Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: BitScan with reset - not so impressive with 3DNow!

Author: Alessandro Damiani

Date: 02:05:24 12/03/02

Go up one level in this thread


On December 02, 2002 at 21:01:05, Walter Faxon wrote:

>On December 02, 2002 at 19:43:15, Gerd Isenberg wrote:
>
><snip>
>>
>>Congrats, Walter!!
>>
>>10-bit pattern		bsf	PI2FD	btr	c      LSB_64
>>0x0000000011111133	15.3	18.0	19.1	22.8    17.8
>>0x1010111010101110	19.7	18.5	19.6	23.4    17.8
>>0x1111113300000000	20.6	18.0	19.1	22.8    17.8
>>
><snip>
>>
>>Geniously, sorry Walter, that i overlooked your approach. It is clearly the
>>fastest of these routines. De Bruijn Sequence? May have a close look to the
>>constant.
>>
>>I'm really impressed.
>>
>>Regards,
>>Gerd
>
>
>Thanks, Gerd.  It was based on 32-bit code I wrote in 1992, for the 80386 with
>its 10+3n clocks on the bsf instruction.  Both versions were written without
>knowledge of De Bruijn.  Thank you very much for your public testing.  Maybe now
>the result won't be lost! :)
>

Yeah! Now I opened my eyes. :)

Alessandro




This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.