Patent ID: 6490509
Filing Date: 2002-12-03
Classification: G06F

Abstract:
A car controlling unit, comprising:interrupt request issuing means for issuing an interrupt request being associated with one of a plurality of interrupt levels, which indicates a priority of an interrupt processing; an interrupt controller which receives said interrupt request and decides whether or not said interrupt request is allowed, based on the interrupt level associated with said interrupt request thus received; a central processing unit which executes a task processing and an interrupt processing, and which suspends the task processing or the interrupt processing being executed when said interrupt request has been allowed, so as to execute said interrupt processing whose interrupt request has been allowed; and a memory having a plurality of task areas to be used as a stack by said task processing and a plurality of interrupt areas to be used as a stack by interrupt processing, wherein, a number of said interrupt areas is equal to a number of said interrupt levels; said central processing unit utilizes any one of said task areas as a stack in executing each of said task processing; and said central processing unit utilizes any one of said interrupt areas as a stack in executing said interrupt processing whose interrupt request has been allowed.