A universal buffered interface (UBIF 34) couples a local bus (32) to a global bus (24) and supports, on the local bus, up to four nodes. The nodes may be comprised of processors (22a, 28a), memory banks, and/or I/O interfaces. Each processor has an associated private memory. The UBIF includes bidirectional, first-in-first-out (FIFO) buffers, or queues, for each node and operates in conjunction with a two-level bus hierarchy. The UBIF supports decoupled global memory (26) read requests and replies, supports decoupled, atomic read-modify-write operations to Global Memory, and block-read support for transferring contiguous blocks of global memory to processors or I/O interfaces. The UBIF also enables the use of an inter-processor communication (IPC) mechanism that enables any processor to send an interrupt to any other processor or processors in the system during a single global bus cycle. An interrupt mask is transferred over the address bus during a specially marked bus cycle, the interrupt mask identifying the processor or processors to be interrupted.