www.delorie.com/archives/browse.cgi | search |
Xref: | news-dnh.mv.net comp.os.msdos.djgpp:1447 |
Path: | news-dnh.mv.net!mv!news.sprintlink.net!newsfeed.internetmci.com!news.msfc.nasa.gov!bcm.tmc.edu!newsfeed.rice.edu!rice!news!sandmann |
From: | Charles Sandmann <sandmann AT clio DOT rice DOT edu> |
Newsgroups: | comp.os.msdos.djgpp |
Subject: | Re: CLI asm instruction |
Date: | Tue, 08 Aug 1995 20:23:44 CDT |
Organization: | Rice University, Houston, Texas |
Lines: | 12 |
References: | <DCzGMs DOT Ius AT jade DOT mv DOT net> <302779a0 DOT sandmann AT clio DOT rice DOT edu> <408or5$bk0 AT st-james DOT comp DOT vuw DOT ac DOT nz> |
Reply-To: | sandmann AT clio DOT rice DOT edu |
Nntp-Posting-Host: | clio.rice.edu |
To: | djgpp AT sun DOT soe DOT clarkson DOT edu |
Dj-Gateway: | from newsgroup comp.os.msdos.djgpp |
> If CLI is so slow then how are interrupts disabled inside interrupt > routines normally? Or do they just take the performance hit. Interrupt routines in PM are by nature slow, since they almost always involve a ring change, a stack change, and usually a change to RM and back. The interrupt flag gets cleared during all of the ring 0 processing, instead of being handled in an exception, so doesn't add anything there. But CLI is only slow if the DPMI runs occasionally at IOPL != CPL, which multitasking OS's would do. If the DPMI always runs as IOPL == 3 (like CWSDPMI) then you always get direct access to the flag and you can wedge the machine at will ...
webmaster | delorie software privacy |
Copyright © 2019 by DJ Delorie | Updated Jul 2019 |