Patent ID: 6282639
Filing Date: 2001-08-28
Classification: G06F

Abstract:
The branch prediction mechanism with improved branch accuracy, comprising:a RAM that stores the present state for each of a plurality of branch history state machines, said RAM having an output, said RAM being addressed by a combination of bits comprising a first part and a second part;said first part being bits from a branch address; andsaid second part being bits indicating the direction of previous branches;a branch prediction cache having a Hit/Miss information output, said Hit/Miss information output indicating a miss when there is no match on said branch address in said branch prediction cache; andprediction direction logic, said logic having inputs from said Hit/Miss output and said RAM, said predicted direction logic using said Hit/Miss output to inhibit predictions of taken branches based on the present state data read from said history RAM, whenever said Hit/Miss output indicates a miss.