Suspect this line: uint32_t y = ((UINT64_C(0x640a0100) * digits.as_int)>>32)&0xff; This makes assumptions about how a 64-bit int is laid out in memory. Not

Suspect this line: uint32_t y = ((UINT64_C(0x640a0100) * digits.as_int)>>32)&0xff; This makes assumptions about how a 64-bit int is laid out in memory. Not near a big endian system right now (I know, right?) but I'm pretty sure this is the problem.