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- Fixed the timer calibration for processors without a tsc, spotted by Casper Hornstrup.

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svn path=/trunk/; revision=12189
This commit is contained in:
Hartmut Birr 2004-12-18 18:04:18 +00:00
parent 4bd03f70f7
commit d7be13618b
1 changed files with 19 additions and 21 deletions
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28
reactos/hal/halx86/generic/timer.c
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@ -20,7 +20,7 @@
* MA 02139, USA. * MA 02139, USA.
* *
*/ */
/* $Id: timer.c,v 1.1 2004/12/03 20:10:43 gvg Exp $ /* $Id: timer.c,v 1.2 2004/12/18 18:04:18 hbirr Exp $
* *
* PROJECT: ReactOS kernel * PROJECT: ReactOS kernel
* FILE: ntoskrnl/hal/x86/udelay.c * FILE: ntoskrnl/hal/x86/udelay.c
@ -41,8 +41,6 @@
/* GLOBALS ******************************************************************/ /* GLOBALS ******************************************************************/
static unsigned int delay_count = 1;
#define TMR_CTRL 0x43 /* I/O for control */ #define TMR_CTRL 0x43 /* I/O for control */
#define TMR_CNT0 0x40 /* I/O for counter 0 */ #define TMR_CNT0 0x40 /* I/O for counter 0 */
#define TMR_CNT1 0x41 /* I/O for counter 1 */ #define TMR_CNT1 0x41 /* I/O for counter 1 */
@ -232,26 +230,26 @@ VOID HalpCalibrateStallExecution(VOID)
WaitFor8254Wraparound(); WaitFor8254Wraparound();
delay_count = 1; Pcr->StallScaleFactor = 1;
do do
{ {
delay_count <<= 1; /* Next delay count to try */ Pcr->StallScaleFactor <<= 1; /* Next delay count to try */
WaitFor8254Wraparound(); WaitFor8254Wraparound();
__KeStallExecutionProcessor(delay_count); /* Do the delay */ __KeStallExecutionProcessor(Pcr->StallScaleFactor); /* Do the delay */
CurCount = Read8254Timer(); CurCount = Read8254Timer();
} }
while (CurCount > LATCH / 2); while (CurCount > LATCH / 2);
delay_count >>= 1; /* Get bottom value for delay */ Pcr->StallScaleFactor >>= 1; /* Get bottom value for delay */
/* Stage 2: Fine calibration */ /* Stage 2: Fine calibration */
DbgPrint("delay_count: %d", delay_count); DbgPrint("delay_count: %d", Pcr->StallScaleFactor);
calib_bit = delay_count; /* Which bit are we going to test */ calib_bit = Pcr->StallScaleFactor; /* Which bit are we going to test */
for (i = 0; i < PRECISION; i++) for (i = 0; i < PRECISION; i++)
{ {
@ -261,26 +259,26 @@ VOID HalpCalibrateStallExecution(VOID)
break; /* If we have done all bits, stop */ break; /* If we have done all bits, stop */
} }
delay_count |= calib_bit; /* Set the bit in delay_count */ Pcr->StallScaleFactor |= calib_bit; /* Set the bit in delay_count */
WaitFor8254Wraparound(); WaitFor8254Wraparound();
__KeStallExecutionProcessor(delay_count); /* Do the delay */ __KeStallExecutionProcessor(Pcr->StallScaleFactor); /* Do the delay */
CurCount = Read8254Timer(); CurCount = Read8254Timer();
if (CurCount <= LATCH / 2) /* If a tick has passed, turn the */ if (CurCount <= LATCH / 2) /* If a tick has passed, turn the */
{ /* calibrated bit back off */ { /* calibrated bit back off */
delay_count &= ~calib_bit; Pcr->StallScaleFactor &= ~calib_bit;
} }
} }
/* We're finished: Do the finishing touches */ /* We're finished: Do the finishing touches */
delay_count /= (MILLISEC / 2); /* Calculate delay_count for 1ms */ Pcr->StallScaleFactor /= (MILLISEC / 2); /* Calculate delay_count for 1ms */
DbgPrint("]\n"); DbgPrint("]\n");
DbgPrint("delay_count: %d\n", delay_count); DbgPrint("delay_count: %d\n", Pcr->StallScaleFactor);
DbgPrint("CPU speed: %d\n", delay_count / 250); DbgPrint("CPU speed: %d\n", Pcr->StallScaleFactor / 250);
#if 0 #if 0
DbgPrint("About to start delay loop test\n"); DbgPrint("About to start delay loop test\n");
DbgPrint("Waiting for five minutes..."); DbgPrint("Waiting for five minutes...");