A method and apparatus are provided for dispatch group checkpointing in a
microprocessor, including provisions for handling partially completed
dispatch groups and instructions which modify system coherent state prior
to completion. An instruction checkpoint retry mechanism is implemented
to recover from soft errors in logic. The processor is able to dispatch
fixed point unit (FXU), load/store unit (LSU), and floating point unit
(FPU) or vector multimedia extension (VMX) instructions on the same
cycle. Store data is written to a store queue when a store instruction
finishes executing. The data is held in the store queue until the store
instruction is checkpointed, at which point it can be released to the
coherently shared level 2 (L2) cache.