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// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_NUMERICS_SAFE_CONVERSIONS_ARM_IMPL_H_
#define BASE_NUMERICS_SAFE_CONVERSIONS_ARM_IMPL_H_
// IWYU pragma: private, include "base/numerics/safe_conversions.h"
#include <stdint.h>
#include <algorithm>
#include <concepts>
#include <type_traits>
#include "base/numerics/safe_conversions_impl.h"
namespace base {
namespace internal {
// Fast saturation to a destination type.
template <typename Dst, typename Src>
struct SaturateFastAsmOp {
static constexpr bool is_supported =
kEnableAsmCode && std::signed_integral<Src> && std::integral<Dst> &&
kIntegerBitsPlusSign<Src> <= kIntegerBitsPlusSign<int32_t> &&
kIntegerBitsPlusSign<Dst> <= kIntegerBitsPlusSign<int32_t> &&
!kIsTypeInRangeForNumericType<Dst, Src>;
__attribute__((always_inline)) static Dst Do(Src value) {
int32_t src = value;
if constexpr (std::is_signed_v<Dst>) {
int32_t result;
asm("ssat %[dst], %[shift], %[src]"
: [dst] "=r"(result)
: [src] "r"(src), [shift] "n"(
std::min(kIntegerBitsPlusSign<Dst>, 32)));
return static_cast<Dst>(result);
} else {
uint32_t result;
asm("usat %[dst], %[shift], %[src]"
: [dst] "=r"(result)
: [src] "r"(src), [shift] "n"(
std::min(kIntegerBitsPlusSign<Dst>, 31)));
return static_cast<Dst>(result);
}
}
};
} // namespace internal
} // namespace base
#endif // BASE_NUMERICS_SAFE_CONVERSIONS_ARM_IMPL_H_
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