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Diffstat (limited to 'private/ntos/ex/i386/fmutex.asm')
| -rw-r--r-- | private/ntos/ex/i386/fmutex.asm | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/private/ntos/ex/i386/fmutex.asm b/private/ntos/ex/i386/fmutex.asm new file mode 100644 index 000000000..6f419d35a --- /dev/null +++ b/private/ntos/ex/i386/fmutex.asm @@ -0,0 +1,186 @@ + TITLE "Fast Mutex Support" +;++ +; +; Copyright (c) 1994 Microsoft Corporation +; +; Module Name: +; +; spinlock.asm +; +; Abstract: +; +; This module implements teh code necessary to acquire and release fast +; mutexs without raising or lowering IRQL. +; +; Author: +; +; David N. Cutler (davec) 26-May-1994 +; +; Environment: +; +; Kernel mode only. +; +; Revision History: +; +;-- + +.386p + .xlist +include ks386.inc +include callconv.inc ; calling convention macros +include mac386.inc + .list + + EXTRNP _KeSetEventBoostPriority, 2 + EXTRNP _KeWaitForSingleObject, 5 + +ifdef NT_UP + LOCK_ADD equ add + LOCK_DEC equ dec +else + LOCK_ADD equ lock add + LOCK_DEC equ lock dec +endif + +_TEXT$00 SEGMENT DWORD PUBLIC 'CODE' + ASSUME DS:FLAT, ES:FLAT, SS:NOTHING, FS:NOTHING, GS:NOTHING + +;++ +; +; VOID +; FASTCALL +; ExAcquireFastMutexUnsafe ( +; IN PFAST_MUTEX FastMutex +; ) +; +; Routine description: +; +; This function acquires ownership of a fast mutex, but does not raise +; IRQL to APC level. +; +; Arguments: +; +; (ecx) = FastMutex - Supplies a pointer to a fast mutex. +; +; Return Value: +; +; None. +; +;-- + +cPublicFastCall ExAcquireFastMutexUnsafe,1 +cPublicFpo 0,0 + + LOCK_DEC dword ptr [ecx].FmCount ; decrement lock count + jnz short afm10 ; if nz, ownership not obtained + fstRet ExAcquireFastMutexUnsafe ; return + +afm10: inc dword ptr [ecx].FmContention ; increment contention count + add ecx, FmEvent ; wait for ownership event + stdCall _KeWaitForSingleObject,<ecx,WrExecutive,0,0,0> ; + fstRet ExAcquireFastMutexUnsafe ; return + +fstENDP ExAcquireFastMutexUnsafe + +;++ +; +; VOID +; FASTCALL +; ExReleaseFastMutexUnsafe ( +; IN PFAST_MUTEX FastMutex +; ) +; +; Routine description: +; +; This function releases ownership of a fast mutex, and does nt +; restore IRQL to its previous value. +; +; Arguments: +; +; (ecx) = FastMutex - Supplies a pointer to a fast mutex. +; +; Return Value: +; +; None. +; +;-- + +cPublicFastCall ExReleaseFastMutexUnsafe,1 +cPublicFpo 0,0 + + LOCK_ADD dword ptr [ecx].FmCount, 1 ; increment ownership count + jng short rfm10 ; if ng, waiter present + fstRet ExReleaseFastMutexUnsafe ; return + +rfm10: add ecx, FmEvent ; compute event address + stdCall _KeSetEventBoostPriority,<ecx, 0> ; set ownerhsip event + fstRet ExReleaseFastMutexUnsafe ; return + +fstENDP ExReleaseFastMutexUnsafe + + +;++ +; +; BOOLEAN +; FASTCALL +; ExTryToAcquireFastMutexUnsafe ( +; IN PFAST_MUTEX FastMutex +; ) +; +; Routine description: +; +; This function attempts to acquire ownership of a fast mutex, and if +; successful, does not raise IRQL to APC level. +; +; Arguments: +; +; (ecx) = FastMutex - Supplies a pointer to a fast mutex. +; +; Return Value: +; +; Returns TRUE if the FAST_MUTEX was acquired; otherwise false +; +;-- + +if 0 + +cPublicFastCall ExTryToAcquireFastMutexUnsafe,1 +cPublicFpo 0,0 + +ifdef NT_UP + + cli ; disable interrupts + +endif + + cmp dword ptr [ecx].FmCount, 1 ; check if mutex already owned + jne short tam10 ; if ne, mutex already owned + +ifndef NT_UP + + mov eax, 1 ; set value to compare against + mov edx, 0 ; set value to set + lock cmpxchg dword ptr [ecx].FmCount, edx ; attempt to acquire fast mutex + jne short tam10 ; if ne, mutex already owned + +else + + mov dword ptr [ecx].FmCount, 0 ; set mutex owned + sti ; enable interrupts + +endif + + mov eax, 1 ; set return value + fstRet ExTryToAcquireFastMutexUnsafe ; return + +tam10: xor eax, eax ; set return value + fstRet ExTryToAcquireFastMutexUnsafe ; return + +fstENDP ExTryToAcquireFastMutexUnsafe + +endif + + +_TEXT$00 ends + + end |