4 ms·
If I understand correctly from what they've said so far, there is no RAM/register file with N*3 ports, it just reuses the outputs of the functional units. That
by Rusky 12y ago
If I understand correctly from what they've said so far, there is no RAM/register file with N*3 ports, it just reuses the outputs of the functional units.
That's also nowhere near the source of slowness in the Itanium.
- thesz 12y agoOkay. The reuse of output from functional units was done in TTA CPUs (Transport Triggered Architectures). Guess how they fare if you probable never heard of them? Guess also how fast or slow they are compared to regular OOO CPUs. You will be right if you guess that they are not that good in terms of raw performance and they are not that fast in terms of operating frequency. They are not fast in either way precisely because they use crossbar as a operand delivery network. They also can have FIFOs as the switching network or as an another functional unit dedicated to spreading information, but most often it is not used.