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Re: [Minios-devel] [UNIKRAFT RFC PATCH 1/1] plat/common: Implement ffs/fls for non-x86 architectures

On 10/25/18 11:05 AM, Jianyong Wu wrote:
From: Jianyong Wu <Jianyong.Wu@xxxxxxx>

Some architectures like Arm64 don't have special instructions
like x86 to implement ffs/fls functions.

That's not true. Those functions can be implemented using the instruction clz (count leading zero) on Arm.

See the ARM ARM and [1] for more details on how to use them.


[1] https://en.wikipedia.org/wiki/Find_first_set

Julien Grall

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