Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!oliveb!amiga!boing!dale
From: dale@boing.UUCP (Dale Luck)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Exec's use of the user stack for a task
Message-ID: <530@boing.UUCP>
Date: 20 Dec 88 00:29:26 GMT
References: <8812180904.AA24272@postgres.Berkeley.EDU>
Reply-To: dale@boing.UUCP (Dale Luck)
Organization: Boing, Milpitas, Ca.
Lines: 23

In article <8812180904.AA24272@postgres.Berkeley.EDU> dillon@POSTGRES.BERKELEY.EDU (Matt Dillon) writes:
>processes.  The stack pointer, A7, must at all times be pointing to at 
>least (around) 96 bytes of storage below it because EXEC does indeed push
>all the registers, PC, and condition codes onto it when switching between
>tasks.

You better give yourself a little extra if you ever use ieee libraries.
The state of the 68881 requires atleast an extra 150 bytes.

>
>	Not to begrudge EXEC.  All in all EXEC has only 4 or 5 incorrectly
>implemented items (use of the user stack, exceptions, lack of dynamic

You are right, addtask should allocate the stack space it needed to do
a proper task swap. This way we could up if necessary.

>
>					-Matt


-- 
Dale Luck     GfxBase/Boing, Inc.
{uunet!cbmvax|pyramid}!amiga!boing!dale