using System;
using CPU = Indy.IL2CPU.Assembler;
using CPUx86 = Indy.IL2CPU.Assembler.X86;

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

    public override void Execute(uint aMethodUID, ILOpCode aOpCode) {
		  string xLabelName = AssemblerNasm.TmpPosLabel(aMethodUID, aOpCode);
      var xStackItem_ShiftAmount = OldAsmblr.StackContents.Pop();
      var xStackItem_Value = OldAsmblr.StackContents.Pop();
      if (xStackItem_Value.IsFloat) { 
        throw new NotImplementedException("Floats not yet supported!"); 
      }
      if (xStackItem_Value.Size <= 4) {
         new CPUx86.Pop{DestinationReg = CPUx86.Registers.EAX}; // shift amount
         new CPUx86.Pop { DestinationReg = CPUx86.Registers.EBX }; // value
         new CPUx86.Move { DestinationReg = CPUx86.Registers.CL, SourceReg = CPUx86.Registers.AL };
         new CPUx86.ShiftRight { DestinationReg = CPUx86.Registers.EBX, SourceReg=CPUx86.Registers.CL };
         new CPUx86.Push { DestinationReg = CPUx86.Registers.EBX };
         OldAsmblr.StackContents.Push(xStackItem_Value);
      } else if (xStackItem_Value.Size <= 8) {
         new CPUx86.Pop { DestinationReg = CPUx86.Registers.EDX };
         new CPUx86.Move { DestinationReg = CPUx86.Registers.EAX, SourceValue=0 };
         new CPU.Label(xLabelName + "__StartLoop");
         new CPUx86.Compare { DestinationReg = CPUx86.Registers.EDX, SourceReg=CPUx86.Registers.EAX};
         new CPUx86.ConditionalJump { Condition = CPUx86.ConditionalTestEnum.Equal, DestinationLabel = xLabelName + "__EndLoop" };
         new CPUx86.Move { DestinationReg = CPUx86.Registers.EBX, SourceReg = CPUx86.Registers.ESP, SourceIsIndirect=true };
         new CPUx86.Move { DestinationReg = CPUx86.Registers.CL, SourceValue = 1 };
         new CPUx86.ShiftRight { DestinationReg = CPUx86.Registers.EBX, SourceReg = CPUx86.Registers.CL };
         new CPUx86.Move { DestinationReg = CPUx86.Registers.ESP, DestinationIsIndirect=true, SourceReg = CPUx86.Registers.EBX };
         new CPUx86.Move { DestinationReg = CPUx86.Registers.CL, SourceValue = 1 };
         new CPUx86.RotateThroughCarryRight { DestinationReg = CPUx86.Registers.ESP, DestinationIsIndirect = true, DestinationDisplacement = 4, Size = 32, SourceReg=CPUx86.Registers.CL };
         new CPUx86.Add { DestinationReg = CPUx86.Registers.EAX, SourceValue = 1 };
         new CPUx86.Jump { DestinationLabel = xLabelName + "__StartLoop" };

         new CPU.Label(xLabelName + "__EndLoop");
         OldAsmblr.StackContents.Push(xStackItem_Value);
      }
    }
    
	}
}