[fpc-devel] M68k: important milestone reached

Michael Schnell mschnell at lumino.de
Tue Feb 25 09:30:41 CET 2014


This in many cases is not a problem, as the result shows either the 
state before or after the interrupt and so the atomic variable itself is 
not a problem.

Of course the user code needs to take into account that the result 
already might be changed in the Pascal instruction. But I thinks this is 
obvious, anyway.

To do a semaphore the state of which might be critical to be known at a 
certain point you can do something like

  bclr #0, (A0)
  move ccr, D0

here the inverted state of the bit before the operation will be in bit 2 
of D0.

-Michael




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