Cosmos/source/Cosmos.IL2CPU/IL/Conv_U2.cs

using System;
using Cosmos.Assembler.x86.SSE;
using XSharp.Compiler;
using CPUx86 = Cosmos.Assembler.x86;
using static XSharp.Compiler.XSRegisters;

namespace Cosmos.IL2CPU.X86.IL
{
	/// <summary>
	/// Convert top Stack element to UInt16 and extends it to Int32.
	/// </summary>
    [Cosmos.IL2CPU.OpCode( ILOpCode.Code.Conv_U2 )]
    public class Conv_U2 : ILOp
    {
        public Conv_U2( Cosmos.Assembler.Assembler aAsmblr )
            : base( aAsmblr )
        {
        }

        public override void Execute( MethodInfo aMethod, ILOpCode aOpCode )
        {
            var xSource = aOpCode.StackPopTypes[0];
            var xSourceSize = SizeOfType(xSource);
            if (TypeIsFloat(xSource))
            {
                if (xSourceSize == 4)
                {
                    XS.SSE.MoveSS(XMM0, ESP, sourceIsIndirect: true);
                    XS.SSE.ConvertSS2SIAndTruncate(EAX, XMM0);
                    XS.Set(ESP, EAX, destinationIsIndirect: true);
                }
                else if (xSourceSize == 8)
                {
                    XS.SSE2.MoveSD(XMM0, ESP, sourceIsIndirect: true);
                    XS.SSE2.ConvertSD2SIAndTruncate(EAX, XMM0);
                    // We need to move the stack pointer of 4 Byte to "eat" the second double that is yet in the stack or we get a corrupted stack!
                    XS.Add(ESP, 4);
                    XS.Set(ESP, EAX, destinationIsIndirect: true);
                }
                else
                {
                    throw new Exception("Cosmos.IL2CPU.x86->IL->Conv_U2.cs->Unknown size of floating point value.");
                }
            }
            else {
                switch( xSourceSize )
                {
                    case 2:
                        break;
                    case 1:
                    case 4:
						    XS.Pop(EAX);
						    XS.MoveZeroExtend(EAX, AX);
                            XS.Push(EAX);
						    break;
                    case 8:
                        {
                            XS.Pop(EAX);
                            XS.Pop(ECX);
                            XS.MoveZeroExtend(EAX, AX);
                            XS.Push(EAX);
                            break;
                        }
                    default:
                        //EmitNotImplementedException( Assembler, GetServiceProvider(), "Conv_U2: SourceSize " + xSource + " not yet supported!", mCurLabel, mMethodInformation, mCurOffset, mNextLabel );
                        throw new NotImplementedException("Cosmos.IL2CPU.x86->IL->Conv_U2.cs->Unknown size of variable on the top of the stack.");
                }
            }
        }
    }
}