← Back to context Comment by wmf 13 hours ago There are a bunch of undocumented flags and instructions beyond TSO. 4 comments wmf Reply astrange 10 hours ago Trust me on this one? chadaustin 6 hours ago https://dougallj.wordpress.com/2022/11/09/why-is-rosetta-2-f...> Apple M1 has an undocumented extension that, when enabled, ensures instructions like ADDS, SUBS and CMP compute PF and AF and store them as bits 26 and 27 of NZCV respectively, providing accurate emulation with no performance penalty. astrange 5 hours ago Oh yeah, maybe that one was too obscure for me. I don't think I've ever seen something use PF/AF…You do want FEAT_AFP though, so you do want ARMv8.6+. 1 reply →
astrange 10 hours ago Trust me on this one? chadaustin 6 hours ago https://dougallj.wordpress.com/2022/11/09/why-is-rosetta-2-f...> Apple M1 has an undocumented extension that, when enabled, ensures instructions like ADDS, SUBS and CMP compute PF and AF and store them as bits 26 and 27 of NZCV respectively, providing accurate emulation with no performance penalty. astrange 5 hours ago Oh yeah, maybe that one was too obscure for me. I don't think I've ever seen something use PF/AF…You do want FEAT_AFP though, so you do want ARMv8.6+. 1 reply →
chadaustin 6 hours ago https://dougallj.wordpress.com/2022/11/09/why-is-rosetta-2-f...> Apple M1 has an undocumented extension that, when enabled, ensures instructions like ADDS, SUBS and CMP compute PF and AF and store them as bits 26 and 27 of NZCV respectively, providing accurate emulation with no performance penalty. astrange 5 hours ago Oh yeah, maybe that one was too obscure for me. I don't think I've ever seen something use PF/AF…You do want FEAT_AFP though, so you do want ARMv8.6+. 1 reply →
astrange 5 hours ago Oh yeah, maybe that one was too obscure for me. I don't think I've ever seen something use PF/AF…You do want FEAT_AFP though, so you do want ARMv8.6+. 1 reply →
Trust me on this one?
https://dougallj.wordpress.com/2022/11/09/why-is-rosetta-2-f...
> Apple M1 has an undocumented extension that, when enabled, ensures instructions like ADDS, SUBS and CMP compute PF and AF and store them as bits 26 and 27 of NZCV respectively, providing accurate emulation with no performance penalty.
Oh yeah, maybe that one was too obscure for me. I don't think I've ever seen something use PF/AF…
You do want FEAT_AFP though, so you do want ARMv8.6+.
1 reply →