🚀 go-pugleaf

rmich@Lise.Unit.NO (Rolf Michelsen) writes:

> 
> I have a problem with TAMS version 2.0. Has anybody tried to use
> segment overrides in any of the string instructions?? I am trying
> to move data from ES:SI to ES:DI with REP MOVS [byte es:si],[di] but 
> did it work? NO :-( As far as I know it is possible to use segment

Segment overrides are indeed allowed with MOVS, and if you can't figure 
out how to get it on one line, you can use two lines:
 
  seges
  rep movsb
 
Unfortunately, using a segment override with a rep prefix, while legal, is 
not a good idea. On the 8086, if an interrupt occurs, the 8086 forgets 
about one of the prefixes-- the REP prefix, I think. So what happens is 
the interrupt service routine executes, returns to the string move, and 
thinks its done (CX is nonzero). This is fixed on the 80386, and I'm not 
sure about the 80286.


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