Function core::arch::x86_64::_addcarry_u64

pub unsafe fn _addcarry_u64(c_in: u8, a: u64, b: u64, out: &mut u64) -> u8

This is supported on x86-64 only.

Adds unsigned 64-bit integers a and b with unsigned 8-bit carry-in c_in (carry flag), and store the unsigned 64-bit result in out, and the carry-out is returned (carry or overflow flag).