using System;
using CPUx86 = Cosmos.Assembler.x86;
using CPU = Cosmos.Assembler.x86;
using Cosmos.Assembler.x86;
using Cosmos.Assembler;
using Cosmos.Assembler.x86.SSE;
using Cosmos.Assembler.x86.x87;

using XSharp.Common;
using static XSharp.Common.XSRegisters;
using static Cosmos.Assembler.x86.SSE.ComparePseudoOpcodes;

namespace Cosmos.IL2CPU.X86.IL
{
    [Cosmos.IL2CPU.OpCode( ILOpCode.Code.Clt_Un )]
    public class Clt_Un : ILOp
    {
        public Clt_Un( Cosmos.Assembler.Assembler aAsmblr )
            : base( aAsmblr )
        {
        }

        public override void Execute(_MethodInfo aMethod, ILOpCode aOpCode )
        {
            var xStackItem = aOpCode.StackPopTypes[0];
            var xStackItemSize = SizeOfType(xStackItem);
            var xStackItemIsFloat = TypeIsFloat(xStackItem);
            if( xStackItemSize > 8 )
            {
                throw new NotImplementedException("Cosmos.IL2CPU.x86->IL->Clt_Un.cs->Error: StackSizes > 8 not supported");
            }
            string BaseLabel = GetLabel( aMethod, aOpCode ) + ".";
            string LabelTrue = BaseLabel + "True";
            string LabelFalse = BaseLabel + "False";
            if (xStackItemSize > 4)
            {
                // Using SSE registers (that do NOT branch!) This is needed only for long now
#if false
				XS.Set(XSRegisters.ESI, 1);
				// esi = 1
				XS.Xor(XSRegisters.EDI, XSRegisters.EDI);
				// edi = 0
#endif
                if (xStackItemIsFloat)
                {
                    // Please note that SSE supports double operations only from version 2
                    XS.SSE2.MoveSD(XMM0, ESP, sourceIsIndirect: true);
                    // Increment ESP to get the value of the next double
                    XS.Add(ESP, 8);
                    XS.SSE2.MoveSD(XMM1, ESP, sourceIsIndirect: true);
                    XS.SSE2.CompareSD(XMM1, XMM0, comparision: LessThan);
                    XS.SSE2.MoveD(EBX, XMM1);
                    XS.And(EBX, 1);
                    // 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, EBX, destinationIsIndirect: true);
                }
                else
                {
                    XS.Set(ESI, 1);
                    // esi = 1
                    XS.Xor(EDI, EDI);
                    // edi = 0
                    XS.Pop(EAX);
                    XS.Pop(EDX);
                    //value2: EDX:EAX
                    XS.Pop(EBX);
                    XS.Pop(ECX);
                    //value1: ECX:EBX
                    XS.Sub(EBX, EAX);
                    XS.SubWithCarry(ECX, EDX);
                    //result = value1 - value2
                    new ConditionalMove { Condition = ConditionalTestEnum.Below, DestinationReg = RegistersEnum.EDI, SourceReg = RegistersEnum.ESI };
                    XS.Push(XSRegisters.EDI);
                }
            }
            else
            {
                if (xStackItemIsFloat)
                {
                    XS.Comment("TEST TODO");
                    XS.SSE.MoveSS(XMM0, ESP, sourceIsIndirect: true);
                    XS.Add(ESP, 4);
                    XS.SSE.MoveSS(XMM1, ESP, sourceIsIndirect: true);
                    XS.SSE.CompareSS(XMM1, XMM0, comparision: LessThan);
                    XS.SSE2.MoveD(EBX, XMM1);
                    XS.And(ESP, 1, destinationIsIndirect: true);
                    XS.Set(ESP, EBX, destinationIsIndirect: true);
                }
                else
                {
                    XS.Pop(ECX);
                    XS.Pop(XSRegisters.EAX);
                    XS.Push(XSRegisters.ECX);
                    XS.Compare(EAX, ESP, sourceIsIndirect: true);
                    XS.Jump(ConditionalTestEnum.Below, LabelTrue);
                    XS.Jump(LabelFalse);
                    XS.Label(LabelTrue);
                    XS.Add(XSRegisters.ESP, 4);
                    XS.Push(1);
                    new Jump { DestinationLabel = GetLabel(aMethod, aOpCode.NextPosition) };
                    XS.Label(LabelFalse);
                    XS.Add(XSRegisters.ESP, 4);
                    XS.Push(0);
                }
            }
        }
    }
}