3.6.8.10.3 FPU Instruction Kill

As is the case for all instructions executed within conditional branch speculative slots, floating-point instructions will be killed if a branch mispredict occurs. The CPU will recognize a mispredict prior to the end of the conditional branch R-stage (i.e., when the prior instruction status is available to forward). If the instruction in the first speculative slot is an FPU instruction, it will be issued to the FPU, but the CPU will assert a signal to kill the instruction for one cycle, forcing the FPU to subsequently abandon execution prior to it being committed. If the instruction in the second speculative slot is an FPU instruction, it will be abandoned prior to being issued to the FPU.

Legend: F = Fetch, A = Address decode, R = Read, X = Execute, W = Write back