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Article #4Re: Fixed point multiplication on 386
From: Tom Griest
Date: Tue, 27 Oct 1992 22:42
Date: Tue, 27 Oct 1992 22:42
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In article <1992Oct27.131559.14019@rz.uni-jena.de> pfk@rz.uni-jena.de (Frank Klemm) writes: > > >|> If you are in a multi-tasking >|> system, the kernel may not save and restore the high 16-bits of >|> the registers. In this case you should disable interrupts during >|> the multiplication.) > MS-DOS is not a preemptive kernel so there is no problem unless you have an interrupt routine which performs 32-bit operations and it can potentially interrupt other user code which is also performing 32-bit operations. Unless you write the interrupt routine to save and restore the 32-bit registers, you can get into trouble. For example, if you have the timer interrupt call-out invoke some 32-bit code, this will most likely corrupt other 32-bit code that is executing at the time the timer interrupt occurs.
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Newsgroups: comp.sys.intel Path: arc1-ca.pugleaf.net!sparky!uunet!charon.amdahl.com!pacbell.com!sgiblab!sdd.hp.com!think.com!ames!agate!usenet.ins.cwru.edu!magnus.acs.ohio-state.edu!cis.ohio-state.edu!news.sei.cmu.edu!ajpo.sei.cmu.edu!griest From: griest@ajpo.sei.cmu.edu (Tom Griest) Subject: Re: Fixed point multiplication on 386 Message-ID: <1992Oct27.224257.13707@sei.cmu.edu> Sender: netnews@sei.cmu.edu (Netnews) Organization: Ada Joint Program Office References: <5645@ssc-bee.ssc-vax.boeing.com> <1992Oct23.134617.21827@sei.cmu.edu> <1992Oct27.131559.14019@rz.uni-jena.de> Date: Tue, 27 Oct 1992 22:42:57 GMT Lines: 17