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authorIan Moffett <ian@osmora.org>2024-03-07 17:28:52 -0500
committerIan Moffett <ian@osmora.org>2024-03-07 18:24:51 -0500
commitf5e48e94a2f4d4bbd6e5628c7f2afafc6dbcc459 (patch)
tree93b156621dc0303816b37f60ba88051b702d92f6 /lib/mlibc/options/ansi/musl-generic-math/exp2f.c
parentbd5969fc876a10b18613302db7087ef3c40f18e1 (diff)
build: Build mlibc + add distclean target
Signed-off-by: Ian Moffett <ian@osmora.org>
Diffstat (limited to 'lib/mlibc/options/ansi/musl-generic-math/exp2f.c')
-rw-r--r--lib/mlibc/options/ansi/musl-generic-math/exp2f.c126
1 files changed, 0 insertions, 126 deletions
diff --git a/lib/mlibc/options/ansi/musl-generic-math/exp2f.c b/lib/mlibc/options/ansi/musl-generic-math/exp2f.c
deleted file mode 100644
index 296b634..0000000
--- a/lib/mlibc/options/ansi/musl-generic-math/exp2f.c
+++ /dev/null
@@ -1,126 +0,0 @@
-/* origin: FreeBSD /usr/src/lib/msun/src/s_exp2f.c */
-/*-
- * 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 "libm.h"
-
-#define TBLSIZE 16
-
-static const float
-redux = 0x1.8p23f / TBLSIZE,
-P1 = 0x1.62e430p-1f,
-P2 = 0x1.ebfbe0p-3f,
-P3 = 0x1.c6b348p-5f,
-P4 = 0x1.3b2c9cp-7f;
-
-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 = 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_t t, r, z;
- union {float f; uint32_t i;} u = {x};
- union {double f; uint64_t i;} uk;
- uint32_t ix, i0, k;
-
- /* Filter out exceptional cases. */
- ix = u.i & 0x7fffffff;
- if (ix > 0x42fc0000) { /* |x| > 126 */
- if (ix > 0x7f800000) /* NaN */
- return x;
- if (u.i >= 0x43000000 && u.i < 0x80000000) { /* x >= 128 */
- x *= 0x1p127f;
- return x;
- }
- if (u.i >= 0x80000000) { /* x < -126 */
- if (u.i >= 0xc3160000 || (u.i & 0x0000ffff))
- FORCE_EVAL(-0x1p-149f/x);
- if (u.i >= 0xc3160000) /* x <= -150 */
- return 0;
- }
- } else if (ix <= 0x33000000) { /* |x| <= 0x1p-25 */
- return 1.0f + x;
- }
-
- /* Reduce x, computing z, i0, and k. */
- u.f = x + redux;
- i0 = u.i;
- i0 += TBLSIZE / 2;
- k = i0 / TBLSIZE;
- uk.i = (uint64_t)(0x3ff + k)<<52;
- i0 &= TBLSIZE - 1;
- u.f -= redux;
- z = x - u.f;
- /* Compute r = exp2(y) = exp2ft[i0] * p(z). */
- r = exp2ft[i0];
- t = r * z;
- r = r + t * (P1 + z * P2) + t * (z * z) * (P3 + z * P4);
-
- /* Scale by 2**k */
- return r * uk.f;
-}