#region License
/* 
 * Copyright (C) 1999-2022 John Källén.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#endregion

using Reko.Core;
using Reko.Core.Expressions;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Text;

namespace Reko.Core.Rtl
{
    /// <summary>
    /// Models the `call`, `jsr` or similar machine code instructions.
    /// </summary>
    public sealed class RtlCall : RtlTransfer
    {
        /// <summary>
        /// Creates an <see cref="RtlCall"/> instruction.
        /// </summary>
        /// <remarks>
        /// Not only does this instruction model machine language subroutine calls,
        /// it also models transitions between different processor architectures.
        /// </remarks>
        /// <param name="target">The destination of the call.</param>
        /// <param name="stackPushedReturnAddressSize">If the processor pushes
        /// a return address on the stack, the size of that return address.</param>
        /// <param name="rtlClass">Instruction class of the call.</param>
        /// <param name="archSwitch">If non-null, the new architecture to switch to.</param>
        public RtlCall(
            Expression target,
            int stackPushedReturnAddressSize,
            InstrClass rtlClass,
            IProcessorArchitecture? arch = null) : base(target, rtlClass)
        {
            Debug.Assert((rtlClass & (InstrClass.Call | InstrClass.Transfer)) != 0);
            this.ReturnAddressSize = stackPushedReturnAddressSize;
            this.Architecture = arch;
        }

        /// <summary>
        /// If set, indicates the processor architecture to switch to.
        /// </summary>
        public IProcessorArchitecture? Architecture { get; }

        /// <summary>
        /// The size in bytes of the return address. Some architectures don't 
        /// pass the return address on the stack, but in a register. In those
        /// cases, this property should have the value 0.
        /// </summary>
        public int ReturnAddressSize { get; }

        public override T Accept<T>(RtlInstructionVisitor<T> visitor)
        {
            return visitor.VisitCall(this);
        }


        public override T Accept<T,C>(RtlInstructionVisitor<T,C> visitor, C context)
        {
            return visitor.VisitCall(this, context);
        }

        protected override void WriteInner(TextWriter writer)
        {
            if (Architecture != null)
                writer.Write("callx {0} {1} ({2})", Architecture.Name, Target, ReturnAddressSize);
            else
                writer.Write("call {0} ({1})", Target, ReturnAddressSize);
        }
    }
}