Function align_stack_pointer 

pub fn align_stack_pointer(pointer: u64) -> u64

Aligns the stack pointer to be 16 byte aligned, and then misaligns it by 8 bytes.

This is done because x86-64 functions expect the stack to be misaligned by 8 bytes, as if the stack was 16 byte aligned and then someone used a call instruction. This is due to alignment-requiring SSE instructions.