2020-09-30 17:12:29 +02:00

146 lines
3.8 KiB
ArmAsm

/***********************************************************************
Copyright 1994 MOTOROLA, INC. All Rights Reserved. This file
contains copyrighted material. Use of this file is restricted
by the provisions of a Motorola Software License Agreement.
File Name:
PXCLKSUP.S
Globals:
none
Functions:
HalpUpdateDecrementer
KeQueryPerformanceCounter
History:
11-Feb-1994 Steve Johns
Original Version
23-Jun-1994 Steve Johns (sjohns@pets.sps.mot.com)
Fixed HalpZeroPerformanceCounter. Was writing to RTCU & RTCL.
Writes should go to SPR 20 & 21.
11-Sep-1995 Steve Johns
Removed 601 specific code
Removed 603 workaround, since we don't support < 603 v3.2
***********************************************************************/
#include <halppc.h>
#define ERRATA603 FALSE
LEAF_ENTRY(HalpSetDecrementer)
mtdec r.3 // Set the DECREMENTER
LEAF_EXIT(HalpSetDecrementer)
LEAF_ENTRY(HalpUpdateDecrementer)
//
// Read the DECREMENTER to get the interrupt latency and bias Count by
// that amount. Otherwise, the latencies would accumulate and the time
// of day would run slow.
//
mfdec r.7 // Read the DECREMENTER
add r.4,r.3,r.7 // + Count
//
// We expect that the DECREMENTER should be near 0xFFFFFFxx, so R4 should
// be less than r.3. If not, we don't want to cause an excessively long
// clock tick, so just ignore the latency and use Count.
//
cmpl 0,0,r.4,r.3
ble SetDecr
mr r.4,r.3
SetDecr:
mtdec r.4 // Write to the DECREMENTER
#if ERRATA603
isync
#endif
// Undocumented return value: the latency in servicing this interrupt
neg r.3,r.7
LEAF_EXIT(HalpUpdateDecrementer)
.extern HalpPerformanceFrequency
/***********************************************************************
Synopsis:
ULARGE_INTEGER KeQueryPerformanceCounter (
OUT PLARGE_INTEGER PerformanceFrequency OPTIONAL)
Purpose:
Supplies a 64-bit realtime counter for use in evaluating performance
of routines.
Returns:
This routine returns current 64-bit performance counter and,
optionally, the frequency of the Performance Counter.
Global Variables Referenced:
HalpPerformanceFrequency
***********************************************************************/
//
// Register Definitions
//
.set RetPtr, r.3
.set Freq, r.4
.set TimerLo, r.6
.set TimerHi, r.7
.set Temp, r.8
LEAF_ENTRY(KeQueryPerformanceCounter)
cmpli 0,0,Freq,0 // Was PerformanceFrequency passed ?
beq ReadTB
lwz Temp,[toc]HalpPerformanceFrequency(r.toc)
lwz Temp,0(Temp) // PerformanceFrequency.LowPart =
stw Temp,0(Freq) // HalpPerformanceFrequency;
li Temp,0 // PerformanceFrequency.HighPart = 0;
stw Temp,4(Freq)
ReadTB:
mftbu TimerHi // Read the TB registers coherently
mftb TimerLo
#if ERRATA603
mftb TimerLo
mftb TimerLo
mftb TimerLo
#endif
mftbu Temp
cmpl 0,0,Temp,TimerHi
bne- ReadTB
stw TimerLo,0(RetPtr)
stw TimerHi,4(RetPtr)
LEAF_EXIT(KeQueryPerformanceCounter)
.set TB, 284
.set TBU, 285
LEAF_ENTRY(HalpZeroPerformanceCounter)
li r.3, 0
mtspr TB,r.3
mtspr TBU,r.3
LEAF_EXIT(HalpZeroPerformanceCounter)