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| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2017-09-04 17:55:33 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2017-09-29 17:30:53 +0100 |
| commit | 4ea49f4c08eeac1a64a5aba8c9033b604afe8b2c (patch) | |
| tree | a6bae75c1784f4398f6802281ab8ec0034ab2a38 /NEWS | |
| parent | 875c76c7048fe4a8c67c265cdae057cb3ca19f44 (diff) | |
| download | glibc-4ea49f4c08eeac1a64a5aba8c9033b604afe8b2c.tar.gz glibc-4ea49f4c08eeac1a64a5aba8c9033b604afe8b2c.tar.xz glibc-4ea49f4c08eeac1a64a5aba8c9033b604afe8b2c.zip | |
New generic powf
without wrapper on aarch64: powf reciprocal-throughput: 4.2x faster powf latency: 2.6x faster old worst-case error: 1.11 ulp new worst-case error: 0.82 ulp aarch64 .text size: -780 bytes aarch64 .rodata size: +144 bytes powf(x,y) is implemented as exp2(y*log2(x)) with the same algorithms that are used in exp2f and log2f, except that the log2f polynomial is larger for extra precision and its output (and exp2f input) may be scaled by a power of 2 (POWF_SCALE) to simplify the argument reduction step of exp2 (possible when efficient round and convert toint operation is available). The special case handling tries to minimize the checks in the hot path. When the input of exp2_inline is checked, int arithmetics is used as that was faster on the tested aarch64 cores. * math/Makefile (type-float-routines): Add e_powf_log2_data. * sysdeps/ieee754/flt-32/e_powf.c: New implementation. * sysdeps/ieee754/flt-32/e_powf_log2_data.c: New file. * sysdeps/ieee754/flt-32/math_config.h (__powf_log2_data): Define. (issignalingf_inline): Likewise. (POWF_LOG2_TABLE_BITS): Likewise. (POWF_LOG2_POLY_ORDER): Likewise. (POWF_SCALE_BITS): Likewise. (POWF_SCALE): Likewise. * sysdeps/i386/fpu/e_powf_log2_data.c: New file. * sysdeps/ia64/fpu/e_powf_log2_data.c: New file. * sysdeps/m68k/m680x0/fpu/e_powf_log2_data.c: New file.
Diffstat (limited to 'NEWS')
| -rw-r--r-- | NEWS | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/NEWS b/NEWS index 5e88c54a6b..f5821411ca 100644 --- a/NEWS +++ b/NEWS @@ -14,7 +14,7 @@ Major new features: * Optimized x86-64 trunc and truncf for processors with SSE4.1. -* Optimized generic expf, exp2f, logf, log2f. +* Optimized generic expf, exp2f, logf, log2f and powf. * In order to support faster and safer process termination the malloc API family of functions will no longer print a failure address and stack |