CVS commit: src/sys/dev/dtv

["Alan Barrett" <apb%netbsd.org@localhost>]

Module Name:    src
Committed By:   apb
Date:           Sat Jul 16 22:30:26 UTC 2011

Modified Files:
        src/sys/dev/dtv: dtv_math.c

Log Message:
Instead of returning an integer between 0 and 31 (scaled by 1<<24), use
(0.5 + x/2 - 1/x) as an approximation to log2(x) for x from 1 to 2, and
scale the input to fit this range.  Now the error is always less than
0.2%.

Also add an test program, hidden behind #ifdef TEST_DTV_MATH, to print
a table of expected and actual results, and the errors.


To generate a diff of this commit:
cvs rdiff -u -r1.2 -r1.3 src/sys/dev/dtv/dtv_math.c

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