add iterative multiplication unit

kuznia-rdzeni / coreblocks

RISC-V out-of-order core for education and research purposes

https://kuznia-rdzeni.github.io/coreblocks/

BSD 3-Clause "New" or "Revised" License

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add iterative multiplication unit #692

Closed Korbeusz closed 14 hours ago

Korbeusz commented 2 months ago

Passes standard multiplication tests

Korbeusz commented 1 month ago

There was a mistake in efficiency test. Those are real stats (number of idle cycles during 100 request of 32 bit numbers) . I was unaware that : res = yield from self.m.accept.call_try() waits one cycle itself.

dsp_width:18,dsp_number:4 -> 103
dsp_width:18,dsp_number:2 -> 203
dsp_width:8,dsp_number:4 -> 404
dsp_width:4,dsp_number:4 -> 1605 In order to improve efficiency we have to make ready signal belong to m.d.comb.

Korbeusz commented 1 month ago

After efficiency improvement we get:

dsp_width:18,dsp_number:4 -> 4
dsp_width:18,dsp_number:2 -> 104
dsp_width:8,dsp_number:4 -> 305
dsp_width:4,dsp_number:4 -> 1506 I think there is no room for improvement.

Korbeusz commented 1 month ago

Now we have:

dsp_width:18,dsp_number:4 -> 3
dsp_width:18,dsp_number:2 -> 103
dsp_width:8,dsp_number:4 -> 304
dsp_width:4,dsp_number:4 -> 1505