| 摘要 |
A branch processing unit (BPU) is used, in an exemplary embodiment, in a superscalar, superpipelined microprocessor compatible with the x86 instruction set architecture. The BPU includes a target cache organized in banks to support split prefetching. Prefetch requests (addressing a prefetch block of 16 bytes) are separated into low and high block addresses (addressing split blocks of 8 bytes). The low and high block addresses differ in bit position [3] designated a bank select bit, where the low block address of an associated prefetch request may be designated by a [1 or 0] such that a split block associated with a low block address may be allocated into either bank of the target cache (i.e., the low block of a prefetch request can start on an 8 byte alignment rather than the 16 byte alignment). For each prefetch request that includes both low and high block addresses, respective banks of the target cache are successively accessed based on the state of the bank select bit, such that the low block address is used to access one bank and the high block address is used to access the other bank. |
