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994007ff29
The libm size improvement built with "--enable-stack-protector=strong --enable-bind-now=yes --enable-fortify-source=2": Before: text data bss dec hex filename 587304 860 12 588176 8f990 aarch64-linux-gnu-master/math/libm.so 962855 1068 12 963935 eb55f x86_64-linux-gnu-master/math/libm.so 1191222 5544 368 1197134 12444e powerpc64le-linux-gnu-master/math/libm.so After: text data bss dec hex filename 585192 860 12 586064 8f150 aarch64-linux-gnu/math/libm.so 960775 1068 12 961855 ead3f x86_64-linux-gnu/math/libm.so 1189174 5544 368 1195086 123c4e powerpc64le-linux-gnu/math/libm.so The are small code changes for x86_64 and powerpc64le, which do not affect performance; but on aarch64 with gcc-14 I see a slight better code generation due the usage of ldq for floating point constant loading. Reviewed-by: Andreas K. Huettel <dilfridge@gentoo.org>
109 lines
3.5 KiB
C
109 lines
3.5 KiB
C
/* Correctly-rounded inverse hyperbolic cosine function for binary32 format.
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Copyright (c) 2023-2024 Alexei Sibidanov.
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The original version of this file was copied from the CORE-MATH
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project (file src/binary32/acosh/acoshf.c, revision d0b9ddd).
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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#include <math.h>
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#include <stdint.h>
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#include <libm-alias-finite.h>
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#include "math_config.h"
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#include "s_asincoshf_data.h"
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static __attribute__ ((noinline)) float
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as_special (float x)
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{
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uint32_t t = asuint (x);
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if (t == 0x3f800000u)
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return 0.0f;
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if ((t << 1) > 0xff000000u)
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return x + x; /* nan */
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if (t == 0x7f800000u)
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return x; /* inf */
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return __math_invalidf (x);
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}
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float
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__ieee754_acoshf (float x)
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{
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uint32_t t = asuint (x);
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if (__glibc_unlikely (t <= 0x3f800000u))
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return as_special (x);
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else if (__glibc_unlikely (t <= 0x3f99db23u)) /* x <= 0x1.33b646p+0 */
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{
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float zf = x - 1.0f;
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double z = zf;
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double a = sqrt (2.0 * z);
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static const double c[] =
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{
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-0x1.555555555491ep-4, 0x1.333333319c2p-6,
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-0x1.6db6da26e5e0ep-8, 0x1.f1c698b7100cep-10,
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-0x1.6e7ca9e152dc2p-11, 0x1.1b4cf187158bdp-12,
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-0x1.b5137f11a88e5p-14, 0x1.056c6c57152b2p-15
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};
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double z2 = z * z;
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double z4 = z2 * z2;
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double f = ((c[0] + z * c[1]) + z2 * (c[2] + z * c[3]))
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+ z4 * ((c[4] + z * c[5]) + z2 * (c[6] + z * c[7]));
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double r = a + (a * z) * f;
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return r;
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}
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else if (__glibc_likely (t < 0x7f800000u))
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{
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double xd = x;
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double x2 = xd * xd;
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uint64_t tp = asuint64 (xd + sqrt (x2 - 1));
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uint64_t m = tp & (~UINT64_C(0) >> 12);
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int j = (m + (UINT64_C(1) << (52 - 8))) >> (52 - 7);
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int e = (tp >> 52) - 0x3ff;
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double w = asdouble (m | UINT64_C(0x3ff) << 52);
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double z = w * IX[j] - 1.0;
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double z2 = z * z;
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double r = ((LIX[128] * e + LIX[j]) + z * C[0])
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+ z2 * (C[1] + z * C[2]);
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if (__glibc_unlikely (((asuint64 (r) + 259000) & INT64_C(0xfffffff))
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< 260000)) /* accurate path */
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{
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z2 = z * z;
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double c0 = CP[0] + z * CP[1];
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double c2 = CP[2] + z * CP[3];
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double c4 = CP[4] + z * CP[5];
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c0 += z2 * (c2 + z2 * c4);
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const double ln2l = 0x1.7f7d1cf79abcap-20;
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const double ln2h = 0x1.62e4p-1;
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double Lh = ln2h * e;
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double Ll = ln2l * e;
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r = fma (z, c0, Ll + LIX[j]) + Lh;
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if (__glibc_unlikely ((asuint64 (r) & UINT64_C(0xfffffff)) == 0))
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{
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double h = fma (z, c0, Ll + LIX[j]) + (Lh - r);
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r = r + 64.0 * h;
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}
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}
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return r;
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}
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else
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return as_special (x);
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}
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libm_alias_finite (__ieee754_acoshf, __acoshf)
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