memcpy vs slice copy

[Don]

BCS wrote:
> Hello Jarrett,
> 
>> 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?
> 
> 
That actually happens, to some extent, on some CPUs. If you get 
everything right, the data only goes to the outermost cache, and never 
reaches the CPU itself.