@regehr @resistor @barrelshifter For some examples:
- PPC and ARM A64 very visibly go for the rotate+mask approach. PPC does everything with rot left + mask (see e.g. https://devblogs.microsoft.com/oldnewthing/20180810-00/?p=99465), A64 is rot right + mask (https://www.scs.stanford.edu/~zyedidia/arm64/ubfm.html), and the A64 logic immediates use basically the same mask generation logic. (So it can be shared if desired, in a small design.)
- I have seen datapath details for some Intel designs that used funnel shift right for all usual shifts.
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Fabian Giesen (rygorous@mastodon.gamedev.place)'s status on Thursday, 29-May-2025 03:16:57 JST Fabian Giesen