riscv: Optimize hweight API with Zbb extension

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The Hamming Weight of a number is the total number of bits set in it, so
the cpop/cpopw instruction from Zbb extension can be used to accelerate
hweight() API.

Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20231112095244.4015351-1-xiao.w.wang@intel.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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Xiao Wang 2023-11-12 17:52:44 +08:00 • committed by Palmer Dabbelt

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commit 55ca8d7aa2

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78

arch/riscv/include/asm/arch_hweight.h

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4

arch/riscv/include/asm/bitops.h

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