From 3ea48e8ebe25686f2342cd79b32409fcd1bccb28 Mon Sep 17 00:00:00 2001 From: Fernando Sahmkow Date: Fri, 15 Feb 2019 19:26:41 -0400 Subject: Implement 128 bits Unsigned Integer Multiplication and Division. --- src/common/uint128.cpp | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 src/common/uint128.cpp (limited to 'src/common/uint128.cpp') diff --git a/src/common/uint128.cpp b/src/common/uint128.cpp new file mode 100644 index 000000000..aea7f03e2 --- /dev/null +++ b/src/common/uint128.cpp @@ -0,0 +1,18 @@ + +namespace Common { + +std::pair udiv128(u128 dividend, u64 divisor) { + u64 remainder = dividend[0] % divisor; + u64 accum = dividend[0] / divisor; + if (dividend[1] == 0) + return {accum, remainder}; + // We ignore dividend[1] / divisor as that overflows + u64 first_segment = (dividend[1] % divisor) << 32; + accum += (first_segment / divisor) << 32; + u64 second_segment = (first_segment % divisor) << 32; + accum += (second_segment / divisor); + remainder += second_segment % divisor; + return {accum, remainder}; +} + +} // namespace Common -- cgit v1.2.3