From owner-freebsd-hackers Thu Nov 9 01:59:33 1995 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id BAA02193 for hackers-outgoing; Thu, 9 Nov 1995 01:59:33 -0800 Received: from tfs.com (tfs.com [140.145.250.1]) by freefall.freebsd.org (8.6.12/8.6.6) with SMTP id BAA02187 for ; Thu, 9 Nov 1995 01:59:28 -0800 Received: from critter.tfs.com by tfs.com (smail3.1.28.1) with SMTP id m0tDTlL-0003x2C; Thu, 9 Nov 95 01:59 PST Received: from localhost (localhost [127.0.0.1]) by critter.tfs.com (8.6.11/8.6.9) with SMTP id JAA06342; Thu, 9 Nov 1995 09:40:03 +0100 X-Authentication-Warning: critter.tfs.com: Host localhost didn't use HELO protocol To: Michael Smith cc: hackers@freebsd.org Subject: Re: Load/Store using FPU regs ... In-reply-to: Your message of "Thu, 09 Nov 1995 09:01:31 GMT." <199511090901.JAA09519@genesis.atrad.adelaide.edu.au> Date: Thu, 09 Nov 1995 09:40:03 +0100 Message-ID: <6340.815906403@critter.tfs.com> From: Poul-Henning Kamp Sender: owner-hackers@freebsd.org Precedence: bulk > koshy@blr.novell.com stands accused of saying: > > >>> L20: fldl (%ebx) fstpl (%ecx) ... > > >>> > > >>> The resulting program copies data at about 60 Megabytes per > > >>> second. > > > > > > Using the FPU registers for memmove/bitblt operations was a technique > > I first saw on an i860. We used to do a series of reads into FPU regs > > Wheras those of us with 68K backgrounds are rolling in the aisles about > this one 8) > > (For the uninitiated; the 68K can read/write arbitrary groups of registers > and increment/decrement the source/destination pointers at the same time. > Depending on coding technique, you can read or write as much as 56 > bytes at a time; the big win (microcoded processor, remember) being no > instruction fetches between reads. It's a pity that Motorola have axed > it as a mainstram family 8( ) > > Anyway, enough from the nostalgia corner - I'm too young for this! What you really want of course is a "outside the cache" bzero and bcopy function... -- Poul-Henning Kamp | phk@FreeBSD.ORG FreeBSD Core-team. http://www.freebsd.org/~phk | phk@login.dknet.dk Private mailbox. whois: [PHK] | phk@ref.tfs.com TRW Financial Systems, Inc. Future will arrive by its own means, progress not so.