On 7/31/23 17:27, Sean Anderson wrote:
Since ARMv5, the clz instruction allows for efficient implementation of
ffs/fls with builtins. Until ARMv7 (with Thumb-2), this instruction is
only available in ARM mode. LTO makes it difficult to force specific
functions to be in ARM mode, as it is effectively a form of very
aggressive inlining. To work around this, fls/ffs are implemented in
assembly for ARMv5 and ARMv6 when compiling U-Boot in Thumb mode.
Overall, this saves around 75 bytes per call.
Signed-off-by: Sean Anderson <sean.ander...@seco.com>
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I only tested this on ARMv8. If someone has an ARMv5 or ARMv6 board,
please test this.
+CC Linus since he may care about integrator.
--Sean
