Xref:	news2.mv.net comp.os.msdos.djgpp:6129
From:	snarfy AT goodnet DOT com
Newsgroups:	comp.os.msdos.djgpp
Subject:	preemptive multitasking for dj
Date:	18 Jul 1996 21:39:30 GMT
Organization:	GoodNet
Lines:	19
Message-ID:	<4smaui$1jm@news.goodnet.com>
NNTP-Posting-Host:	goodnet.com
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

I've been working on a preemptive multitasking library and I've finally
gotten it to work.  The only problem is that the task-switching is slow.
I'm hooking IRQ0 with the default 18.2 tick/sec.  I've speeded up the 
timer to about 400hz without problems, but anything above that explodes.
400hz task switching would be fine with me except that I want to hook
IRQ8 so that my tasks will be compatible with most other libraries (most
people use IRQ0 as a timer in their libs.).  The problem is that IRQ8 
interrupts at 1024hz and is not adjustable.  I also have to use 
_go32_dpmi_chain... to hook IRQ8.  The standard __dpmi doesn't seem
to hook IRQ8 unless I chain it.  The __dpmi functions do work with IRQ0.

If anybody wants to help me out with this, feel free!  I'll send you
source if you mail me (there's too much to post here.).  I've a strong
suspision that my interrupt code is what's at fault.


Josh
snarfy AT goodnet DOT com

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