3 ms·
128-bit or 256-bit memsets via SIMD instructions are sufficient to saturate RAM bandwidth, so there wouldn't be much of a gain from having a dedicated instructi
by pcwalton 2y ago
128-bit or 256-bit memsets via SIMD instructions are sufficient to saturate RAM bandwidth, so there wouldn't be much of a gain from having a dedicated instruction.
(By the way, x86 does have a dedicated instruction--rep stosb--but compilers differ as to how often they use it, for the reason cited above.)
- anonymoushn 2y agoSupposedly rep movsb is faster than SIMD stores on very recent chips, for cases where you aren't actually hitting RAM with all your writes.
- tubs 2y agoThe gain is in power efficiency. Arm64 provides `dc zva` for this.