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-rw-r--r--src/common/uint128.cpp11
-rw-r--r--src/common/uint128.h9
2 files changed, 11 insertions, 9 deletions
diff --git a/src/common/uint128.cpp b/src/common/uint128.cpp
index 8548ba808..2238a52c5 100644
--- a/src/common/uint128.cpp
+++ b/src/common/uint128.cpp
@@ -3,31 +3,32 @@
#pragma intrinsic(_umul128)
#endif
+#include <cstring>
#include "common/uint128.h"
namespace Common {
+
u128 Multiply64Into128(u64 a, u64 b) {
-#ifdef _MSC_VER
u128 result;
+#ifdef _MSC_VER
result[0] = _umul128(a, b, &result[1]);
#else
unsigned __int128 tmp = a;
tmp *= b;
- u128 result;
std::memcpy(&result, &tmp, sizeof(u128));
#endif
return result;
}
-std::pair<u64, u64> Divide128On64(u128 dividend, u64 divisor) {
+std::pair<u64, u64> Divide128On32(u128 dividend, u32 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;
+ const u64 first_segment = (dividend[1] % divisor) << 32;
accum += (first_segment / divisor) << 32;
- u64 second_segment = (first_segment % divisor) << 32;
+ const u64 second_segment = (first_segment % divisor) << 32;
accum += (second_segment / divisor);
remainder += second_segment % divisor;
if (remainder >= divisor) {
diff --git a/src/common/uint128.h b/src/common/uint128.h
index 45e384c33..52e6b46eb 100644
--- a/src/common/uint128.h
+++ b/src/common/uint128.h
@@ -1,13 +1,14 @@
-#include <array>
-#include <cstdint>
-#include <cstring>
+
#include <utility>
#include "common/common_types.h"
namespace Common {
+// This function multiplies 2 u64 values and produces a u128 value;
u128 Multiply64Into128(u64 a, u64 b);
-std::pair<u64, u64> Divide128On64(u128 dividend, u64 divisor);
+// This function divides a u128 by a u32 value and produces two u64 values:
+// the result of division and the remainder
+std::pair<u64, u64> Divide128On32(u128 dividend, u32 divisor);
} // namespace Common