Re: asm.e questions
Can anybody tell me if I need to enter real mode using the method described
below in order to use INT #21 file operations from 32-bit assembly?
Bernie Ryan wrote:
> I don't know what you mean by not using the dos interrupt because
> int 21 is the dos interrupt?
I mean not using the Euphoria dos_interrupt() function, which I assume provides
some insulation from protected/real mode problems and of course is inaccesible
from within an interrupt service routine.
>
> If you mean to call real mode from protected mode you can use causeway
> interrupt 31 FF01 ( INTXX ) or FF02 ( FARCALLREAL ). See Ralph Brown's
> intterupt list for details.
I would first like to know if this is strictly necessary for file handle based
dos operations before writing mountains of unneeded assembly. Is it the case?
> You may be interested in looking at
> Jacques Deschenes doswrap.e that has code for block reads and writes.
> Jacques Deschenes also has a file for cdaudio that uses real mode calls
> in the the RMCALL.E. Jacques has alot of good code in the archive.
>
> Also his code may give you ideas about using the segments.
>
I have studied the doswrap.e code, but it is based on the dos_interrupt()
function and reveals nothing more than what's already in my old book on
assembly. I will have a closer look at rmcall.e and Ralf's list and hope they
provide some new insights.
>
> PS Have you ever considered writing a TSR or Driver that you load and
> call from Euphoria with software interrupts.
I did consider this, and it would probably be a better environment for coding
this kind of thing, but I would prefer a neat, readable and especially hackable
include file for all Euphorians to use. A TSR system would have just the
wrapper and some inacessable com or exe file that must be loaded and unloaded
seperately.
Thanks all,
--
Nick Metcalfe <metcalfn at alphalink.com.au>
http://www.alphalink.com.au/~metcalfn
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