using System;
using CPUx86 = Cosmos.Compiler.Assembler.X86;
using Cosmos.Compiler.Assembler;
using Cosmos.IL2CPU.IL.CustomImplementations.System;
namespace Cosmos.IL2CPU.X86.IL
{
    [Cosmos.IL2CPU.OpCode( ILOpCode.Code.Ldelem_Ref )]
    public class Ldelem_Ref : ILOp
    {
        public Ldelem_Ref( Cosmos.Compiler.Assembler.Assembler aAsmblr )
            : base( aAsmblr )
        {
        }
        public static void Assemble( Assembler aAssembler, uint aElementSize )
        {
            new CPUx86.Pop { DestinationReg = CPUx86.Registers.EAX };
            new CPUx86.Move { DestinationReg = CPUx86.Registers.EDX, SourceValue = aElementSize };
            new CPUx86.Multiply { DestinationReg = CPUx86.Registers.EDX };

            //TODO: implement ObjectImpl first
            new CPUx86.Add { DestinationReg = CPUx86.Registers.EAX, SourceValue = ( ObjectImpl.FieldDataOffset + 4 ) };

            new CPUx86.Pop { DestinationReg = CPUx86.Registers.EDX };
            new CPUx86.Add { DestinationReg = CPUx86.Registers.EDX, SourceReg = CPUx86.Registers.EAX };
            new CPUx86.Move { DestinationReg = CPUx86.Registers.EAX, SourceReg = CPUx86.Registers.EDX };
            uint xSizeLeft = aElementSize;
            while( xSizeLeft > 0 )
            {
                if( xSizeLeft >= 4 )
                {
                    new CPUx86.Push { DestinationReg = CPUx86.Registers.EAX, DestinationIsIndirect = true };
                    new CPUx86.Add { DestinationReg = CPUx86.Registers.EAX, SourceValue = 4 };
                    xSizeLeft -= 4;
                }
                else
                {
                    if( xSizeLeft >= 2 )
                    {
                        new CPUx86.Move { DestinationReg = CPUx86.Registers.ECX, SourceValue = 0 };
                        new CPUx86.Move { DestinationReg = CPUx86.Registers.CX, SourceReg = CPUx86.Registers.EAX, SourceIsIndirect = true };
                        new CPUx86.Push { DestinationReg = CPUx86.Registers.ECX };
                        new CPUx86.Add { DestinationReg = CPUx86.Registers.EAX, SourceValue = 2 };
                        xSizeLeft -= 2;
                    }
                    else
                    {
                        if( xSizeLeft >= 1 )
                        {
                            new CPUx86.Move { DestinationReg = CPUx86.Registers.ECX, SourceValue = 0 };
                            new CPUx86.Move { DestinationReg = CPUx86.Registers.CL, SourceReg = CPUx86.Registers.EAX, SourceIsIndirect = true };
                            new CPUx86.Push { DestinationReg = CPUx86.Registers.ECX };
                            new CPUx86.Add { DestinationReg = CPUx86.Registers.EAX, SourceValue = 1 };
                            xSizeLeft -= 1;
                        }
                        else
                        {
                            throw new Exception( "Size left: " + xSizeLeft );
                        }
                    }
                }
            }
            aAssembler.Stack.Pop();
            aAssembler.Stack.Pop();
#if DOTNETCOMPATIBLE
            aAssembler.Stack.Push(ILOp.Align(aElementSize, 4), typeof(uint)); //TODO typeof type if aElementsize is other then 4
#else
			aAssembler.Stack.Push(aElementSize, typeof(uint));
#endif
        }

        public override void Execute( MethodInfo aMethod, ILOpCode aOpCode )
        {
            Assemble( Assembler, 4 );
        }
    }
}