Re: 6502 Multitasking OS announce

[Michael Ellis <michael@anest4.anest.ufl.edu>]

falstaff@xs4all.nl (Falstaff) wrote:
>jponge@mtu.edu (Joshua P. Onge) writes:
>
>>> 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.
>
>Yes, but Joshua is right.  Each process will need some amount of stackspace



Maybe I'm nit-picking, but I wrote:

>>> The way to get around this is to pass all parameters on the stack, and use separate
>>> stacks for the separate tasks.


-Michael Ellis