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From: feustel@netcom.UUCP (David Feustel)
Newsgroups: comp.arch
Subject: Re: Interrupts in user space; Lightweight Traps
Message-ID: <14065@netcom.UUCP>
Date: 29 Sep 90 00:01:35 GMT
References: <70576@sgi.sgi.com> <12824@encore.Encore.COM>
Organization: DAFCO - An OS/2 Oasis
Lines: 9

These traps could be simply implemented in the Intel 80586 by
implementing a software interrupt bit vector similar to the io port
permission bitmap that already exists on the 386 and 486. If the sw
int bit is clear, control goes to the system when the corresponding
sw int instruction is executed. Otherwise index into the first 256
pointers in low memory in the user task to get the address of the
routine to be called.
-- 
David Feustel, 1930 Curdes Ave, Fort Wayne, IN 46805, (219) 482-9631