = sin(M_PI*z);
+ else
+ z = cos(M_PI*(0.5-z));
+ /* Special case: G(1-x) = Inf; G(x) may be nonzero. */
+ if (x < -170) {
+ if (x < -190)
+ return ((double)sgn*tiny*tiny);
+ y = one - x; /* exact: 128 < |x| < 255 */
+ lg = large_gam(y);
+ lsine = __log__D(M_PI/z); /* = TRUNC(log(u)) + small */
+ lg.a -= lsine.a; /* exact (opposite signs) */
+ lg.b -= lsine.b;
+ y = -(lg.a + lg.b);
+ z = (y + lg.a) + lg.b;
+ y = __exp__D(y, z);
+ if (sgn < 0) y = -y;
+ return (y);
+ }
+ y = one-x;
+ if (one-y == x)
+ y = tgamma(y);
+ else /* 1-x is inexact */
+ y = -x*tgamma(-x);
+ if (sgn < 0) y = -y;
+ return (M_PI / (y*z));
+}