[fpc-pascal] simple sound implementation

Mark Wood mark at timeandmotion.com.au
Mon Sep 3 17:17:05 CEST 2007

True. And at least some of us have now upgraded to Sound Blaster!  :-D


Daniël Mantione wrote:
> Op Sun, 2 Sep 2007, schreef Mark Wood:
>>> Naturally, this is not possible: The PC speaker is simply controlled by a
>>> timer, which creates a square wave (on/off). In ancient DOS times there
>>> was a trick by doing a frequency modulation, i.e. you turn the timer on
>>> and off quite fast. But on Linux etc. the drivers don't support such
>>> cheats.
>> <scratches chin> Hmmm... could you use that old Turbo Pascal code to do an
>> inline of the ASM for it? (talking completely through my hat having never
>> attempted such a thing on a linux platform)
> If you run as root, acquire I/O port access and run SCHED_FIFO (so you are 
> not pre-empted), it might work.
> However, as nowadays all PCs have a 16 bit audio possibility I don't see a 
> reason to do such ugly tricks with the PC speaker.
> Daniël
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