4 ms·
The prefixes are redundant so it's not really case-by-case behavior. You're just repeating the prefix you would be using anyway in that location. Using special
by epcoa 3y ago
The prefixes are redundant so it's not really case-by-case behavior. You're just repeating the prefix you would be using anyway in that location.
Using specialized prefixes wastes encoding space for no real gain.
You realize on most common processors NOP itself is a pseudo-instruction? Even the apparently meme-worthy (see sibling comment) RISC-V, it's ADDI x0, x0, 0.
- tedunangst 3y agoAnd then there are CPUs that retcon behavioral changes onto nops. > Moving a register to itself is functionally a nop, but the processor overloads it to signal information about priority. https://devblogs.microsoft.com/oldnewthing/20180809-00/?p=99455 https://devblogs.microsoft.com/oldnewthing/20180809-00/?p=99...
- _a_a_a_ 3y ago> A program can voluntarily set itself to low priority if it is waiting for a spin lock What does this even mean? How can a program do this when thread priority is an OS thing? It's seems just weird.
- epcoa 3y agoHardware threads as in SMT means thread priority is also a hardware thing.
- tedunangst 3y agoIt's an SMT CPU that dynamically assigns decode, registers, etc. https://course.ece.cmu.edu/~ece740/f13/lib/exe/fetch.php?media=kalla04_power5.pdf https://course.ece.cmu.edu/~ece740/f13/lib/exe/fetch.php?med...