# Kernel/RtlExtendedLargeIntegerDivide

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RtlExtendedLargeIntegerDivide will call RtlRaiseStatus(STATUS_INTEGER_DIVIDE_BY_ZERO) if Divisor = 0. Otherwise, a custom binary division algorithm is used to perform the divide operation. The algorithm below was reverse engineered from original hardware.

LARGE_INTEGER quotient = Dividend; ULONG local_remainder = 0; BOOLEAN carry, remainder_carry; for (uint8_t i = 64; i > 0; i--) { carry = (quotient.QuadPart >> 63) & 0x1; remainder_carry = (local_remainder >> 31) & 0x1; quotient.QuadPart <<= 1; local_remainder = (local_remainder << 1) | carry; if (remainder_carry || (local_remainder >= Divisor)) { quotient.u.LowPart += 1; local_remainder -= Divisor; } } if (Remainder) { *Remainder = local_remainder; }