On Mon, Mar 16, 2009 at 3:29 PM, BCS <n...@anon.com> wrote: >> I'm actually kind of shocked that given the prevalence of memory block >> copy operations that more CPUs haven't implemented it as a basic >> instruction. Yes, RISC is nice, but geez, this seems like a >> no-brainer. >> > > How about memory to memory DMA, Why even make the CPU wait for it to finish?
Sure, then you have to worry about waiting for the *DMA* to finish. If it's a copy whose result is largely unimportant to the immediately-following code (copying a backbuffer into a frontbuffer, for example), it doesn't matter. But for copying large value types, I'd think it's pretty important that the copy is semantically atomic.
