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394 lines
11 KiB
394 lines
11 KiB
title "Critical Section Support"
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;++
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;
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; Copyright (c) 1991 Microsoft Corporation
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;
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; Module Name:
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;
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; critsect.asm
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;
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; Abstract:
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;
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; This module implements functions to support user mode critical sections.
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;
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; Author:
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;
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; Bryan M. Willman (bryanwi) 2-Oct-91
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;
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; Environment:
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;
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; Any mode.
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;
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; Revision History:
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;
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;--
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.486p
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.xlist
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include ks386.inc
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include callconv.inc ; calling convention macros
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include mac386.inc
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.list
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_DATA SEGMENT DWORD PUBLIC 'DATA'
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public _LdrpLockPrefixTable
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_LdrpLockPrefixTable label dword
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dd offset FLAT:Lock1
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dd offset FLAT:Lock2
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dd offset FLAT:Lock3
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dd offset FLAT:Lock4
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dd offset FLAT:Lock5
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dd offset FLAT:Lock6
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dd offset FLAT:Lock7
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dd 0
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_DATA ENDS
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_TEXT SEGMENT PARA PUBLIC 'CODE'
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ASSUME DS:FLAT, ES:FLAT, SS:NOTHING, FS:NOTHING, GS:NOTHING
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EXTRNP _RtlpWaitForCriticalSection,1
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EXTRNP _RtlpUnWaitCriticalSection,1
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if DEVL
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EXTRNP _RtlpNotOwnerCriticalSection,1
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endif
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if DBG
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EXTRNP _RtlpCriticalSectionIsOwned,1
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endif
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CriticalSection equ [esp + 4]
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page , 132
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subttl "RtlEnterCriticalSection"
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;++
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;
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; NTSTATUS
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; RtlEnterCriticalSection(
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; IN PRTL_CRITICAL_SECTION CriticalSection
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; )
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;
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; Routine Description:
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;
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; This function enters a critical section.
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;
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; Arguments:
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;
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; CriticalSection - supplies a pointer to a critical section.
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;
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; Return Value:
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;
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; STATUS_SUCCESS or raises an exception if an error occured.
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;
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;--
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align 16
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cPublicProc _RtlEnterCriticalSection,1
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cPublicFpo 1,0
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mov ecx,fs:PcTeb ; get current TEB address
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mov edx,CriticalSection ; get address of critical section
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cmp CsSpinCount[edx],0 ; check if spin count is zero
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jne short Ent40 ; if ne, spin count specified
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;
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; Attempt to acquire critical section.
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;
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Lock1: ;
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lock inc dword ptr CsLockCount[edx] ; increment lock count
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jnz short Ent20 ; if nz, already owned
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;
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; Set critical section owner and initialize recursion count.
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;
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Ent10:
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if DBG
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cmp CsOwningThread[edx],0
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je @F
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stdCall _RtlpCriticalSectionIsOwned, <edx>
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mov ecx,fs:PcTeb ; get current TEB address
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mov edx,CriticalSection ; get address of critical section
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@@:
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endif ; DBG
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mov eax,TbClientId + 4[ecx] ; get current client ID
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mov CsOwningThread[edx],eax ; set critical section owner
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mov dword ptr CsRecursionCount[edx],1 ; set recursion count
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if DBG
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inc dword ptr TbCountOfOwnedCriticalSections[ecx] ; increment owned count
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mov eax,CsDebugInfo[edx] ; get debug information address
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inc dword ptr CsEntryCount[eax] ; increment entry count
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endif ; DBG
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xor eax,eax ; set success status
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stdRET _RtlEnterCriticalSection
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;
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; The critical section is already owned, but may be owned by the current thread.
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;
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align 16
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Ent20: mov eax,TbClientId + 4[ecx] ; get current client ID
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cmp CsOwningThread[edx],eax ; check if current thread is owner
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jne short Ent30 ; if ne, current thread not owner
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inc dword ptr CsRecursionCount[edx] ; increment recursion count
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if DBG
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mov eax,CsDebugInfo[edx] ; get debug information address
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inc dword ptr CsEntryCount[eax] ; increment entry count
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endif ; DBG
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xor eax,eax ; set success status
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stdRET _RtlEnterCriticalSection
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;
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; The critcal section is owned by another thread and the current thread must
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; wait for ownership.
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;
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Ent30: stdCall _RtlpWaitForCriticalSection, <edx> ; wait for ownership
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mov ecx,fs:PcTeb ; get current TEB address
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mov edx,CriticalSection ; get address of critical section
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jmp Ent10 ; set owner and recursion count
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;
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; A nonzero spin count is specified.
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;
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align 16
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Ent40: mov eax,TbClientId + 4[ecx] ; get current client ID
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cmp CsOwningThread[edx],eax ; check if current thread is owner
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jne short Ent50 ; if ne, current thread not owner
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;
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; The critical section is owned by the current thread. Increment the lock
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; count and the recursion count.
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;
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Lock6: ;
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lock inc dword ptr CsLockCount[edx] ; increment lock count
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inc dword ptr CsRecursionCount[edx] ; increment recursion count
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if DBG
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mov eax,CsDebugInfo[edx] ; get debug information address
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inc dword ptr CsEntryCount[eax] ; increment entry count
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endif ; DBG
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xor eax,eax ; set success status
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stdRET _RtlEnterCriticalSection
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;
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; A nonzero spin count is specified and the current thread is not the owner.
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;
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align 16
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Ent50: push CsSpinCount[edx] ; get spin count value
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Ent60: mov eax,-1 ; set comparand value
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mov ecx,0 ; set exchange value
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Lock7:
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lock cmpxchg dword ptr CsLockCount[edx],ecx ; attempt to acquire critical section
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jnz short Ent70 ; if nz, critical section not acquired
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;
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; The critical section has been acquired. Set the owning thread and the initial
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; recursion count.
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;
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add esp,4 ; remove spin count from stack
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mov ecx,fs:PcTeb ; get current TEB address
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mov eax,TbClientId + 4[ecx] ; get current client ID
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mov CsOwningThread[edx],eax ; set critical section owner
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mov dword ptr CsRecursionCount[edx],1 ; set recursion count
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if DBG
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inc dword ptr TbCountOfOwnedCriticalSections[ecx] ; increment owned count
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mov eax,CsDebugInfo[edx] ; get debug information address
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inc dword ptr CsEntryCount[eax] ; increment entry count
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endif ; DBG
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xor eax,eax ; set success status
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stdRET _RtlEnterCriticalSection
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;
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; The critical section is currently owned. Spin until it is either unowned
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; or the spin count has reached zero.
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;
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; If waiters are present, don't spin on the lock since we will never see it go free
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;
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Ent70: cmp CsLockCount[edx],1 ; check if waiters are present,
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jge short Ent76 ; if ge 1, then do not spin
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Ent75: YIELD
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cmp CsLockCount[edx],-1 ; check if lock is owned
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je short Ent60 ; if e, lock is not owned
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dec dword ptr [esp] ; decrement spin count
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jnz short Ent75 ; if nz, continue spinning
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Ent76: add esp,4 ; remove spin count from stack
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mov ecx,fs:PcTeb ; get current TEB address
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jmp Lock1 ;
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stdENDP _RtlEnterCriticalSection
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page , 132
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subttl "RtlLeaveCriticalSection"
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;++
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;
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; NTSTATUS
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; RtlLeaveCriticalSection(
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; IN PRTL_CRITICAL_SECTION CriticalSection
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; )
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;
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; Routine Description:
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;
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; This function leaves a critical section.
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;
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; Arguments:
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;
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; CriticalSection - supplies a pointer to a critical section.
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;
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; Return Value:
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;
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; STATUS_SUCCESS or raises an exception if an error occured.
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;
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;--
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align 16
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cPublicProc _RtlLeaveCriticalSection,1
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cPublicFpo 1,0
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mov edx,CriticalSection
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if DBG
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mov ecx,fs:PcTeb ; (ecx) == NtCurrentTeb()
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mov eax,TbClientId+4[ecx] ; (eax) == NtCurrentTeb()->ClientId.UniqueThread
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cmp eax,CsOwningThread[edx]
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je @F
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stdCall _RtlpNotOwnerCriticalSection, <edx>
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mov eax,STATUS_INVALID_OWNER
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stdRET _RtlLeaveCriticalSection
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@@:
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endif ; DBG
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xor eax,eax ; Assume STATUS_SUCCESS
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dec dword ptr CsRecursionCount[edx]
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jnz leave_recurs ; skip if only leaving recursion
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mov CsOwningThread[edx],eax ; clear owning thread id
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if DBG
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mov ecx,fs:PcTeb ; (ecx) == NtCurrentTeb()
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dec dword ptr TbCountOfOwnedCriticalSections[ecx]
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endif ; DBG
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Lock2:
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lock dec dword ptr CsLockCount[edx] ; interlocked dec of
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; ... CriticalSection->LockCount
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jge @F
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stdRET _RtlLeaveCriticalSection
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@@:
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stdCall _RtlpUnWaitCriticalSection, <edx>
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xor eax,eax ; return STATUS_SUCCESS
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stdRET _RtlLeaveCriticalSection
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align 16
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leave_recurs:
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Lock3:
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lock dec dword ptr CsLockCount[edx] ; interlocked dec of
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; ... CriticalSection->LockCount
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stdRET _RtlLeaveCriticalSection
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_RtlLeaveCriticalSection endp
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page ,132
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subttl "RtlTryEnterCriticalSection"
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;++
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;
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; BOOL
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; RtlTryEnterCriticalSection(
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; IN PRTL_CRITICAL_SECTION CriticalSection
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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 enter a critical section without blocking.
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;
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; Arguments:
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;
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; CriticalSection (a0) - Supplies a pointer to a critical section.
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;
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; Return Value:
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;
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; If the critical section was successfully entered, then a value of TRUE
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; is returned as the function value. Otherwise, a value of FALSE is returned.
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;
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;--
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CriticalSection equ [esp + 4]
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cPublicProc _RtlTryEnterCriticalSection,1
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cPublicFpo 1,0
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mov ecx,CriticalSection ; interlocked inc of
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mov eax, -1 ; set value to compare against
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mov edx, 0 ; set value to set
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Lock4:
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lock cmpxchg dword ptr CsLockCount[ecx],edx ; Attempt to acquire critsect
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jnz short tec10 ; if nz, critsect already owned
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mov eax,fs:TbClientId+4 ; (eax) == NtCurrentTeb()->ClientId.UniqueThread
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mov CsOwningThread[ecx],eax
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mov dword ptr CsRecursionCount[ecx],1
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if DBG
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mov eax,fs:PcTeb ; (ecx) == NtCurrentTeb()
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inc dword ptr TbCountOfOwnedCriticalSections[eax]
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endif ; DBG
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mov eax, 1 ; set successful status
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stdRET _RtlTryEnterCriticalSection
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tec10:
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;
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; The critical section is already owned. If it is owned by another thread,
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; return FALSE immediately. If it is owned by this thread, we must increment
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; the lock count here.
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;
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mov eax, fs:TbClientId+4 ; (eax) == NtCurrentTeb()->ClientId.UniqueThread
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cmp CsOwningThread[ecx], eax
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jz tec20 ; if eq, this thread is already the owner
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xor eax, eax ; set failure status
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YIELD
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stdRET _RtlTryEnterCriticalSection
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tec20:
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;
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; This thread is already the owner of the critical section. Perform an atomic
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; increment of the LockCount and a normal increment of the RecursionCount and
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; return success.
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;
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Lock5:
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lock inc dword ptr CsLockCount[ecx]
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inc dword ptr CsRecursionCount[ecx]
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mov eax, 1
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stdRET _RtlTryEnterCriticalSection
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stdENDP _RtlTryEnterCriticalSection
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_TEXT ends
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end
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