Date: Thu, 9 Aug 2001 15:41:49 -0500 From: Mike Meyer <mwm@mired.org> To: David Scheidt <dscheidt@enteract.com> Cc: Dag-Erling Smorgrav <des@ofug.org>, Mike Meyer <mwm@mired.org>, Greg Lehey <grog@FreeBSD.ORG>, <tlambert2@mindspring.com>, j mckitrick <jcm@FreeBSD-uk.eu.org>, <freebsd-chat@FreeBSD.ORG> Subject: Re: How did the MSFT monopoly start? Message-ID: <15218.62861.955183.430680@guru.mired.org> In-Reply-To: <Pine.BSF.4.32L2.0108091238510.70995-100000@shell-2.enteract.com> References: <xzpelql4ms3.fsf@flood.ping.uio.no> <Pine.BSF.4.32L2.0108091238510.70995-100000@shell-2.enteract.com>
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David Scheidt <dscheidt@enteract.com> types: > On 9 Aug 2001, Dag-Erling Smorgrav wrote: > :Mike Meyer <mwm@mired.org> writes: > :> address space was 32 bits - the top 8 got thrown away when you left > :> the CPU - and it didn't have special registers for addressing, so the > :> general registers had to be 32 bits wide and it had to have those 32 > :> bit operations. > :AFAIK, the 68k has separate data and address registers (d0-d7 and > :a0-a7 respectively) > You can use them all as general purpose registers. There might be some > restrictions, but I can't remember any. It's been quite a while though. Of > course, an OS will place restrictions on what registers you can use. No, DES is right. Data registers could be used for pretty much anything but the source of an address. They could be an offset from an address, including an address of 0, which pretty much made that immaterial. Address registers - besides being an address - could only be loaded, added, subtracted and moved. The stack pointer - always(?) a7 - also got tweaked by stack instructions. > Why does 68040 still scream "Oh, fast!" to me, and 1.4 GHz Athlon make me go > "So?" Because you know the 1.4GHz Athlon is going into a system with a system bus most of an order of magnitude slower than 1.4GHz? <mike -- Mike Meyer <mwm@mired.org> 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-chat" in the body of the message
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