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/*
* Copyright (C) 2016 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "CPU.h"
#include <wtf/StdLibExtras.h>
namespace JSC {
#if USE(JSVALUE64)
// According to C++ rules, a type used for the return signature of function with C linkage (i.e.
// 'extern "C"') needs to be POD; hence putting any constructors into it could cause either compiler
// warnings, or worse, a change in the ABI used to return these types.
struct UGPRPair {
UCPURegister first;
UCPURegister second;
};
static_assert(sizeof(UGPRPair) == sizeof(UCPURegister) * 2, "UGPRPair should fit in two machine registers");
constexpr UGPRPair makeUGPRPair(UCPURegister first, UCPURegister second) { return { first, second }; }
inline UGPRPair encodeResult(const void* a, const void* b)
{
return makeUGPRPair(reinterpret_cast<UCPURegister>(a), reinterpret_cast<UCPURegister>(b));
}
inline void decodeResult(UGPRPair result, const void*& a, const void*& b)
{
a = reinterpret_cast<void*>(result.first);
b = reinterpret_cast<void*>(result.second);
}
inline void decodeResult(UGPRPair result, size_t& a, size_t& b)
{
a = static_cast<size_t>(result.first);
b = static_cast<size_t>(result.second);
}
#else // USE(JSVALUE32_64)
using UGPRPair = uint64_t;
#if CPU(BIG_ENDIAN)
constexpr UGPRPair makeUGPRPair(UCPURegister first, UCPURegister second) { return static_cast<uint64_t>(first) << 32 | second; }
#else
constexpr UGPRPair makeUGPRPair(UCPURegister first, UCPURegister second) { return static_cast<uint64_t>(second) << 32 | first; }
#endif
typedef union {
struct {
const void* a;
const void* b;
} pair;
uint64_t i;
} UGPRPairEncoding;
inline UGPRPair encodeResult(const void* a, const void* b)
{
return makeUGPRPair(reinterpret_cast<UCPURegister>(a), reinterpret_cast<UCPURegister>(b));
}
inline void decodeResult(UGPRPair result, const void*& a, const void*& b)
{
UGPRPairEncoding u;
u.i = result;
a = u.pair.a;
b = u.pair.b;
}
inline void decodeResult(UGPRPair result, size_t& a, size_t& b)
{
UGPRPairEncoding u;
u.i = result;
a = std::bit_cast<size_t>(u.pair.a);
b = std::bit_cast<size_t>(u.pair.b);
}
#endif // USE(JSVALUE32_64)
} // namespace JSC
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