Function safe_arch::add_carry_u64

pub fn add_carry_u64(c_in: u8, a: u64, b: u64, out: &mut u64) -> u8

This is supported with target feature adx only.

Add two u64 with a carry value.

Writes the sum to the reference and returns the new carry flag.

let mut out = 0_u64;
assert_eq!(add_carry_u64(1, u64::MAX, 5, &mut out), 1);
assert_eq!(out, 5);