I'm trying to figure out how to use codecopy in yul, but I can't see how to get the start position

there's some overhead with solidity converting the data into a bytes array that isn't necessary for what I'm trying to do, which is just to read a couple of bytes at a time from the constant

either way, regardless of my use case, there's an opcode in yul that seems impossible to use?

I'm just using a constant as an example, but in general I can't see how to use codecopy in any way

Codecopys syntax is pretty straightforward isn't it?

codecopy(destination,codeoffset, length)

but there's no way to know the codeoffset

solc clearly knows the offset or constants wouldn't work at all

but I can't seem to get at it