/*
 * Copyright 2020 Google Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * 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;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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 THE COPYRIGHT
 * OWNER 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.
 */

#ifndef __ARCH_ARM_REG_ABI_HH__
#define __ARCH_ARM_REG_ABI_HH__

#include <vector>

#include "base/logging.hh"
#include "sim/syscall_abi.hh"

namespace ArmISA
{

struct RegABI32 : public GenericSyscallABI32
{
    static const std::vector<int> ArgumentRegs;
};

struct RegABI64 : public GenericSyscallABI64
{
    static const std::vector<int> ArgumentRegs;
};

} // namespace ArmISA

namespace GuestABI
{

template <typename ABI, typename Arg>
struct Argument<ABI, Arg,
    typename std::enable_if_t<
        std::is_base_of<ArmISA::RegABI32, ABI>::value &&
        std::is_integral<Arg>::value &&
        ABI::template IsWide<Arg>::value>>
{
    static Arg
    get(ThreadContext *tc, typename ABI::State &state)
    {
        // 64 bit arguments are passed starting in an even register.
        if (state % 2)
            state++;
        panic_if(state + 1 >= ABI::ArgumentRegs.size(),
                "Ran out of syscall argument registers.");
        auto low = ABI::ArgumentRegs[state++];
        auto high = ABI::ArgumentRegs[state++];
        return (Arg)ABI::mergeRegs(tc, low, high);
    }
};

} // namespace GuestABI

#endif // __ARCH_ARM_GEM5_OP_HH__