On Thu, Mar 9, 2017 at 7:49 PM, Steven Rostedt <rost...@goodmis.org> wrote: > > > On March 9, 2017 9:42:57 PM EST, Andy Lutomirski <l...@amacapital.net> wrote: >>On Thu, Mar 9, 2017 at 2:42 PM, Steven Rostedt <rost...@goodmis.org> >>wrote: >>> From: "Steven Rostedt (Red Hat)" <rost...@goodmis.org> >>> >>> Linus mentioned that doing two compares can be replaced by a single >>> compare. That is, instead of: >>> >>> movq $repeat_nmi, %rdx >>> cmpq 8(%rsp), %rdx >>> ja not_in_region >>> movq $end_repeat_nmi, %rdx >>> cmpq 8(%rsp), %rdx >>> ja in_region >>> >>> we can replace that with: >>> >>> movq 8(%rsp), %rdx >>> subq $repeat_nmi, %rdx >>> cmpq $end_repeat_nmi-repeat_nmi, %rdx >>> jb in_region >> >>Seems reasonable to me. Good luck ever noticing the speedup :) >> > > It had nothing to do with speedup. Linus said that the current code makes the > assembly programmer in him die a little. I want to cure that. >
One might argue that the world would be a better place if the assembly programmer in some people died a little.
