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From: mlake@irscscm.UUCP (Marshall Lake)
Newsgroups: comp.sys.atari.st.tech
Subject: The movep instruction & a strange display
Message-ID: <1990Oct31.155603.4066@irscscm.UUCP>
Date: 31 Oct 90 15:56:03 GMT
Reply-To: mlake@irscscm.UUCP (Marshall Lake)
Organization: Internal Revenue Service, Washington, DC
Lines: 22


Greetings everyone.

I am having a problem with a 68000 program where the screen goes
kaflooey at a certain point.  I'm not fooling with the screen in my
code, only the MFP and the sound chip.  The program works ok except for
the fact that it screws the display.  I've traced the cause of the
problem down to a movep instruction that occurs during a timer A
interrupt.  The movep is a weird instruction where it moves every other
segment (depending upon the mode) of the source to the destination.  Is
it possible that my assemblers (the only ones I have are MADMAC and the
MWC assembler, the latter being a real trip of an assembler) do not
handle the movep instruction correctly?  The same thing happens with
both of the assemblers.  I've seen the same code in other programs that
work properly.

I'm open to any and all explanations and/or suggestions.  Thanks.

-- 
Marshall Lake
mlake@irscscm.UUCP
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