INT 15 - TopView - "ENDC" - END CRITICAL REGION
AX = 101Ch
Return: task-switching enabled
Note:   this API call may be made from within a hardware interrupt handler
SeeAlso: AX=DE13h,AX=DE1Bh,INT 2F/AX=1682h,INT 60/DI=0603h

See also: 15101B

15101C - TopView - "ENDC" - END CRITICAL REGION