pub unsafe extern "C" fn Hacl_Bignum64_sub_mod(
    len: u32,
    n: *mut u64,
    a: *mut u64,
    b: *mut u64,
    res: *mut u64
)
Expand description

Write (a - b) mod n in res.

The arguments a, b, n and the outparam res are meant to be len limbs in size, i.e. uint64_t[len].

Before calling this function, the caller will need to ensure that the following preconditions are observed. • a < n • b < n