Hardware semaphore intended for a multi-processor system

Abstract

The invention relates to a method in a hardware semaphore lock (L1-LN) intended for a multi-processor system, which semaphore lock (L1-LN) protects a shared resource (R1-RN) in connection with said system in such a way that only a process which has reserved the semaphore lock (L1-LN) and has thus become a holder of said lock, has access to use the resource protected by said lock. According to the invention, the semaphore lock (L1-LN) is reserved by a single read operation of a memory location representing the semaphore lock by the process software. The read operation returns to the process the number of vacant holder positions, i.e. keyholes vacant at the time of the reservation of said lock. The most significant advantage of the invention is that the implementation of the semaphore lock does not require the support of the system for atomic read/write operations. In an advantageous embodiment of the invention, the semaphore lock (L1-LN) uses an interrupt signal (INT) to inform the system about the release of a resource (R1-RN) protected by it. The invention also relates to a hardware-based semaphore lock (L1-LN) implementing the method, as well as a semaphore module (SB) comprising several semaphore locks.

Dependencies are inferred from the claim text.