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| author | Rémi Denis-Courmont <remi@remlab.net> | 2022-09-12 18:53:18 +0300 |
|---|---|---|
| committer | James Almer <jamrial@gmail.com> | 2022-09-13 16:50:43 -0300 |
| commit | ff14e3739393147b4596245ea511ec43a4ce6448 (patch) | |
| tree | e063dea56357c48cff0cdca2aff86dd9e4e0077f /doc | |
| parent | d808070547a867a8f3f7b97fdff3574576213c07 (diff) | |
| download | ffmpeg-ff14e3739393147b4596245ea511ec43a4ce6448.tar.gz | |
configure/riscv: detect fast CLZ
RISC-V defines the CLZ instruction as part of the ratified Zbb subset
of the (not yet ratified) bit mapulation extension (B). We can detect
it from the __riscv_zbb predefined constant. At least GCC 12 already
supports this correctly.
Note that the macro will be non-zero if supported, zero if enabled
in the compiler flags (e.g. -march=rv64gzbb) but not known to the
compiler, and undefined otherwise.
Diffstat (limited to 'doc')
0 files changed, 0 insertions, 0 deletions