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diff --git a/deps/v8/src/base/safe_conversions_arm_impl.h b/deps/v8/src/base/safe_conversions_arm_impl.h
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+++ b/deps/v8/src/base/safe_conversions_arm_impl.h
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+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Slightly adapted for inclusion in V8.
+// Copyright 2014 the V8 project authors. All rights reserved.
+// List of adaptations:
+// - include guard names
+// - wrap in v8 namespace
+// - include paths
+
+#ifndef V8_BASE_SAFE_CONVERSIONS_ARM_IMPL_H_
+#define V8_BASE_SAFE_CONVERSIONS_ARM_IMPL_H_
+
+#include <cassert>
+#include <limits>
+#include <type_traits>
+
+#include "src/base/safe_conversions_impl.h"
+
+namespace v8 {
+namespace base {
+namespace internal {
+
+// Fast saturation to a destination type.
+template <typename Dst, typename Src>
+struct SaturateFastAsmOp {
+ static constexpr bool is_supported =
+ std::is_signed<Src>::value && std::is_integral<Dst>::value &&
+ std::is_integral<Src>::value &&
+ IntegerBitsPlusSign<Src>::value <= IntegerBitsPlusSign<int32_t>::value &&
+ IntegerBitsPlusSign<Dst>::value <= IntegerBitsPlusSign<int32_t>::value &&
+ !IsTypeInRangeForNumericType<Dst, Src>::value;
+
+ __attribute__((always_inline)) static Dst Do(Src value) {
+ int32_t src = value;
+ typename std::conditional<std::is_signed<Dst>::value, int32_t,
+ uint32_t>::type result;
+ if (std::is_signed<Dst>::value) {
+ asm("ssat %[dst], %[shift], %[src]"
+ : [dst] "=r"(result)
+ : [src] "r"(src), [shift] "n"(IntegerBitsPlusSign<Dst>::value <= 32
+ ? IntegerBitsPlusSign<Dst>::value
+ : 32));
+ } else {
+ asm("usat %[dst], %[shift], %[src]"
+ : [dst] "=r"(result)
+ : [src] "r"(src), [shift] "n"(IntegerBitsPlusSign<Dst>::value < 32
+ ? IntegerBitsPlusSign<Dst>::value
+ : 31));
+ }
+ return static_cast<Dst>(result);
+ }
+};
+
+} // namespace internal
+} // namespace base
+} // namespace v8
+
+#endif // V8_BASE_SAFE_CONVERSIONS_ARM_IMPL_H_