OvmfPkg/XenBusDxe/Ia32/TestAndClearBit.nasm


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SECTION .text

; INT32
; EFIAPI
; TestAndClearBit (
;   IN  INT32 Bit,
;   IN  volatile VOID* Address
;   );
global ASM_PFX(TestAndClearBit)
ASM_PFX(TestAndClearBit):
  mov ecx, [esp + 4]
  mov edx, [esp + 8]
  lock btr [edx], ecx
  sbb eax, eax
  ret