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103 lines
1.8 KiB
103 lines
1.8 KiB
// TITLE("Manipulate Interrupt Request Level")
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//++
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//
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// Copyright (c) 1990 Microsoft Corporation
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// Copyright (c) 1992 Microsoft Corporation
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//
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// Module Name:
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//
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// irql.s
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//
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// Abstract:
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//
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// This module implements the code necessary to lower and raise the current
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// Interrupt Request Level (IRQL).
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//
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//
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// Author:
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//
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// David N. Cutler (davec) 12-Aug-1990
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// Joe Notarangelo 06-Apr-1992
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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 "ksalpha.h"
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//++
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//
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// VOID
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// KeLowerIrql (
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// KIRQL NewIrql
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// )
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//
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// Routine Description:
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//
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// This function lowers the current IRQL to the specified value.
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//
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// Arguments:
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//
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// NewIrql (a0) - Supplies the new 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(KeLowerIrql)
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SWAP_IRQL // a0 = new, on return v0 = old irql
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ret zero, (ra) // return
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.end KeLowerIrql
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//++
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//
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// VOID
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// KeRaiseIrql (
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// KIRQL NewIrql,
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// 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 the specified value and returns
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// the old IRQL value.
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//
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// Arguments:
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//
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// NewIrql (a0) - Supplies the new IRQL value.
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//
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// OldIrql (a1) - Supplies a pointer to a variable that recieves the old
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// 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(KeRaiseIrql)
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bis a1, zero, t0 // save pointer to old irql
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SWAP_IRQL // a0 = new, on return v0 = old irql
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ldq_u t1, 0(t0) // get quadword around old irql
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bic t0, 0x3, t3 // get containing longword address
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insbl v0, t0, t2 // put destination byte into position
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mskbl t1, t0, t1 // clear destination byte
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bis t1, t2, t1 // merge destination byte
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extll t1, t3, t1 // get appropriate longword
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stl t1, 0(t3) // store byte
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ret zero, (ra) // return
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.end KeRaiseIrql
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