497 lines
14 KiB
ArmAsm
497 lines
14 KiB
ArmAsm
// TITLE("Spin Locks")
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//++
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//
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// Copyright (c) 1990 Microsoft Corporation
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//
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// Module Name:
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//
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// spinlock.s
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//
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// Abstract:
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//
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// This module implements the routines for acquiring and releasing
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// spin locks.
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//
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// Author:
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//
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// David N. Cutler (davec) 23-Mar-1990
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//
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// Environment:
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//
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// Kernel mode only.
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//
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// Revision History:
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//
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//--
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#include "ksmips.h"
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SBTTL("Initialize Executive Spin Lock")
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//++
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//
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// VOID
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// KeInitializeSpinLock (
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// IN PKSPIN_LOCK SpinLock
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// )
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//
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// Routine Description:
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//
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// This function initialzies an executive spin lock.
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//
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// Arguments:
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//
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// SpinLock (a0) - Supplies a pointer to a executive spinlock.
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//
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// Return Value:
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//
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// None.
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//
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//--
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LEAF_ENTRY(KeInitializeSpinLock)
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sw zero,0(a0) // clear spin lock value
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j ra // return
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.end KeInitializeSpinlock
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SBTTL("Acquire Executive Spin Lock")
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// VOID KeAcquireSpinLock (IN PKSPIN_LOCK SpinLock
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// OUT PKIRQL OldIrql)
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// Routine Description:
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// This function raises the current IRQL to DISPATCH_LEVEL and acquires the specified executive spinlock.
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// Arguments:
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// SpinLock (a0) - Supplies a pointer to a executive spinlock.
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// OldIrql (a1) - Supplies a pointer to a variable that receives the the previous IRQL value.
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// N.B. The Old IRQL MUST be stored after the lock is acquired.
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// Return Value:
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// None.
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LEAF_ENTRY(KeAcquireSpinLock)
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//
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// Disable interrupts and attempt to acquire the specified spinlock.
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//
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li a2,DISPATCH_LEVEL // set new IRQL level
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10: DISABLE_INTERRUPTS(t2) // disable interrupts
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#if !defined(NT_UP)
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lw t0,KiPcr + PcCurrentThread(zero) // get address of current thread
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20: ll t1,0(a0) // get current lock value
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move t3,t0 // set ownership value
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bne zero,t1,30f // if ne, spin lock owned
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sc t3,0(a0) // set spin lock owned
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beq zero,t3,20b // if eq, store conditional failure
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#endif
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//
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// Raise IRQL to DISPATCH_LEVEL and acquire the specified spinlock.
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//
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// N.B. The raise IRQL code is duplicated here to avoid any extra overhead
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// since this is such a common operation.
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//
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lbu t0,KiPcr + PcIrqlTable(a2) // get translation table entry value
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li t1,~(0xff << PSR_INTMASK) // get interrupt enable mask
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sll t0,t0,PSR_INTMASK // shift table entry into position
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lbu v0,KiPcr + PcCurrentIrql(zero) // get current IRQL
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and t2,t2,t1 // clear current interrupt enables
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or t2,t2,t0 // set new interrupt enables
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sb a2,KiPcr + PcCurrentIrql(zero) // set new IRQL
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ENABLE_INTERRUPTS(t2) // enable interrupts
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sb v0,0(a1) // store old IRQL
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j ra // return
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#if !defined(NT_UP)
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30: ENABLE_INTERRUPTS(t2) // enable interrupts
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b 10b // try again
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#endif
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.end KeAcquireSpinLock
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SBTTL("Acquire SpinLock and Raise to Dpc")
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// KIRQL KeAcquireSpinLockRaiseToDpc (IN PKSPIN_LOCK SpinLock)
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// Routine Description:
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// This function raises the current IRQL to dispatcher level and acquires the specified spinlock.
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// Arguments:
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// SpinLock (a0) - Supplies a pointer to the spinlock that is to be acquired.
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// Return Value:
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// The previous IRQL is returned at the fucntion value.
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LEAF_ENTRY(KiAcquireSpinLockRaiseIrql)
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ALTERNATE_ENTRY(KeAcquireSpinLockRaiseToDpc)
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li a1,DISPATCH_LEVEL // set new IRQL level
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b 10f // finish in common code
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SBTTL("Acquire SpinLock and Raise to Synch")
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// KIRQL KeAcquireSpinLockRaiseToSynch (IN PKSPIN_LOCK SpinLock)
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// Routine Description:
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// This function raises the current IRQL to synchronization level and acquires the specified spinlock.
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// Arguments:
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// SpinLock (a0) - Supplies a pointer to the spinlock that is to be acquired.
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// Return Value:
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// The previous IRQL is returned at the fucntion value.
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ALTERNATE_ENTRY(KeAcquireSpinLockRaiseToSynch)
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//
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// Disable interrupts and attempt to acquire the specified spinlock.
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//
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lbu a1,KiSynchIrql // set new IRQL level
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10: DISABLE_INTERRUPTS(t2) // disable interrupts
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#if !defined(NT_UP)
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lw t0,KiPcr + PcCurrentThread(zero) // get address of current thread
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20: ll t1,0(a0) // get current lock value
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move t3,t0 // set ownership value
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bne zero,t1,30f // if ne, spin lock owned
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sc t3,0(a0) // set spin lock owned
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beq zero,t3,20b // if eq, store conditional failure
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#endif
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//
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// Raise IRQL to synchronization level and acquire the specified spinlock.
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//
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// N.B. The raise IRQL code is duplicated here to avoid any extra overhead
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// since this is such a common operation.
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//
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lbu t0,KiPcr + PcIrqlTable(a1) // get translation table entry value
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li t1,~(0xff << PSR_INTMASK) // get interrupt enable mask
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sll t0,t0,PSR_INTMASK // shift table entry into position
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lbu v0,KiPcr + PcCurrentIrql(zero) // get current IRQL
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and t2,t2,t1 // clear current interrupt enables
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or t2,t2,t0 // set new interrupt enables
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sb a1,KiPcr + PcCurrentIrql(zero) // set new IRQL
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ENABLE_INTERRUPTS(t2) // enable interrupts
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j ra // return
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#if !defined(NT_UP)
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30: ENABLE_INTERRUPTS(t2) // enable interrupts
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b 10b // try again
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#endif
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.end KiAcquireSpinLockRaiseIrql
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SBTTL("Release Executive Spin Lock")
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//++
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//
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// VOID
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// KeReleaseSpinLock (
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// IN PKSPIN_LOCK SpinLock
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// IN KIRQL OldIrql
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// )
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//
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// Routine Description:
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//
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// This function releases an executive spin lock and lowers the IRQL
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// to its previous value.
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//
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// Arguments:
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//
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// SpinLock (a0) - Supplies a pointer to an executive spin lock.
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//
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// OldIrql (a1) - Supplies the previous IRQL value.
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//
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// Return Value:
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//
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// None.
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//
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//--
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LEAF_ENTRY(KeReleaseSpinLock)
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//
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// Release the specified spinlock.
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//
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#if !defined(NT_UP)
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sw zero,0(a0) // set spin lock not owned
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#endif
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//
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// Lower the IRQL to the specified level.
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//
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// N.B. The lower IRQL code is duplicated here is avoid any extra overhead
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// since this is such a common operation.
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//
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and a1,a1,0xff // isolate old IRQL
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lbu t0,KiPcr + PcIrqlTable(a1) // get translation table entry value
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li t1,~(0xff << PSR_INTMASK) // get interrupt enable mask
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sll t0,t0,PSR_INTMASK // shift table entry into position
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DISABLE_INTERRUPTS(t2) // disable interrupts
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and t2,t2,t1 // clear current interrupt enables
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or t2,t2,t0 // set new interrupt enables
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sb a1,KiPcr + PcCurrentIrql(zero) // set new IRQL
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ENABLE_INTERRUPTS(t2) // enable interrupts
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j ra // return
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.end KeReleaseSpinLock
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SBTTL("Try To Acquire Executive Spin Lock")
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//++
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//
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// BOOLEAN
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// KeTryToAcquireSpinLock (
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// IN PKSPIN_LOCK SpinLock
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// OUT PKIRQL OldIrql
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// )
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//
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// Routine Description:
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//
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// This function raises the current IRQL to DISPATCH_LEVEL and attempts
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// to acquires the specified executive spinlock. If the spinlock can be
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// acquired, then TRUE is returned. Otherwise, the IRQL is restored to
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// its previous value and FALSE is returned.
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//
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// Arguments:
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//
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// SpinLock (a0) - Supplies a pointer to a executive spinlock.
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//
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// OldIrql (a1) - Supplies a pointer to a variable that receives the
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// the previous IRQL value.
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//
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// N.B. The Old IRQL MUST be stored after the lock is acquired.
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//
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// Return Value:
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//
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// If the spin lock is acquired, then a value of TRUE is returned.
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// Otherwise, a value of FALSE is returned.
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//
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//--
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LEAF_ENTRY(KeTryToAcquireSpinLock)
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//
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// Raise IRQL to DISPATCH_LEVEL and try to acquire the specified spinlock.
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//
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// N.B. The raise IRQL code is duplicated here to avoid any extra overhead
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// since this is such a common operation.
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//
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li a2,DISPATCH_LEVEL // set new IRQL level
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lbu t0,KiPcr + PcIrqlTable(a2) // get translation table entry value
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li t1,~(0xff << PSR_INTMASK) // get interrupt enable mask
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sll t0,t0,PSR_INTMASK // shift table entry into position
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lbu t2,KiPcr + PcCurrentIrql(zero) // get current IRQL
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DISABLE_INTERRUPTS(t3) // disable interrupts
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and t3,t3,t1 // clear current interrupt enables
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or t3,t3,t0 // set new interrupt enables
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sb a2,KiPcr + PcCurrentIrql(zero) // set new IRQL
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ENABLE_INTERRUPTS(t3) // enable interrupts
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//
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// Try to acquire the specified spinlock.
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//
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#if !defined(NT_UP)
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lw t0,KiPcr + PcCurrentThread(zero) // get address of current thread
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10: ll t1,0(a0) // get current lock value
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move v0,t0 // set ownership value
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bne zero,t1,20f // if ne, spin lock owned
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sc v0,0(a0) // set spin lock owned
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beq zero,v0,10b // if eq, store conditional failure
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#else
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li v0,TRUE // set return value
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#endif
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//
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// The attempt to acquire the specified spin lock succeeded.
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//
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sb t2,0(a1) // store old IRQL
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j ra // return
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//
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// The attempt to acquire the specified spin lock failed. Lower IRQL to its
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// previous value and return FALSE.
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//
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// N.B. The lower IRQL code is duplicated here is avoid any extra overhead
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// since this is such a common operation.
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//
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#if !defined(NT_UP)
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20: lbu t0,KiPcr + PcIrqlTable(t2) // get translation table entry value
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li t1,~(0xff << PSR_INTMASK) // get interrupt enable mask
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sll t0,t0,PSR_INTMASK // shift table entry into position
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DISABLE_INTERRUPTS(t3) // disable interrupts
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and t3,t3,t1 // clear current interrupt enables
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or t3,t3,t0 // set new interrupt enables
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sb t2,KiPcr + PcCurrentIrql(zero) // set new IRQL
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ENABLE_INTERRUPTS(t3) // enable interrupts
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li v0,FALSE // set return value
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j ra // return
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#endif
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.end KeTryToAcquireSpinLock
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SBTTL("Acquire Kernel Spin Lock")
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//++
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//
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// KIRQL
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// KiAcquireSpinLock (
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// IN PKSPIN_LOCK SpinLock
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// )
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//
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// Routine Description:
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//
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// This function acquires a kernel spin lock.
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//
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// N.B. This function assumes that the current IRQL is set properly.
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//
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// Arguments:
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//
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// SpinLock (a0) - Supplies a pointer to a kernel spin lock.
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//
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// Return Value:
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//
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// None.
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//
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//--
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LEAF_ENTRY(KiAcquireSpinLock)
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ALTERNATE_ENTRY(KeAcquireSpinLockAtDpcLevel)
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#if !defined(NT_UP)
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lw t0,KiPcr + PcCurrentThread(zero) // get address of current thread
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10: ll t1,0(a0) // get current lock value
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move t2,t0 // set ownership value
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bne zero,t1,10b // if ne, spin lock owned
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sc t2,0(a0) // set spin lock owned
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beq zero,t2,10b // if eq, store conditional failure
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#endif
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j ra // return
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.end KiAcquireSpinLock
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SBTTL("Release Kernel Spin Lock")
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//++
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//
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// VOID
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// KiReleaseSpinLock (
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// IN PKSPIN_LOCK SpinLock
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// )
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//
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// Routine Description:
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//
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// This function releases a kernel spin lock.
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//
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// N.B. This function assumes that the current IRQL is set properly.
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//
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// Arguments:
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//
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// SpinLock (a0) - Supplies a pointer to an executive spin lock.
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//
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// Return Value:
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//
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// None.
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//
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//--
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LEAF_ENTRY(KiReleaseSpinLock)
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ALTERNATE_ENTRY(KeReleaseSpinLockFromDpcLevel)
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#if !defined(NT_UP)
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sw zero,0(a0) // set spin lock not owned
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#endif
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j ra // return
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.end KiReleaseSpinLock
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SBTTL("Try To Acquire Kernel Spin Lock")
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//++
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//
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// KIRQL
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// KiTryToAcquireSpinLock (
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// IN PKSPIN_LOCK SpinLock
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// )
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//
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// Routine Description:
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//
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// This function attempts to acquires the specified kernel spinlock. If
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// the spinlock can be acquired, then TRUE is returned. Otherwise, FALSE
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// is returned.
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//
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// N.B. This function assumes that the current IRQL is set properly.
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//
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// Arguments:
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//
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// SpinLock (a0) - Supplies a pointer to a kernel spin lock.
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//
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// Return Value:
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//
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// If the spin lock is acquired, then a value of TRUE is returned.
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// Otherwise, a value of FALSE is returned.
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//
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//--
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LEAF_ENTRY(KiTryToAcquireSpinLock)
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#if !defined(NT_UP)
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li v0,FALSE // assume attempt to acquire will fail
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lw t0,KiPcr + PcCurrentThread(zero) // get address of current thread
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10: ll t1,0(a0) // get current lock value
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move t2,t0 // set ownership value
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bne zero,t1,20f // if ne, spin lock owned
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sc t2,0(a0) // set spin lock owned
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beq zero,t2,10b // if eq, store conditional failure
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#endif
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li v0,TRUE // set return value
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20: j ra // return
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.end KiTryToAcquireSpinLock
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