Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 138 insertions, 0 deletions

diff --git a/modules/fdlibm/src/s_exp2f.cpp b/modules/fdlibm/src/s_exp2f.cpp
new file mode 100644
index 0000000000..82ec98da94
--- /dev/null
+++ b/modules/fdlibm/src/s_exp2f.cpp
@@ -0,0 +1,138 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ */
+
+//#include <sys/cdefs.h>
+//__FBSDID("$FreeBSD$");
+
+#include <float.h>
+
+#include "math_private.h"
+
+#define	TBLBITS	4
+#define	TBLSIZE	(1 << TBLBITS)
+
+static const float
+    redux   = 0x1.8p23f / TBLSIZE,
+    P1	    = 0x1.62e430p-1f,
+    P2	    = 0x1.ebfbe0p-3f,
+    P3	    = 0x1.c6b348p-5f,
+    P4	    = 0x1.3b2c9cp-7f;
+
+static volatile float
+    huge    = 0x1p100f,
+    twom100 = 0x1p-100f;
+
+static const double exp2ft[TBLSIZE] = {
+	0x1.6a09e667f3bcdp-1,
+	0x1.7a11473eb0187p-1,
+	0x1.8ace5422aa0dbp-1,
+	0x1.9c49182a3f090p-1,
+	0x1.ae89f995ad3adp-1,
+	0x1.c199bdd85529cp-1,
+	0x1.d5818dcfba487p-1,
+	0x1.ea4afa2a490dap-1,
+	0x1.0000000000000p+0,
+	0x1.0b5586cf9890fp+0,
+	0x1.172b83c7d517bp+0,
+	0x1.2387a6e756238p+0,
+	0x1.306fe0a31b715p+0,
+	0x1.3dea64c123422p+0,
+	0x1.4bfdad5362a27p+0,
+	0x1.5ab07dd485429p+0,
+};
+	
+/*
+ * exp2f(x): compute the base 2 exponential of x
+ *
+ * Accuracy: Peak error < 0.501 ulp; location of peak: -0.030110927.
+ *
+ * Method: (equally-spaced tables)
+ *
+ *   Reduce x:
+ *     x = 2**k + y, for integer k and |y| <= 1/2.
+ *     Thus we have exp2f(x) = 2**k * exp2(y).
+ *
+ *   Reduce y:
+ *     y = i/TBLSIZE + z for integer i near y * TBLSIZE.
+ *     Thus we have exp2(y) = exp2(i/TBLSIZE) * exp2(z),
+ *     with |z| <= 2**-(TBLSIZE+1).
+ *
+ *   We compute exp2(i/TBLSIZE) via table lookup and exp2(z) via a
+ *   degree-4 minimax polynomial with maximum error under 1.4 * 2**-33.
+ *   Using double precision for everything except the reduction makes
+ *   roundoff error insignificant and simplifies the scaling step.
+ *
+ *   This method is due to Tang, but I do not use his suggested parameters:
+ *
+ *	Tang, P.  Table-driven Implementation of the Exponential Function
+ *	in IEEE Floating-Point Arithmetic.  TOMS 15(2), 144-157 (1989).
+ */
+float
+exp2f(float x)
+{
+	double tv, twopk, u, z;
+	float t;
+	uint32_t hx, ix, i0;
+	int32_t k;
+
+	/* Filter out exceptional cases. */
+	GET_FLOAT_WORD(hx, x);
+	ix = hx & 0x7fffffff;		/* high word of |x| */
+	if(ix >= 0x43000000) {			/* |x| >= 128 */
+		if(ix >= 0x7f800000) {
+			if ((ix & 0x7fffff) != 0 || (hx & 0x80000000) == 0)
+				return (x + x);	/* x is NaN or +Inf */
+			else 
+				return (0.0);	/* x is -Inf */
+		}
+		if(x >= 0x1.0p7f)
+			return (huge * huge);	/* overflow */
+		if(x <= -0x1.2cp7f)
+			return (twom100 * twom100); /* underflow */
+	} else if (ix <= 0x33000000) {		/* |x| <= 0x1p-25 */
+		return (1.0f + x);
+	}
+
+	/* Reduce x, computing z, i0, and k. */
+	STRICT_ASSIGN(float, t, x + redux);
+	GET_FLOAT_WORD(i0, t);
+	i0 += TBLSIZE / 2;
+	k = (i0 >> TBLBITS) << 20;
+	i0 &= TBLSIZE - 1;
+	t -= redux;
+	z = x - t;
+	INSERT_WORDS(twopk, 0x3ff00000 + k, 0);
+
+	/* Compute r = exp2(y) = exp2ft[i0] * p(z). */
+	tv = exp2ft[i0];
+	u = tv * z;
+	tv = tv + u * (P1 + z * P2) + u * (z * z) * (P3 + z * P4);
+
+	/* Scale by 2**(k>>20). */
+	return (tv * twopk);
+}