Mail Archives: djgpp/1994/03/21/09:28:31
I need a little help getting a high resolution timer working under DJGPP.
I have some real mode source for setting timers (timer 0 and timer 2), and
also have played around with the timer.c source in samples\dpmi. In the
real mode code, they crank up timer 0 and call the original handler at
the same old 18.whatever frequency. I would like to do the same under
DJGPP. By doing an outportb(0x43,0x36) outportb(0x40,low) outportb(0x40,hi),
I have been able to increase the timer's speed, however, the system clock
advances far too much because I am chaining the interrupt.
If I try to use the set_protected_mode_interrupt instead of the
chain_interrupt, my routine gets called only once (I preserve all registers,
and return with an IRET). Must I somehow signify that I am done and the
interrupt was a success? The real mode code had to read the value at
address 0x20 and then outport it back again.
Can I set up timer 2? Does it exist in protected mode?
Has anyone written routines under djgpp for communicating with the MIDI
port on a soundblaster?
Thank you,
Erik Johnson
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