Apparatus and method for transaction tag mapping between bus domains

摘要

An apparatus and method to provide tag mapping between bus domains across a bus bridge. The preferred embodiments provide a simple tag mapping design while maintaining unique IDs for all outstanding transactions for an overall increase in computer system performance. The preferred embodiment is a bus bridge between a GPUL bus for a GPUL PowerPC microprocessor from International Business Machines Corporation (IBM) and an output high speed interface (MPI bus). In preferred embodiments, the transaction mapping logic ensures that transactions generated by any logical unit (CPU) appear to originate from a single logical unit.