Date: Thu, 9 Nov 1995 09:01:31 +0000 () From: Michael Smith <msmith@atrad.adelaide.edu.au> To: hackers@freebsd.org Subject: Re: Load/Store using FPU regs ... Message-ID: <199511090901.JAA09519@genesis.atrad.adelaide.edu.au> In-Reply-To: <30a1bccf0.4265@novidc.blr.novell.com> from "koshy@blr.novell.com" at Nov 9, 95 02:03:00 pm
next in thread | previous in thread | raw e-mail | index | archive | help
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! -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 041-122-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] My car has "demand start" -Terry Lambert UNIX: live FreeBSD or die! [[
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199511090901.JAA09519>