Skip to content
Commit bce898f5 authored by Sean Anderson's avatar Sean Anderson Committed by Tom Rini
Browse files

arm: Use builtins for ffs/fls



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: default avatarSean Anderson <sean.anderson@seco.com>
parent a5899cc6
Loading
Loading
Loading
Loading
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Please register or to comment