https://libre-soc.org/3d_gpu/architecture/6600scoreboard/600x-compunit_multi_rw.jpg https://libre-soc.org/3d_gpu/architecture/6600scoreboard/600x-dependence_cell_multi_pending.jpg the original 6600 scoreboard is single-signal request-ack protection for multiple reads on the regfile. overporting is then added so that multiple batches of ALUs can simultaneously read (and write) to the regfile. we cannot do massive-way regfile porting. additionally we need to do *different* regfiles for POWER: one of these is the "Branch Control" Regfile, including CR0, CTR and other conditional registers. therefore it becomes more important to have fine-grain control over the regfile, meaning that multiple go-read/req and go-write/req wires are needed per FunctionUnit.