λ x x0 : word128 * word128,
Interp-η
(λ var : Syntax.base_type → Type,
 λ '(x4, x5, (x6, x7))%core,
 uint128_t x9, uint8_t x10 = subborrow_u128(0x0, x5, x7);
 uint128_t x12, uint8_t x13 = subborrow_u128(x10, x4, x6);
 uint128_t x14 = (uint128_t)cmovznz(x13, 0x0, 0xffffffffffffffffffffffffffffffffL);
 uint128_t x15 = x14 & 0xffffffffffffffffffffffffL;
 uint128_t x17, uint8_t x18 = addcarryx_u128(0x0, x9, x15);
 uint128_t x19 = x14 & 0xffffffff000000010000000000000000L;
 uint128_t x21, uint8_t _ = addcarryx_u128(x18, x12, x19);
 (Return x21, Return x17))
(x, x0)%core
     : word128 * word128 → word128 * word128 → ReturnType (uint128_t * uint128_t)