Module Name:	syssrc
Committed By:	itohy
Date:		Sat Aug 24 06:30:36 UTC 2002

Added Files:
	basesrc/lib/libc/arch/sh3/string: ffs.S
	syssrc/sys/lib/libkern/arch/sh3: ffs.S

Log Message:
Assembly version of ffs(3).
Confirmed to return the same value as that of the C version.

The results of a simple benchmark on SH-4 200MHz, is shown below.
I think this shows acceptable performance.

return value	C version	this version	speed
of ffs()	(ns/call)	(ns/call)	ratio
------------	---------	------------	-----
 0		  86		 86		1.00
 1		 110		 86		1.27
 2		 132		 86		1.53
 3		 165		105		1.57
 4		 201		104		1.93
 5		 237		111		2.13
 6		 271		111		2.44
 7		 307		126		2.43
 8		 342		125		2.73
 9		 376		122		3.08
10		 410		121		3.38
11		 446		139		3.20
12		 483		140		3.45
13		 518		146		3.54
14		 551		146		3.77
15		 587		161		3.64
16		 624		162		3.85
17		 658		141		4.66
18		 694		142		4.88
19		 727		160		4.54
20		 764		161		4.74
21		 799		167		4.78
22		 834		167		4.99
23		 868		181		4.79
24		 903		181		4.98
25		 939		146		6.43
26		 974		146		6.67
27		1009		166		6.07
28		1044		165		6.32
29		1080		171		6.31
30		1115		171		6.52
31		1151		185		6.22
32		1185		186		6.37


To generate a diff of this commit:
cvs rdiff -r0 -r1.1 basesrc/lib/libc/arch/sh3/string/ffs.S
cvs rdiff -r0 -r1.1 syssrc/sys/lib/libkern/arch/sh3/ffs.S

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.