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0 pointsEGreg7mo ago0 comments

From my college days, which were quite long ago. And working with Win32 "BitBlt" requests to the OS, etc.

And also, it would just make sense. If copying entire blocks or memory pages, such as "BitBlt", is one command, why would I need CPU cycles to actually do it? It would seem like the lowest hanging fruit to automate in SDRAM

It just seems like the easiest example of SIMD

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CyberDildonics7mo ago

These are contradictory things. SIMD instructions are still regular instructions, not some concurrent system for copying. When you say command, maybe you meant a windows OS function that was similar to memcpy. An OS function and individual CPU instructions are two different thing. There is something called DMA, but I don't know how much that is used for memory to memory copies.

EGregOP7mo ago

Well CPUs already transparently handle memory paging so why not copying?

https://en.wikipedia.org/wiki/Memory_paging

CyberDildonics7mo ago

I'm not making a case for anything I'm just explaining what exists. If copying were going to be done in bulk it would have to be done asynchronously to some extent, though CPUs already work like that on a small scale due to instruction reordering.

Now it might be less necessary because CPUs are so fast with contiguous data memory that copying to other parts of memory are less of a bottleneck.

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0 pointsEGreg7mo ago0 comments

From my college days, which were quite long ago. And working with Win32 "BitBlt" requests to the OS, etc.

It just seems like the easiest example of SIMD

0 comments

CyberDildonics7mo ago

EGregOP7mo ago

Well CPUs already transparently handle memory paging so why not copying?

https://en.wikipedia.org/wiki/Memory_paging

CyberDildonics7mo ago

Now it might be less necessary because CPUs are so fast with contiguous data memory that copying to other parts of memory are less of a bottleneck.

j / k navigate · click thread line to collapse