but if you have a single bool in a stack frame it’s probably going to be more than a byte.
Nope. - if you can’t read RISC-V assembly, look at these lines
sb a5,-17(s0)
...
sb a5,-18(s0)
...
sb a5,-19(s0)
...
That is it storing the bools in single bytes. Also I only used RISC-V because I’m way more familiar with it than x86, but it will do the same thing.
on the heap definitely more than a byte
Nope, you can happily malloc(1)
and store a bool in it, or malloc(4)
and store 4 bools in it. A bool is 1 byte. Consider this a TIL moment.
Wrong again. It depends on the CPU. They can absolutely read a single byte and they will do if you’re reading from non-idempotent memory.
If you’re reading from idempotent memory they won’t read a byte or a word. They’ll likely read a whole cache line (usually 64 bytes).
Where?
No they won’t because it isn’t faster. The CPU will read the whole cache line that contains the byte.
Well, I would but no manual says that because it’s wrong!