CriticalSection的ASM原代码

title " Critical Section Support "

; ++

;

; Module Name:

;

; critsect.asm

;

; Abstract:

;

; This module implements functions to support user mode critical sections.

;

; Author:

;

; Bryan M. Willman (bryanwi) 2 - Oct - 91

;

; Environment:

;

; Any mode.

;

; Revision History:

;

; --

.486p

.xlist

include ks386.inc

include callconv.inc ; calling convention macros

include mac386.inc

.list

_DATA SEGMENT DWORD PUBLIC ' DATA '

public _LdrpLockPrefixTable

_LdrpLockPrefixTable label dword

dd offset FLAT:Lock1

dd offset FLAT:Lock2

dd offset FLAT:Lock3

dd offset FLAT:Lock4

dd offset FLAT:Lock5

dd offset FLAT:Lock6

dd offset FLAT:Lock7

dd 0

_DATA ENDS

_TEXT SEGMENT PARA PUBLIC ' CODE '

ASSUME DS:FLAT, ES:FLAT, SS:NOTHING, FS:NOTHING, GS:NOTHING

EXTRNP _RtlpWaitForCriticalSection, 1

EXTRNP _RtlpUnWaitCriticalSection, 1

if DEVL

EXTRNP _RtlpNotOwnerCriticalSection, 1

endif

if DBG

EXTRNP _RtlpCriticalSectionIsOwned, 1

endif

CriticalSection equ [esp + 4 ]

page , 132

subttl " RtlEnterCriticalSection "

; ++

;

; NTSTATUS

; RtlEnterCriticalSection(

; IN PRTL_CRITICAL_SECTION CriticalSection

; )

;

; Routine Description:

;

; This function enters a critical section.

;

; Arguments:

;

; CriticalSection - supplies a pointer to a critical section.

;

; Return Value:

;

; STATUS_SUCCESS or raises an exception if an error occured.

;

; --

align 16

cPublicProc _RtlEnterCriticalSection, 1

cPublicFpo 1 , 0

mov ecx,fs:PcTeb ; get current TEB address

mov edx,CriticalSection ; get address of critical section

cmp CsSpinCount[edx], 0 ; check if spin count is zero

jne short Ent40 ; if ne, spin count specified

;

; Attempt to acquire critical section.

;

Lock1: ;

lock inc dword ptr CsLockCount[edx] ; increment lock count

jnz short Ent20 ; if nz, already owned

;

; Set critical section owner and initialize recursion count.

;

Ent10:

if DBG

cmp CsOwningThread[edx], 0

je @F

stdCall _RtlpCriticalSectionIsOwned, < edx >

mov ecx,fs:PcTeb ; get current TEB address

mov edx,CriticalSection ; get address of critical section

@@:

endif ; DBG

mov eax,TbClientId + 4 [ecx] ; get current client ID

mov CsOwningThread[edx],eax ; set critical section owner

mov dword ptr CsRecursionCount[edx], 1 ; set recursion count

if DBG

inc dword ptr TbCountOfOwnedCriticalSections[ecx] ; increment owned count

mov eax,CsDebugInfo[edx] ; get debug information address

inc dword ptr CsEntryCount[eax] ; increment entry count

endif ; DBG

xor eax,eax ; set success status

stdRET _RtlEnterCriticalSection

;

; The critical section is already owned, but may be owned by the current thread.

;

align 16

Ent20: mov eax,TbClientId + 4 [ecx] ; get current client ID

cmp CsOwningThread[edx],eax ; check if current thread is owner

jne short Ent30 ; if ne, current thread not owner

inc dword ptr CsRecursionCount[edx] ; increment recursion count

if DBG

mov eax,CsDebugInfo[edx] ; get debug information address

inc dword ptr CsEntryCount[eax] ; increment entry count

endif ; DBG

xor eax,eax ; set success status

stdRET _RtlEnterCriticalSection

;

; The critcal section is owned by another thread and the current thread must

; wait for ownership.

;

Ent30: stdCall _RtlpWaitForCriticalSection, < edx > ; wait for ownership

mov ecx,fs:PcTeb ; get current TEB address

mov edx,CriticalSection ; get address of critical section

jmp Ent10 ; set owner and recursion count

;

; A nonzero spin count is specified.

;

align 16

Ent40: mov eax,TbClientId + 4 [ecx] ; get current client ID

cmp CsOwningThread[edx],eax ; check if current thread is owner

jne short Ent50 ; if ne, current thread not owner

;

; The critical section is owned by the current thread. Increment the lock

; count and the recursion count.

;

Lock6: ;

lock inc dword ptr CsLockCount[edx] ; increment lock count

inc dword ptr CsRecursionCount[edx] ; increment recursion count

if DBG

mov eax,CsDebugInfo[edx] ; get debug information address

inc dword ptr CsEntryCount[eax] ; increment entry count

endif ; DBG

xor eax,eax ; set success status

stdRET _RtlEnterCriticalSection

;

; A nonzero spin count is specified and the current thread is not the owner.

;

align 16

Ent50: push CsSpinCount[edx] ; get spin count value

Ent60: mov eax, - 1 ; set comparand value

mov ecx, 0 ; set exchange value

Lock7:

lock cmpxchg dword ptr CsLockCount[edx],ecx ; attempt to acquire critical section

jnz short Ent70 ; if nz, critical section not acquired

;

; The critical section has been acquired. Set the owning thread and the initial

; recursion count.

;

add esp, 4 ; remove spin count from stack

mov ecx,fs:PcTeb ; get current TEB address

mov eax,TbClientId + 4 [ecx] ; get current client ID

mov CsOwningThread[edx],eax ; set critical section owner

mov dword ptr CsRecursionCount[edx], 1 ; set recursion count

if DBG

inc dword ptr TbCountOfOwnedCriticalSections[ecx] ; increment owned count

mov eax,CsDebugInfo[edx] ; get debug information address

inc dword ptr CsEntryCount[eax] ; increment entry count

endif ; DBG

xor eax,eax ; set success status

stdRET _RtlEnterCriticalSection

;

; The critical section is currently owned. Spin until it is either unowned

; or the spin count has reached zero.

;

; If waiters are present, don ' t spin on the lock since we will never see it go free

;

Ent70: cmp CsLockCount[edx], 1 ; check if waiters are present,

jge short Ent76 ; if ge 1 , then do not spin

Ent75: YIELD

cmp CsLockCount[edx], - 1 ; check if lock is owned

je short Ent60 ; if e, lock is not owned

dec dword ptr [esp] ; decrement spin count

jnz short Ent75 ; if nz, continue spinning

Ent76: add esp, 4 ; remove spin count from stack

mov ecx,fs:PcTeb ; get current TEB address

jmp Lock1 ;

stdENDP _RtlEnterCriticalSection

page , 132

subttl " RtlLeaveCriticalSection "

; ++

;

; NTSTATUS

; RtlLeaveCriticalSection(

; IN PRTL_CRITICAL_SECTION CriticalSection

; )

;

; Routine Description:

;

; This function leaves a critical section.

;

; Arguments:

;

; CriticalSection - supplies a pointer to a critical section.

;

; Return Value:

;

; STATUS_SUCCESS or raises an exception if an error occured.

;

; --

align 16

cPublicProc _RtlLeaveCriticalSection, 1

cPublicFpo 1 , 0

mov edx,CriticalSection

if DBG

mov ecx,fs:PcTeb ; (ecx) == NtCurrentTeb()

mov eax,TbClientId + 4 [ecx] ; (eax) == NtCurrentTeb() -> ClientId.UniqueThread

cmp eax,CsOwningThread[edx]

je @F

stdCall _RtlpNotOwnerCriticalSection, < edx >

mov eax,STATUS_INVALID_OWNER

stdRET _RtlLeaveCriticalSection

@@:

endif ; DBG

xor eax,eax ; Assume STATUS_SUCCESS

dec dword ptr CsRecursionCount[edx]

jnz leave_recurs ; skip if only leaving recursion

mov CsOwningThread[edx],eax ; clear owning thread id

if DBG

mov ecx,fs:PcTeb ; (ecx) == NtCurrentTeb()

dec dword ptr TbCountOfOwnedCriticalSections[ecx]

endif ; DBG

Lock2:

lock dec dword ptr CsLockCount[edx] ; interlocked dec of

;

CriticalSection -> LockCount

jge @F

stdRET _RtlLeaveCriticalSection

@@:

stdCall _RtlpUnWaitCriticalSection, < edx >

xor eax,eax ; return STATUS_SUCCESS

stdRET _RtlLeaveCriticalSection

align 16

leave_recurs:

Lock3:

lock dec dword ptr CsLockCount[edx] ; interlocked dec of

;

CriticalSection -> LockCount

stdRET _RtlLeaveCriticalSection

_RtlLeaveCriticalSection endp

page , 132

subttl " RtlTryEnterCriticalSection "

; ++

;

; BOOL

; RtlTryEnterCriticalSection(

; IN PRTL_CRITICAL_SECTION CriticalSection

; )

;

; Routine Description:

;

; This function attempts to enter a critical section without blocking.

;

; Arguments:

;

; CriticalSection (a0) - Supplies a pointer to a critical section.

;

; Return Value:

;

; If the critical section was successfully entered, then a value of TRUE

; is returned as the function value. Otherwise, a value of FALSE is returned.

;

; --

CriticalSection equ [esp + 4 ]

cPublicProc _RtlTryEnterCriticalSection, 1

cPublicFpo 1 , 0

mov ecx,CriticalSection ; interlocked inc of

mov eax, - 1 ; set value to compare against

mov edx, 0 ; set value to set

Lock4:

lock cmpxchg dword ptr CsLockCount[ecx],edx ; Attempt to acquire critsect

jnz short tec10 ; if nz, critsect already owned

mov eax,fs:TbClientId + 4 ; (eax) == NtCurrentTeb() -> ClientId.UniqueThread

mov CsOwningThread[ecx],eax

mov dword ptr CsRecursionCount[ecx], 1

if DBG

mov eax,fs:PcTeb ; (ecx) == NtCurrentTeb()

inc dword ptr TbCountOfOwnedCriticalSections[eax]

endif ; DBG

mov eax, 1 ; set successful status

stdRET _RtlTryEnterCriticalSection

tec10:

;

; The critical section is already owned. If it is owned by another thread,

; return FALSE immediately. If it is owned by this thread, we must increment

; the lock count here.

;

mov eax, fs:TbClientId + 4 ; (eax) == NtCurrentTeb() -> ClientId.UniqueThread

cmp CsOwningThread[ecx], eax

jz tec20 ; if eq, this thread is already the owner

xor eax, eax ; set failure status

YIELD

stdRET _RtlTryEnterCriticalSection

tec20:

;

; This thread is already the owner of the critical section. Perform an atomic

; increment of the LockCount and a normal increment of the RecursionCount and

; return success.

;

Lock5:

lock inc dword ptr CsLockCount[ecx]

inc dword ptr CsRecursionCount[ecx]

mov eax, 1

stdRET _RtlTryEnterCriticalSection

stdENDP _RtlTryEnterCriticalSection

_TEXT ends

end

CriticalSection的ASM原代码

CriticalSection的ASM原代码

你可能感兴趣的:(CriticalSection的ASM原代码)