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Changed it so pit counters count down and correct latching of mode 3 timers.

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@572
This commit is contained in:
Sjoerd van der Berg 2002-12-16 09:31:38 +00:00
parent 93ebf23a18
commit 6e61c2621a
1 changed files with 15 additions and 8 deletions
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23
src/hardware/timer.cpp
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@ -56,20 +56,26 @@ static void counter_latch(Bitu counter) {
/* Fill the read_latch of the selected counter with current count */
PIT_Block * p=&pit[counter];
Bit64s micro=PIC_MicroCount();
micro-=p->start;
micro%=p->micro;
Bit16u ticks=(Bit16u)(((float)micro/(float)p->micro)*(float)p->cntr);
Bit64s micro=PIC_MicroCount()-p->start;
switch (p->mode) {
case 0:
if (micro>p->micro) p->read_latch=p->write_latch;
else p->read_latch=(Bit16u)(p->cntr-(((float)micro/(float)p->micro)*(float)p->cntr));
break;
case 2:
micro%=p->micro;
p->read_latch=(Bit16u)(p->cntr-(((float)micro/(float)p->micro)*(float)p->cntr));
break;
case 3:
case 4:
p->read_latch=(Bit16u)ticks;
micro%=p->micro;
micro*=2;
if (micro>p->micro) micro-=p->micro;
p->read_latch=(Bit16u)(p->cntr-(((float)micro/(float)p->micro)*(float)p->cntr));
break;
default:
LOG_ERROR("PIT:Illegal Mode %d for reading counter %d",p->mode,counter);
p->read_latch=(Bit16u)ticks;
micro%=p->micro;
p->read_latch=(Bit16u)(p->cntr-(((float)micro/(float)p->micro)*(float)p->cntr));
break;
}
}
@ -106,6 +112,7 @@ static void write_latch(Bit32u port,Bit8u val) {
LOG_DEBUG("PIT 0 Timer at %.3g Hz mode %d",PIT_TICK_RATE/(double)p->cntr,p->mode);
break;
case 0x02: /* Timer hooked to PC-Speaker */
// LOG_DEBUG("PIT 2 Timer at %.3g Hz mode %d",PIT_TICK_RATE/(double)p->cntr,p->mode);
PCSPEAKER_SetCounter(p->cntr,p->mode);
break;
default: