The x86 architecture is the weirdo, part 2

Re:The x86 architecture is the weirdo, part 2 by Jasper_ on Friday April 22, 2022 @10:14AM (#31121794)

Fusion isn't cheap and I'd say it's part of the weirdness bucket to rely on fusion instead of making a combined instruction.

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Re:The x86 architecture is the weirdo, part 2 by brucehoult on Friday April 22, 2022 @07:07PM (#31129352)

Modern x86 and ARM both rely on fusing a compare instruction with a following conditional branch -- something RISC-V doesn't have to do as conditional branches already incorporate the compare and there are no condition codes.

So if fusion is a weirdness it's a nearly universal one.

The good thing about fusion is the program works fine if you don't do it, so low end minimal area CPUs such as microcontrollers can just not bother.

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