3 ms·
The "xor rax, rax" that I just saw at a quick glance makes me flinch. Still putting it on my reading list though. Sounds like a really interesting little toy pr
by xurukefi 3y ago
The "xor rax, rax" that I just saw at a quick glance makes me flinch. Still putting it on my reading list though. Sounds like a really interesting little toy project.
- seritools 3y agoTo explain the flinching (since I didn't catch it immediately): > In 64-bit mode, still use `xor r32, r32`, because writing a 32-bit reg zeros the upper 32. `xor r64, r64` is a waste of a byte, because it needs a REX prefix. (from https://stackoverflow.com/a/33668295/554577 https://stackoverflow.com/a/33668295/554577 )