OvmfPkg/XenBusDxe/X64/TestAndClearBit.asm

   1 .code
   2
   3 ; INT32
   4 ; EFIAPI
   5 ; TestAndClearBit (
   6 ;   IN  INT32 Bit,                // rcx
   7 ;   IN  volatile VOID* Address    // rdx
   8 ;   );
   9 TestAndClearBit PROC
  10   lock
  11   btr [rdx], ecx
  12   sbb eax, eax
  13   ret
  14 TestAndClearBit ENDP
  15
  16 END