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From: tabu6@CCVAX.IASTATE.EDU (Adam Goldberg)
Newsgroups: comp.os.msdos.programmer,comp.os.os2.programmer
Subject: Re: Info on Changing Stacks in protected mode
Message-ID: <1991Mar30.164216.5871@news.iastate.edu>
Date: 30 Mar 91 16:42:16 GMT
References: <1991Mar29.155840.2626@netcom.COM>,<1991Mar29.183850.27619@unicorn.cc.wwu.edu>
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In article <1991Mar29.183850.27619@unicorn.cc.wwu.edu>, kevinj@unicorn.cc.wwu.edu (Kevin Johnson) writes:
>resnicks@netcom.COM (Steve Resnick) writes:
>>OS/2 will not let me clear interrupts while changing SS:SP.  My question:
>>Is it necessary to disable interrupts while switching stacks in protected 
>>mode? 
>
>I always thought it was necessary, and that's how I do it.  Of course, I'm
>not an expert on the issue.

As part of the hardware in the 80x86 series, interrupts are disabled for
exactly one instruction after loading the SS, in order for you to load the SP. 
You need not do it yourself in protected mode or otherwise--Intel has already
done it for you, and its built into the processor.


+----------------------------------------------------------------------------+
+ Adam Goldberg                         Bitnet:   tabu6@ISUVAX.BITNET        +
+ Iowa State University                 Internet: tabu6@CCVAX.IASTATE.EDU    +
+          "It's simple!  Even a Pascal programmer could do it!"             +
+ "Remember: The sooner you fall behind, the more time you have to catch up" +
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