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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 /math
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 'math')
-rw-r--r--math/Makefile2
1 files changed, 1 insertions, 1 deletions
diff --git a/math/Makefile b/math/Makefile
index 04586156f8..919fec13ef 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -115,7 +115,7 @@ type-double-routines := branred doasin dosincos halfulp mpa mpatan2	\
 
 # float support
 type-float-suffix := f
-type-float-routines := k_rem_pio2f math_errf e_exp2f_data
+type-float-routines := k_rem_pio2f math_errf e_exp2f_data e_logf_data
 
 # _Float128 support
 type-float128-suffix := f128