On 11/23/2010 8:13 PM, Johann MacDonagh wrote:
Did you try the inline ASM block without explicit register preservation?
Walter replied to your message before
(http://www.digitalmars.com/d/archives/digitalmars/D/Register_Preservation_in_Inline_ASM_Blocks_122470.html)
and said the compiler will work around any registers you use in inline
blocks. I tested it out and I can confirm he wasn't lying ;)
I'm not by a machine with dmd otherwise I'd try myself. Try removing the
explicit push/pops of the registers and use ecx instead of ebx in the
second diff (use of it forces dmd to push ebx in the prologue because
its callee save). Might save a considerable amount of cycles.
Ah nvm. Results in a 6% or so savings. It's definitely the lock prefix
slowing it down.
Mostly OT, what was the rationale for requiring the lock prefix being a
separate statement in inline ASM? NASM and MASM keep it inline with the
statement it affects.
