// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;

namespace Microsoft.Diagnostics.DataContractReader.Contracts.GCInfoHelpers;

internal class ARM64GCInfoTraits : IGCInfoTraits
{
    public static uint DenormalizeStackBaseRegister(uint reg) => reg ^ 29u;
    public static uint DenormalizeCodeLength(uint len) => len << 2;
    public static uint NormalizeCodeLength(uint len) => len >> 2;
    public static uint DenormalizeCodeOffset(uint offset) => offset << 2;
    public static uint NormalizeCodeOffset(uint offset) => offset >> 2;
    public static int DenormalizeStackSlot(int x) => x << 3;
    public static uint DenormalizeSizeOfStackArea(uint size) => size << 3;

    public static int GENERICS_INST_CONTEXT_STACK_SLOT_ENCBASE => 6;

    public static int GS_COOKIE_STACK_SLOT_ENCBASE => 6;
    public static int CODE_LENGTH_ENCBASE => 8;

    public static int STACK_BASE_REGISTER_ENCBASE => 2;
    public static int SIZE_OF_STACK_AREA_ENCBASE => 3;
    public static int SIZE_OF_EDIT_AND_CONTINUE_PRESERVED_AREA_ENCBASE => 4;
    public static int SIZE_OF_EDIT_AND_CONTINUE_FIXED_STACK_FRAME_ENCBASE => 4;
    public static int REVERSE_PINVOKE_FRAME_ENCBASE => 6;
    public static int NUM_REGISTERS_ENCBASE => 3;
    public static int NUM_STACK_SLOTS_ENCBASE => 2;
    public static int NUM_UNTRACKED_SLOTS_ENCBASE => 1;
    public static int NORM_PROLOG_SIZE_ENCBASE => 5;
    public static int NORM_EPILOG_SIZE_ENCBASE => 3;
    public static int INTERRUPTIBLE_RANGE_DELTA1_ENCBASE => 6;
    public static int INTERRUPTIBLE_RANGE_DELTA2_ENCBASE => 6;
    public static int REGISTER_ENCBASE => 3;
    public static int REGISTER_DELTA_ENCBASE => 2;
    public static int STACK_SLOT_ENCBASE => 6;
    public static int STACK_SLOT_DELTA_ENCBASE => 4;
    public static int NUM_SAFE_POINTS_ENCBASE => 3;
    public static int NUM_INTERRUPTIBLE_RANGES_ENCBASE => 1;

    public static bool HAS_FIXED_STACK_PARAMETER_SCRATCH_AREA => true;

    // Preserved (non-scratch): x19-x28
    // Scratch: x0-x17, x29(FP), x30(LR)
    public static bool IsScratchRegister(uint regNum) => regNum <= 17 || regNum >= 29;

    // ARM64 has a fixed stack parameter scratch area.
    // Stack slots with GC_SP_REL base in [0, scratchAreaSize) are scratch slots.
    public static bool IsScratchStackSlot(int spOffset, uint spBase, uint fixedStackParameterScratchArea)
    {
        // GC_SP_REL = 1
        return spBase == 1
            && spOffset >= 0
            && (uint)spOffset < fixedStackParameterScratchArea;
    }
}