λ x : word64 * word64 * word64 * word64 * word64,
Interp-η
(λ var : Syntax.base_type → Type,
 λ '(x7, x8, x6, x4, x2)%core,
 uint128_t x9 = ((((uint128_t)x2 * x7) + ((0x2 * ((uint128_t)x4 * x8)) + (((uint128_t)x6 * x6) + ((0x2 * ((uint128_t)x8 * x4)) + ((uint128_t)x7 * x2))))) + (0x4000000 * ((uint128_t)x7 * x7)));
 uint128_t x10 = ((((uint128_t)x2 * x8) + (((uint128_t)x4 * x6) + (((uint128_t)x6 * x4) + ((uint128_t)x8 * x2)))) + (((uint128_t)x7 * x7) + (0x2000000 * ((0x2 * ((uint128_t)x8 * x7)) + (0x2 * ((uint128_t)x7 * x8))))));
 uint128_t x11 = ((((uint128_t)x2 * x6) + ((0x2 * ((uint128_t)x4 * x4)) + ((uint128_t)x6 * x2))) + (((0x2 * ((uint128_t)x8 * x7)) + (0x2 * ((uint128_t)x7 * x8))) + (0x4000000 * (((uint128_t)x6 * x7) + ((0x2 * ((uint128_t)x8 * x8)) + ((uint128_t)x7 * x6))))));
 uint128_t x12 = ((((uint128_t)x2 * x4) + ((uint128_t)x4 * x2)) + ((((uint128_t)x6 * x7) + ((0x2 * ((uint128_t)x8 * x8)) + ((uint128_t)x7 * x6))) + (0x2000000 * ((0x2 * ((uint128_t)x4 * x7)) + ((0x2 * ((uint128_t)x6 * x8)) + ((0x2 * ((uint128_t)x8 * x6)) + (0x2 * ((uint128_t)x7 * x4))))))));
 uint128_t x13 = (((uint128_t)x2 * x2) + ((0x2 * ((uint128_t)x4 * x7)) + ((0x2 * ((uint128_t)x6 * x8)) + ((0x2 * ((uint128_t)x8 * x6)) + (0x2 * ((uint128_t)x7 * x4))))));
 uint64_t x14 = (uint64_t) (x13 >> 0x27);
 uint64_t x15 = ((uint64_t)x13 & 0x7fffffffff);
 uint128_t x16 = (x9 >> 0x26);
 uint64_t x17 = ((uint64_t)x9 & 0x3fffffffff);
 uint128_t x18 = ((0x4000000000 * x16) + x17);
 uint128_t x19 = (x18 >> 0x26);
 uint64_t x20 = ((uint64_t)x18 & 0x3fffffffff);
 uint128_t x21 = ((x14 + x12) + (0x2000000 * x19));
 uint128_t x22 = (x21 >> 0x26);
 uint64_t x23 = ((uint64_t)x21 & 0x3fffffffff);
 uint128_t x24 = (x15 + x19);
 uint64_t x25 = (uint64_t) (x24 >> 0x27);
 uint64_t x26 = ((uint64_t)x24 & 0x7fffffffff);
 uint128_t x27 = (x22 + x11);
 uint128_t x28 = (x27 >> 0x27);
 uint64_t x29 = ((uint64_t)x27 & 0x7fffffffff);
 uint128_t x30 = (x28 + x10);
 uint128_t x31 = (x30 >> 0x26);
 uint64_t x32 = ((uint64_t)x30 & 0x3fffffffff);
 uint128_t x33 = (x31 + x20);
 uint64_t x34 = (uint64_t) (x33 >> 0x26);
 uint64_t x35 = ((uint64_t)x33 & 0x3fffffffff);
 uint128_t x36 = (((uint128_t)0x4000000000 * x34) + x35);
 uint64_t x37 = (uint64_t) (x36 >> 0x26);
 uint64_t x38 = ((uint64_t)x36 & 0x3fffffffff);
 uint64_t x39 = ((x25 + x23) + (0x2000000 * x37));
 uint64_t x40 = (x39 >> 0x26);
 uint64_t x41 = (x39 & 0x3fffffffff);
 uint64_t x42 = (x26 + x37);
 uint64_t x43 = (x42 >> 0x27);
 uint64_t x44 = (x42 & 0x7fffffffff);
 return (Return x38, Return x32, (x40 + x29), (x43 + x41), Return x44))
x
     : word64 * word64 * word64 * word64 * word64 → ReturnType (uint64_t * uint64_t * uint64_t * uint64_t * uint64_t)