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by mmaunder 1926 days ago
A common misconception about RISC processors.
1 comments
chrisseaton 1926 days ago
It’s not a RISC thing - CISC implementations do exactly the same kind of fusion for similar pairs of operations.
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userbinator 1926 days ago
It has a bit less gain on a RISC due to the code density (or lack thereof), since it requires more fetch bandwidth. Apple works around this by using a very wide front-end: https://news.ycombinator.com/item?id=25257932
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_chris_ 1926 days ago
x86-64 code density is more than 4 bytes / instruction.
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saagarjha 1926 days ago
That looks like inverse density.
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chrisseaton 1926 days ago
Isn’t that the point?
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