3 ms·
I remember Andy Glew discussing a little bit of the history of the behaviour of REP MOVS microcode in the comments of this stack overflow question http://stacko
by fsfod 10y ago
I remember Andy Glew discussing a little bit of the history of the behaviour of REP MOVS microcode in the comments of this stack overflow question http://stackoverflow.com/questions/8858778/why-are-complicated-memcpy-memset-superior/9177369#9177369 http://stackoverflow.com/questions/8858778/why-are-complicat...
- wscott 10y agoYup, we spend a bunch of time trying different options. But they never gave Andy the uop he really wanted which would zero the next cache line. Normally when you start writing to memory the machine will populate the cache line to be written from memory. He wanted the ability to say he plans on writing the whole thing so don't bother and if something happens then assume it is all zeros. (or something like that) Perhaps the current machines have this now... but probably not.