There isn't any pure C code you can write which would be expressed with those instructions, in the sort of way that MUL would be an expression of "a * b" (for e

There isn't any pure C code you can write which would be expressed with those instructions, in the sort of way that MUL would be an expression of "a * b" (for example). The C virtual machine doesn't have the concept of an I/O port or a global descriptor table; the only way of interacting with these features from C is to either use a CPU-specific intrinsic (not available for these instructions) or inline assembly.