Newsgroups: comp.sys.cbm
Path: utzoo!utgpu!watserv1!maytag!xenitec!geoffw
From: geoffw@xenitec.on.ca (Geoffrey Welsh)
Subject: Re: terminal progs?
Reply-To: root@zswamp.fidonet.org (Geoffrey Welsh)
Organization: XeniTec Consulting Services, Kitchener, ON, Canada
Date: Wed, 19 Sep 90 23:09:45 GMT
Message-ID: <1990Sep19.230945.26660@xenitec.on.ca>
References: <XX00011d08@pallio.UUCP>

In article <XX00011d08@pallio.UUCP> dg@pallio.UUCP (David Goodenough) writes:
>After having seen the Z80 code in their CP/M BIOS, I'd have to agree
>with that. I'm a CP/M / Z80 programmer rather than 6510 / 8502, so that
>opinion is based on the CP/M code. Suffice it to say they have a CPU
>clocked at something like 6 MHz, but it gets a throughput of about 2 MHz.
>I.e. they are wasting 65% of the CPU's horsepower in badly written
>interrupt and screen I/O drivers.

   Actually, the Z80 is clocked at 4 MHz, but runs two cycles on/
two cycles off to accomodate the VIC chip's DMA. That is where it
gets its 'effective' 2 MHz speed.

UUCP:     watmath!xenitec!zswamp!root | 602-66 Mooregate Crescent
Internet: root@zswamp.fidonet.org     | Kitchener, Ontario
FidoNet:  SYSOP, 1:221/171            | N2M 5E6 CANADA
Data:     (519) 742-8939              | (519) 741-9553
My comments do not represent and should not obligate anyone but myself.
