Re: [AD] Bug in MMX linear_clear_to_color8 with asynchronous usage

[Eric Botcazou <ebotcazou@xxxxxxxxxx>]

> To me it is a 'bit' unclear if that retriction is applied to interrupts or
> just djgpp interrupts.

Allegro provides its own IRQ code, which has the big advantage that the 
interrupts are reentrants. The restriction applies to this code.

> In fact, it is applied to djgpp or every system? Since right now I am
> clueless :)

Here are the two complete relevant paragraphes:
"Under DOS it will constantly reprogram the clock to make sure they are all 
called at the correct times. Because they alter the low level timer chip 
settings, these routines should not be used together with other DOS timer 
functions like the djgpp uclock() routine. Moreover, the FPU state is not 
preserved across Allegro interrupts so you ought not to use floating point 
or MMX code inside timer interrupt handlers. 

Under other platforms, they are usually implemented using threads, which run 
parallel to the main thread. Therefore timer callbacks on such platforms 
will not block the main thread when called, so you may need to use 
appropriate synchronisation devices (eg. mutexes, semaphores, etc.) when 
accessing data that is shared by a callback and the main thread. (Currently 
Allegro does not provide such devices.)"

-- 
Eric Botcazou