The DMA controller, the programmable interrupt controller and the counter
timer integrated peripherals in an 8018x CPU are at completely different
addresses from the addresses of their counterparts in a PC. Unless you
ignored them or accepted the discrepancies, it wouldn't be compatible enough
for most uses.
Norm
> -----Original Message-----
> From: David Olofson [SMTP:[EMAIL PROTECTED]]
> Sent: Wednesday, July 12, 2000 3:58 PM
> To: Norm Dresner; Andrew Tuckey; [EMAIL PROTECTED]
> Subject: [rtl] Re: Context Switching Speed - DMA.
>
> Tue, 11 Jul 2000 Norm Dresner wrote:
> > At 05:14 PM 7/11/2000 +0200, David Olofson wrote:
> > >Sat, 08 Jul 2000 Andrew Tuckey wrote:
> > >[...]
> >
> > >x86 doesn't have DMA on the chip (*), but uses either the 8 DMA
> channels
> > on the
> > >mainboard chipset (4 x 8 bit + 4 x 16 bit; normally used with ISA
> boards)
> > or PCI
> > >busmaster DMA, which is supported by the PCI chipset but performed by
> the PCI
> > >cards themselves. AGP is quite similar to PCI in this respect, AFAIK.
> > >
> > >(*) exception: some x86 clones for embedded systems, with some standard
> > > chipset functionality included.
> > >
> >
> > That's not quite correct: The Intel 80186/80188 had integrated DMA.
>
> Yeah, I forget the 8018x! :-) IIRC, it was never user in a PC, but in
> varios
> computer peripherals.
>
> > What is (closer to being) correct is that no "PC's" were produced with
> an
> > x86 CPU with integrated DMA --
>
> I'm not so sure about that... There are these micro-AT integrated main
> boards
> with all sorts of weird chips on them. I cant't remember seeing one with
> an
> "MCU x86", but I wouldn't be surprized if they exist.
>
> > indeed it could be argued that if a computer
> > had integrated DMA, then it wasn't a PC-work-alike and hence not a "PC".
>
> Disregarding that the chipset would look different, a PC with such a CPU
> could
> still work like a PC, provided the DMA controller is compatible with that
> PC
> standard thing. (Not that I would want to see that on any new
> hardware...!)
>
>
> David Olofson
> Programmer
> Reologica Instruments AB
> [EMAIL PROTECTED]
>
> ..- M u C o S --------------------------------. .- David Olofson ------.
> | A Free/Open Multimedia | | Audio Hacker |
> | Plugin and Integration Standard | | Linux Advocate |
> `------------> http://www.linuxdj.com/mucos -' | Open Source Advocate |
> ..- A u d i a l i t y ------------------------. | Singer |
> | Rock Solid Low Latency Signal Processing | | Songwriter |
> `---> http://www.angelfire.com/or/audiality -' `-> [EMAIL PROTECTED] -'
> -- [rtl] ---
> To unsubscribe:
> echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
> echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
> ---
> For more information on Real-Time Linux see:
> http://www.rtlinux.org/rtlinux/
-- [rtl] ---
To unsubscribe:
echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
---
For more information on Real-Time Linux see:
http://www.rtlinux.org/rtlinux/
