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Path: sserve!newshost.anu.edu.au!munnari.oz.au!constellation!convex!convex!cs.utexas.edu!uunet!spool.mu.edu!bloom-beacon.mit.edu!mcrcim.mcgill.edu!homer.cs.mcgill.ca!storm From: storm@cs.mcgill.ca (Marc WANDSCHNEIDER) Newsgroups: comp.os.386bsd.questions Subject: Re: [NetBSD] What is this in SYS.h? Date: 1 Nov 1993 03:21:15 GMT Organization: SOCS, McGill University, Montreal, Canada Lines: 33 Message-ID: <2b1vbc$3t7@homer.cs.mcgill.ca> References: <2avo6k$mlm@homer.cs.mcgill.ca> <4177@bigfoot.first.gmd.de> NNTP-Posting-Host: mnementh.cs.mcgill.ca X-ORIGINAL-NEWSGROUPS: comp.os.386bsd.questions,comp.os.386bsd.development In article <4177@bigfoot.first.gmd.de>, Andreas Schulz <ats@g386bsd.first.gmd.de> wrote: >An expanded call for this would look: >2: jmp cerror; >open: # Label for system call > lea SYS_open,%eax # put the number for the system call > # into the eax register > .byte 0x9a # trap into the kernel > .long 0 # these are arguments to the > .word 7 # trap. > > >I am not sure, if the 0x9a is a trap or a gate-call , for this you >must look into a 386 CPU description. I don't know, where mine is, >i try to prevent assembly programming on this type of CPU :-). It turns out that the 0x9a is the CALL instruction INTO a more privileged mode in a different segment. Discovered that by looking through the Intel i386 book one instruction at a time :-) Toodlepip! Marc 'em. -- ----------------------------------------------------------------------------- Marc Wandschneider Seattle, WA Barney the Dinosaur sings! You faint... Barney sings! Barney sings! --More-- You Die... --More--