decode 0
decode 1
readerPhase execute/opPhase issue
opPhase execute
callPhase/first called instruction
… repeated
writerPhase (which is also opPhase of the next instruction and readerPhase of the one after that)
Let’s see if I understand it right. The first part could well be in the encoder talk topic:
Decode 0 don’t produces anything? Are the readerPhase ops already ready, but waiting for the opPhase ones to be decoded so they can issue while reader phase executes? Or do the reader side ops on the flow side take one extra cycle to decode compared to the simple encoding in the exu side, and that is why there is this delay?
The decode 1 decodes the opPhase operations (and maybe the pick and writer phase too, finishing the effective decode?) so that the next cycle can be a issue phase (Mill does had an issue stage after all, only masked by phasing) while the reader operations that were already ready execute.
Is there a decode 2 stage?
Parallel to the opPhase execute, is the readerPhase of the called function/loop executing, assuming that the branch/exit predictor did it’s job? Or there is a bubble there? That is the only place where I see the readerPhase increasing the work done in a cycle when assuming a infinitely powerful decoder.
So, is the “callPhase/first called instruction” already at the opPhase of the called instruction?
And in the cycle the function returns (already at transfer phase, that occurs at the same time as the writer phase?), is the calling site already at opPhase? Or there is a bubble? Again, assuming perfect exit prediction.
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This reply was modified 9 years, 5 months ago by
Renesac.