3 ms·
1-to-1 isn’t entirely true right now. sonicBOOM includes a feature called short forwards optimization which can turn certain branches into flag setting ops (and
by skavi 3y ago
1-to-1 isn’t entirely true right now. sonicBOOM includes a feature called short forwards optimization which can turn certain branches into flag setting ops (and make the former branch shadow predicated). So one instruction always produces one uop, but not necessarily always the same one.
- brucehoult 3y agoSiFive's U74 (found in the VisionFive 2, Star64, PineTab-V, Milk-V Mars) does this. The conditional branch travels down pipe A, the following instruction down pipe B. If the conditional branch turns out to be taken then the instruction in pipe B is NOP'd rather than taking a branch mispredict.