--- /dev/null
+++ dyld/dyld-1340/lsl/PVLEInt64.cpp
@@ -0,0 +1,75 @@
+/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
+ *
+ * Copyright (c) 2021 Apple Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+#include <TargetConditionals.h>
+
+#if !TARGET_OS_EXCLAVEKIT
+
+#include <bit>
+
+#include "Defines.h"
+#include "BitUtils.h"
+#include "PVLEInt64.h"
+
+namespace lsl {
+void emitPVLEUInt64(uint64_t value, Vector<std::byte>& data) {
+    auto valueBytes = (std::byte*)&value;
+    const uint8_t activeBits = std::max<uint8_t>(lsl::bit_width(value),1);
+    if (activeBits > 56) {
+        data.push_back((std::byte)0);
+        std::copy(&valueBytes[0], &valueBytes[8], std::back_inserter(data));
+        return;
+    }
+    const uint8_t bytes = (activeBits+6)/7;
+    value <<= bytes;
+    value |= 1<<(bytes-1);
+    std::copy(&valueBytes[0], &valueBytes[bytes], std::back_inserter(data));
+}
+
+bool readPVLEUInt64(std::span<std::byte>& data, uint64_t& result) {
+    result = 0;
+    if (data.size() == 0) {
+        return false;
+    }
+    const uint8_t additionalByteCount = std::countr_zero((uint8_t)data[0]);
+    if (data.size() < additionalByteCount+1) {
+        return false;
+    }
+    if (additionalByteCount == 8) {
+        std::copy(data.begin()+1, data.begin()+9, (std::byte*)&result);
+        data = data.last(data.size()-9);
+        return true;
+    }
+    const uint8_t extraBitCount     = 8 - (additionalByteCount+1);
+    const uint8_t extraBits         = (((uint8_t)(data[0]))>>(additionalByteCount+1)) & ((1<<extraBitCount)-1);
+    std::copy(data.begin()+1, data.begin()+additionalByteCount+1, (std::byte*)&result);
+    result <<= extraBitCount;
+    result |= extraBits;
+    data = data.last(data.size()-(additionalByteCount+1));
+    return true;
+}
+
+};
+
+#endif // !TARGET_OS_EXCLAVEKIT