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| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2017-09-04 17:53:47 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2017-09-29 17:17:41 +0100 |
| commit | 875c76c7048fe4a8c67c265cdae057cb3ca19f44 (patch) | |
| tree | ee66c284e87c2a5b62b7d6e39fcdd0295bd058cc /sysdeps/ieee754/flt-32/e_log2f_data.c | |
| parent | 90c42e40d06ee35c4a2206fa2e00f49a988ee0c1 (diff) | |
| download | glibc-875c76c7048fe4a8c67c265cdae057cb3ca19f44.tar.xz glibc-875c76c7048fe4a8c67c265cdae057cb3ca19f44.zip | |
New generic log2f
Similar to the new logf: double precision arithmetics and a small
lookup table is used. The argument reduction step is the same as in
the new logf.
without wrapper on aarch64:
log2f reciprocal-throughput: 2.3x faster
log2f latency: 2.1x faster
old worst case error: 1.72 ulp
new worst case error: 0.75 ulp
aarch64 .text size: -252 bytes
aarch64 .rodata size: +244 bytes
* math/Makefile (type-float-routines): Add e_log2f_data.
* sysdeps/ieee754/flt-32/e_log2f.c: New implementation.
* sysdeps/ieee754/flt-32/e_log2f_data.c: New file.
* sysdeps/ieee754/flt-32/math_config.h (__log2f_data): Define.
(LOG2F_TABLE_BITS, LOG2F_POLY_ORDER): Define.
* sysdeps/i386/fpu/e_log2f_data.c: New file.
* sysdeps/ia64/fpu/e_log2f_data.c: New file.
* sysdeps/m68k/m680x0/fpu/e_log2f_data.c: New file.
Diffstat (limited to 'sysdeps/ieee754/flt-32/e_log2f_data.c')
| -rw-r--r-- | sysdeps/ieee754/flt-32/e_log2f_data.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/sysdeps/ieee754/flt-32/e_log2f_data.c b/sysdeps/ieee754/flt-32/e_log2f_data.c new file mode 100644 index 0000000000..e39de3ba56 --- /dev/null +++ b/sysdeps/ieee754/flt-32/e_log2f_data.c @@ -0,0 +1,44 @@ +/* Data definition for log2f. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include "math_config.h" + +const struct log2f_data __log2f_data = { + .tab = { + { 0x1.661ec79f8f3bep+0, -0x1.efec65b963019p-2 }, + { 0x1.571ed4aaf883dp+0, -0x1.b0b6832d4fca4p-2 }, + { 0x1.49539f0f010bp+0, -0x1.7418b0a1fb77bp-2 }, + { 0x1.3c995b0b80385p+0, -0x1.39de91a6dcf7bp-2 }, + { 0x1.30d190c8864a5p+0, -0x1.01d9bf3f2b631p-2 }, + { 0x1.25e227b0b8eap+0, -0x1.97c1d1b3b7afp-3 }, + { 0x1.1bb4a4a1a343fp+0, -0x1.2f9e393af3c9fp-3 }, + { 0x1.12358f08ae5bap+0, -0x1.960cbbf788d5cp-4 }, + { 0x1.0953f419900a7p+0, -0x1.a6f9db6475fcep-5 }, + { 0x1p+0, 0x0p+0 }, + { 0x1.e608cfd9a47acp-1, 0x1.338ca9f24f53dp-4 }, + { 0x1.ca4b31f026aap-1, 0x1.476a9543891bap-3 }, + { 0x1.b2036576afce6p-1, 0x1.e840b4ac4e4d2p-3 }, + { 0x1.9c2d163a1aa2dp-1, 0x1.40645f0c6651cp-2 }, + { 0x1.886e6037841edp-1, 0x1.88e9c2c1b9ff8p-2 }, + { 0x1.767dcf5534862p-1, 0x1.ce0a44eb17bccp-2 }, + }, + .poly = { + -0x1.712b6f70a7e4dp-2, 0x1.ecabf496832ep-2, -0x1.715479ffae3dep-1, + 0x1.715475f35c8b8p0, + } +}; |