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authorSzabolcs Nagy <szabolcs.nagy@arm.com>2017-09-04 17:48:46 +0100
committerSzabolcs Nagy <szabolcs.nagy@arm.com>2017-09-29 11:46:46 +0100
commitbf27d3973d75ed676ea0a0b0dae2fac367d7749b (patch)
treefc32d238bcc9d0440a2e1d0bfeb24eac8396e135 /NEWS
parent4088d8dd29ce0629eeaa7cceca02414c85d98e05 (diff)
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New generic logf
without wrapper on aarch64:
logf reciprocal-throughput: 2.2x faster
logf latency: 1.9x faster
old worst case error: 0.89 ulp
new worst case error: 0.82 ulp
aarch64 .text size: -356 bytes
aarch64 .rodata size: +240 bytes

Uses double precision arithmetics and a lookup table to allow smaller
polynomial and avoid the use of division.

Data is in a separate translation unit with fixed layout to prevent the
compiler generating suboptimal literal access.

Errors are handled inline according to POSIX rules, but this patch
keeps the wrapper with SVID compatible error handling.

Needs libm-test-ulps adjustment for clogf in non-nearest rounding mode.

	* math/Makefile (type-float-routines): Add e_logf_data.
	* sysdeps/ieee754/flt-32/e_logf.c: New implementation.
	* sysdeps/ieee754/flt-32/e_logf_data.c: New file.
	* sysdeps/ieee754/flt-32/math_config.h (__logf_data): Define.
	(LOGF_TABLE_BITS, LOGF_POLY_ORDER): Define.
	* sysdeps/i386/fpu/e_logf_data.c: New file.
	* sysdeps/ia64/fpu/e_logf_data.c: New file.
	* sysdeps/m68k/m680x0/fpu/e_logf_data.c: New file.
Diffstat (limited to 'NEWS')
-rw-r--r--NEWS2
1 files changed, 1 insertions, 1 deletions
diff --git a/NEWS b/NEWS
index e346d2afe6..05850f8288 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 and exp2f.
+* Optimized generic expf, exp2f, logf.
 
 * In order to support faster and safer process termination the malloc API
   family of functions will no longer print a failure address and stack