src/arch/arm/reg_abi.hh

/*
 * Copyright 2020 Google Inc.
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#ifndef __ARCH_ARM_REG_ABI_HH__
#define __ARCH_ARM_REG_ABI_HH__

#include <vector>

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

namespace gem5
{

namespace ArmISA
{

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

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

} // namespace ArmISA

GEM5_DEPRECATED_NAMESPACE(GuestABI, guest_abi);
namespace guest_abi
{

template <typename ABI, typename Arg>
struct Argument<ABI, Arg,
    typename std::enable_if_t<
        std::is_base_of_v<ArmISA::RegABI32, ABI> &&
        std::is_integral_v<Arg> &&
        ABI::template IsWideV<Arg>>>
{
    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 guest_abi
} // namespace gem5

#endif // __ARCH_ARM_REG_ABI_HH__