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Re: 6502 Multitasking OS announce
- Subject: Re: 6502 Multitasking OS announce
- From: jponge@mtu.edu (Joshua P. Onge)
- Date: 1996/03/18
- Followup-to: comp.sys.cbm,comp.os.misc,alt.comp.hardware.homebuilt,comp.sys.apple2,comp.sys.apple2.programmer,comp.sys.atari.8bit
- Newsgroups: comp.sys.cbm, comp.os.misc, alt.comp.hardware.homebuilt, comp.sys.apple2, comp.sys.apple2.programmer, comp.sys.atari.8bit
- Organization: Michigan Technological University
- References: <4i94fs$stj@narses.hrz.tu-chemnitz.de> <holger.948.00030EE6@deep.hb.provi.de> <4ijtbe$7ca@no-names.nerdc.ufl.edu> <4ijuic$iiq@gatekeeper.liffe.com>
Ralph Mason (ralph.mason@liffe.com) wrote:
: Michael Ellis <michael@anest4.anest.ufl.edu> wrote:
: >holger@deep.hb.provi.de (Holger Bruns) wrote:
: >>An operating system for the 6502 should have some of the properties of CPM.
: >>Parameters could be passed into registers and some zeropage locations.
: > The way to get around this is to pass all parameters on the stack, and use separate
: > stacks for the separate tasks.
: All well & good BUT the 6502 does not have a relocatable stack pointer
: so your kinda left with a bit of a problem when it commes to
: multitasking, ie you cant give each process it's own stack without
: copying the whole stack ( maybe just to the current sp value? )during
: each context switch.
I believe that, from reading Andre's webpage on his OS, the operating
system saves registers, to keep each program in it's own little world. You
should read his description, it's quite ineresting.
josh