Date: Wed, 10 Apr 1996 17:29:24 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: terry@lambert.org (Terry Lambert) Cc: Brett_Glass@ccgate.infoworld.com, terry@lambert.org, questions@FreeBSD.org Subject: Re: Artisoft AE-3 Ethernet card: How to use large buffer? Message-ID: <199604100759.RAA22630@genesis.atrad.adelaide.edu.au> In-Reply-To: <199604100104.SAA06406@phaeton.artisoft.com> from "Terry Lambert" at Apr 9, 96 06:04:34 pm
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Terry Lambert stands accused of saying: > > > I'm not sure, but I believe that the internal buffer is not directly > > accessible on NE2000 clones. As I understand it, the RAM is accessible via > > programmed I/O after setting a pointer register. (This is one of the common > > criticisms of the architecture: PIO isn't quite as fast as shared memory.) Brett is correct here, in that memory on the NEx000 cards is not directly mapped. > > > You need to set mem_end to mem_start + 64k. This should be done in > > > whichever probe routine is coming true. > > > > Aren't the mem_end and mem_start parameters used for cards that have shared > > memory (rather than a PIO/counter scheme)? There are different I/O routines used depending on the card type; see the ed_pio_* routines for those that work with the NEx000 cards. > > Again, I'm not certain, but I believe that access to the buffer does not > > take place via a memory window at all. > > I was reading from the comments in the /sys/i386/isa/if_ed.c. Search > for the string "mem_end". > > I think you might be looking at the 3COM specific code? No, the 3com cards have (optional) shared memory, which IIRC is required. Regardless, mem_{start|end|size} are the correct numbers to work with, they describe the internal configuration of the card. > Terry Lambert -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] Collector of old Unix hardware. "Where are your PEZ?" The Tick [[
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