Xref:	news-dnh.mv.net comp.os.msdos.djgpp:2624
Newsgroups:	comp.os.msdos.djgpp
Path:	news-dnh.mv.net!mv!news.sprintlink.net!cs.utexas.edu!bcm.tmc.edu!news.msfc.nasa.gov!newsfeed.internetmci.com!elvis.delphi.com!uunet!in1.uu.net!psinntp!psinntp!psinntp!psinntp!netrixgw.netrix.com!root
From:	ld AT jasmine DOT netrix DOT com (Long Doan)
Subject:	Re: [Q] ISR - Stack switching
Lines:	51
Sender:	root AT netrix DOT com
Organization:	Netrix Corporation
References:	<813408666 DOT 180snx AT techm DOT pl DOT my>
Date:	Fri, 13 Oct 1995 14:51:26 GMT
To:	djgpp AT sun DOT soe DOT clarkson DOT edu
Dj-Gateway:	from newsgroup comp.os.msdos.djgpp

In article <813408666 DOT 180snx AT techm DOT pl DOT my> kenfoo AT techm DOT pl DOT my (Kenneth Foo) writes:

> Question.
> How do we switch stacks in an interrupt service routine?

Some sample of code:
    asm ("
/*--------------------------------------------------------------------
    Switch stack.
--------------------------------------------------------------------*/
    pushl %eax
    pushl %ebx
    movl  %esp, %eax
    movw  %ss,  %bx
    pushl %ds
    popl  %ss
    movl  _My_isr_stack_end, %esp
    pushl $0
    pushl %eax
    pushl %ebx

/*--------------------------------------------------------------------
    Do whatever is necessary here
--------------------------------------------------------------------*/
    call  _my_big_interrupt_service_routine

/*--------------------------------------------------------------------
    Switch stack back.
--------------------------------------------------------------------*/
    popl  %ebx
    popl  %eax
    movw  %bx, %ss
    movl  %eax, %esp
    popl  %ebx
    popl  %eax
    ");

> Must %esp be doubleword (4-byte) aligned?

Yep.

Hope that helps,
Long.

-- 
==============================================================
Long Doan                                        ld AT netrix DOT com     
Netrix Corporation                         ldoan1 AT osf1 DOT gmu DOT edu
13595 Dulles Technology Drive                               
Herndon Va 22071
==============================================================

- Raw text -