λ x x0 : word64 * word64 * word64 * word64 * word64,
Interp-η
(λ var : Syntax.base_type → Type,
 λ '(x10, x11, x9, x7, x5, (x18, x19, x17, x15, x13))%core,
 (((0x3ffffffffffffe + x10) - x18), ((0x3ffffffffffffe + x11) - x19), ((0x3ffffffffffffe + x9) - x17), ((0x3ffffffffffffe + x7) - x15), ((0x7ffffffffffffa + x5) - x13)))
(x, x0)%core
     : word64 * word64 * word64 * word64 * word64 → word64 * word64 * word64 * word64 * word64 → ReturnType (uint64_t * uint64_t * uint64_t * uint64_t * uint64_t)