Re: MiNT context switching

[Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>]

Stephan Haslbeck <haslbecs@informatik.tu-muenchen.de> writes:

|> Hi all!
|> Maybe you know that MiNT doesn't switch contexts when a program is in
|> supervisor mode. It also doesn't when the flock (floppy locking) variable
|> is set - so I wonder why is this so?

Because the XBIOS floppy driver just set the flock variable without
paying attention if it is already set or not.  The XBIOS assumes that
the floppy is always free when it tries to access the floppy.  Only
the VBL interrupt looks at flock and skips the floppy controller
access if it is set.  The same often applies to the ACSI driver.

That means that only when the XBIOS floppy routines are completely
replaced and the flock variable is fully respected, both in the floppy
and the ACSI driver, MiNT can switch context when flock is set.

-- 
Andreas Schwab                                      "And now for something
schwab@issan.informatik.uni-dortmund.de              completely different"