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authorSzabolcs Nagy <szabolcs.nagy@arm.com>2017-09-04 17:53:47 +0100
committerSzabolcs Nagy <szabolcs.nagy@arm.com>2017-09-29 17:17:41 +0100
commit875c76c7048fe4a8c67c265cdae057cb3ca19f44 (patch)
treeee66c284e87c2a5b62b7d6e39fcdd0295bd058cc /NEWS
parent90c42e40d06ee35c4a2206fa2e00f49a988ee0c1 (diff)
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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 'NEWS')
-rw-r--r--NEWS2
1 files changed, 1 insertions, 1 deletions
diff --git a/NEWS b/NEWS
index 05850f8288..5e88c54a6b 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.
+* Optimized generic expf, exp2f, logf, log2f.
 
 * In order to support faster and safer process termination the malloc API
   family of functions will no longer print a failure address and stack