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diff --git a/externals/dynarmic/src/dynarmic/common/u128.cpp b/externals/dynarmic/src/dynarmic/common/u128.cpp
new file mode 100644
index 0000000000..dd78ac97ef
--- /dev/null
+++ b/externals/dynarmic/src/dynarmic/common/u128.cpp
@@ -0,0 +1,142 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2018 MerryMage
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#include "dynarmic/common/u128.h"
+
+#include <mcl/stdint.hpp>
+
+namespace Dynarmic {
+
+u128 Multiply64To128(u64 a, u64 b) {
+    const u32 a0 = static_cast<u32>(a);
+    const u32 b0 = static_cast<u32>(b);
+    const u32 a1 = static_cast<u32>(a >> 32);
+    const u32 b1 = static_cast<u32>(b >> 32);
+
+    // result = (c2 << 64) + (c1 << 32) + c0
+    // c2 = a1 * b1
+    // c1 = a1 * b0 + a0 * b1
+    // c0 = a0 * b0
+    // noting that these operations may overflow
+
+    const u64 c0 = static_cast<u64>(a0) * b0;
+    const u64 c1_0 = static_cast<u64>(a1) * b0;
+    const u64 c1_1 = static_cast<u64>(a0) * b1;
+    const u64 c2 = static_cast<u64>(a1) * b1;
+
+    const u64 c1 = c1_0 + c1_1;
+    const u64 c1_overflow = c1 < c1_0;
+
+    const u64 lower = c0 + (c1 << 32);
+    const u64 lower_overflow = lower < c0;
+
+    const u64 upper = lower_overflow + (c1 >> 32) + (c1_overflow << 32) + c2;
+
+    u128 result;
+    result.lower = lower;
+    result.upper = upper;
+    return result;
+}
+
+u128 operator<<(u128 operand, int amount) {
+    if (amount < 0) {
+        return operand >> -amount;
+    }
+
+    if (amount == 0) {
+        return operand;
+    }
+
+    if (amount < 64) {
+        u128 result;
+        result.lower = (operand.lower << amount);
+        result.upper = (operand.upper << amount) | (operand.lower >> (64 - amount));
+        return result;
+    }
+
+    if (amount < 128) {
+        u128 result;
+        result.upper = operand.lower << (amount - 64);
+        return result;
+    }
+
+    return {};
+}
+
+u128 operator>>(u128 operand, int amount) {
+    if (amount < 0) {
+        return operand << -amount;
+    }
+
+    if (amount == 0) {
+        return operand;
+    }
+
+    if (amount < 64) {
+        u128 result;
+        result.lower = (operand.lower >> amount) | (operand.upper << (64 - amount));
+        result.upper = (operand.upper >> amount);
+        return result;
+    }
+
+    if (amount < 128) {
+        u128 result;
+        result.lower = operand.upper >> (amount - 64);
+        return result;
+    }
+
+    return {};
+}
+
+u128 StickyLogicalShiftRight(u128 operand, int amount) {
+    if (amount < 0) {
+        return operand << -amount;
+    }
+
+    if (amount == 0) {
+        return operand;
+    }
+
+    if (amount < 64) {
+        u128 result;
+        result.lower = (operand.lower >> amount) | (operand.upper << (64 - amount));
+        result.upper = (operand.upper >> amount);
+        // Sticky bit
+        if ((operand.lower << (64 - amount)) != 0) {
+            result.lower |= 1;
+        }
+        return result;
+    }
+
+    if (amount == 64) {
+        u128 result;
+        result.lower = operand.upper;
+        // Sticky bit
+        if (operand.lower != 0) {
+            result.lower |= 1;
+        }
+        return result;
+    }
+
+    if (amount < 128) {
+        u128 result;
+        result.lower = operand.upper >> (amount - 64);
+        // Sticky bit
+        if (operand.lower != 0) {
+            result.lower |= 1;
+        }
+        if ((operand.upper << (128 - amount)) != 0) {
+            result.lower |= 1;
+        }
+        return result;
+    }
+
+    if (operand.lower != 0 || operand.upper != 0) {
+        return u128(1);
+    }
+    return {};
+}
+
+}  // namespace Dynarmic