///////////////////////////////////////////////////////////////////////////
//
// SDL_InitDelay() - Sets up TimerDelay's for SDL_Delay()
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_InitDelay(void)
{
id0_int_t i;
id0_word_t timer,speed;
setvect(8,SDL_TimingService); // Set to my timer 0 ISR
SDL_SetIntsPerSec(1000); // Time 1ms
for (i = 0,timer = 0;i < 10;i++) // Do timing test 10 times
{
asm xor dx,dx // Zero DX
asm mov cx,0xffff // Put starting value in CX
asm mov [TimerDone],cx // TimerDone = false - 1
startloop:
asm or [TimerDone],0
asm jnz startloop // Make sure we're at the start
loop:
asm test [TimerDone],1 // See if TimerDone flag got hit
asm jnz done // Yep - drop out of the loop
asm loop loop
done:
if (0xffff - TimerVal > timer)
timer = 0xffff - TimerVal;
}
timer += timer / 2; // Use some slop
TimerDelay10 = timer / (1000 / 10);
TimerDelay25 = timer / (1000 / 25);
TimerDelay100 = timer / (1000 / 100);
SDL_SetTimer0(0); // Reset timer 0
setvect(8,t0OldService); // Set back to old ISR
}
///////////////////////////////////////////////////////////////////////////
//
// SDL_SetIntsPerSec() - Uses SDL_SetTimer0() to set the number of
// interrupts generated by system timer 0 per second
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_SetIntsPerSec(word ints)
{
SDL_SetTimer0(1192030 / ints);
}
///////////////////////////////////////////////////////////////////////////
//
// SDL_SetIntsPerSec() - Uses SDL_SetTimer0() to set the number of
// interrupts generated by system timer 0 per second
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_SetIntsPerSec(id0_word_t ints)
{
SDL_SetTimer0(1192755 / ints);
}
///////////////////////////////////////////////////////////////////////////
//
// SDL_SetIntsPerSec() - Uses SDL_SetTimer0() to set the number of
// interrupts generated by system timer 0 per second
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_SetIntsPerSec(word ints)
{
TimerRate = ints;
SDL_SetTimer0(1192030 / ints);
}
