Linus Torvalds writes: (Summary) Just looking at this patch, my reaction was "why isn't this
an 'andl $~X86_EFLAGS_IF' instead"?
an 'andl $~X86_EFLAGS_IF' instead"?
Yeah, I guess the 'andl' is two bytes longer (due to the 32-bit constant - because IF is bit 9, you can't use a byte constant, and you don't want to get a partial word write just before the popfl). But btr is really pretty heavy operation for older CPU's (it's gotten better, but 32-bit code presumably cares more about the older CPUs). Andy?
Andy?
Linus
Linus
Linus
an 'andl $~X86_EFLAGS_IF' instead"?
Yeah, I guess the 'andl' is two bytes longer (due to the 32-bit constant - because IF is bit 9, you can't use a byte constant, and you don't want to get a partial word write just before the popfl). But btr is really pretty heavy operation for older CPU's (it's gotten better, but 32-bit code presumably cares more about the older CPUs). Andy?
Andy?
Linus
Linus
Linus