@oe1cxw Sir I have a silly question. How does one implement bitmasks in rv32i/rv64i, given the bit instructions are in an extension? Surely you need bitmasks in order to implement eg 16-bit ints
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Bit wise and or and xor are part of the base arch.
This. And re 16-bit ints specifically, usually they are handled by XLEN-16 bit left shift followed by right shift. The right shift is an arithmetic shift for signed and logical for unsigned. Bitmanip doesn't add anything here, just recommends to macro-op fuse pairs of shifts.
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Ok. So even without the bitmanip extension we have and, or, xor and four shifts? This is starting to sound a lot less spartan than I assumed it was
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Yes. Three shifts in base: sll, srl, and sra Bitmanip adds more shifts: rol, ror, slo, sro, fsl, fsr
End of conversation
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