OpenEuphoria

Re: asm.e questions

• Posted by Robert Craig <rds at ATTCANADA.NET> Oct 22, 1999
• 555 views

Bernie Ryan writes:
> 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 interrupt list for details.

Euphoria's dos_interrupt() uses CauseWay
interrupt 31 with AX=FF01. Jacques seems to use
some other method in his rmcall.e. Ralf Brown's
description of FF01 is rather skimpy.
My CauseWay printed manual has a lot more detail on it.

Nick Metcalfe writes:
> 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?

I'm pretty sure that you must switch into real mode
before doing any DOS interrupts. DOS is totally
16-bit based.

The idea of doing file operations while in the middle of
handling a hardware interrupt, sounds pretty scary.
Maybe you should store some information in memory,
return from the interrupt, then do the file operations
at your leisure, outside of the interrupt handler.

Regards,
     Rob Craig
     Rapid Deployment Software
     http://www.RapidEuphoria.com