From owner-freebsd-questions Thu Apr 19 14:45:38 2001 Delivered-To: freebsd-questions@freebsd.org Received: from guru.mired.org (okc-65-26-235-186.mmcable.com [65.26.235.186]) by hub.freebsd.org (Postfix) with SMTP id 6BC5737B423 for ; Thu, 19 Apr 2001 14:45:33 -0700 (PDT) (envelope-from mwm@mired.org) Received: (qmail 66618 invoked by uid 100); 19 Apr 2001 21:45:32 -0000 From: Mike Meyer MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15071.23675.966064.330382@guru.mired.org> Date: Thu, 19 Apr 2001 16:45:31 -0500 To: "Charles Burns" Cc: questions@freebsd.org Subject: Re: the AMD factor in FreeBSD In-Reply-To: <100472025@toto.iv> X-Mailer: VM 6.90 under 21.1 (patch 14) "Cuyahoga Valley" XEmacs Lucid X-face: "5Mnwy%?j>IIV\)A=):rjWL~NB2aH[}Yq8Z=u~vJ`"(,&SiLvbbz2W`;h9L,Yg`+vb1>RG% *h+%X^n0EZd>TM8_IB;a8F?(Fb"lw'IgCoyM.[Lg#r\ Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Charles Burns types: > You are quite right though, modern x86 CPUs translate everything to RISC > micro-ops befor processing them. RISC is pretty much vertical microcode. WISC - which didn't make quite the same splash - is pretty much horizontal microcode. People wanting to build fast CISC computers have done so by microcoding them for a long time, usually using vertical microcode. The 370 line was that way, as well the high end of the PDP-11 line was that way. Seymour Cray didn't have to implement a CISC instruction set, so the Cray I instruction set is very RISC-like, with the exception of the instructions for dealing with the array processor hanging off the back. The truly cool machines had a writable control store. The PDP-11 kit sold by Heathkit included that as an option. BBN had the ultimate Unix version, though - they included a C compiler and WCS linker so you could write new instructions in C, so your function calls turned into single instructions. My favorite microcode oddity is the IBM PC card IBM sold that used a 68K chip with custom microcode to interpret 370 machine instructions so you could run MVS software on your x86 PC. Ok, enough reminiscing for one day. http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message