Abstract: A data processor has a central processing unit and at least one pipelined memory controller circuitry. The central processing unit addresses data in the memory using a virtual address memory table lookaside buffer and features a data miss recovery circuitry wherein, after a memory access error condition has been detected, the instruction causing the error condition, and those instructions entering the memory pipeline after the instruction causing the error condition, are replayed. The method and apparatus for replaying the instructions use first in-first out buffers for storing the virtual address data and instruction status data relating to each memory access instruction. That stored data is then retrieved after an error condition is detected so that the instruction sequence, beginning at the data miss, can be replayed.

Abstract: In a parallel data processing system having a plurality of separately operating arithmetic processing units, a method and apparatus allows a plurality of branch instructions to be operated upon in a single machine cycle. The branch instructions have associated therewith a hierarchical priority system and the method and apparatus determine which branch, if any, should be taken. In particular, the method and apparatus simultaneously determine, during the parallel execution of the branch instructions, whether any branch test condition associated with a branch instruction is true, and independently, the target address for each branch instruction and a fall-through instruction address if a branch instruction is not taken.