Cosmos/source/Indy.IL2CPU/IL/x86/Cgt.cs

using System;
using System.IO;


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

namespace Indy.IL2CPU.IL.X86 {
	[OpCode(OpCodeEnum.Cgt)]
	public class Cgt: Op {
		private readonly string NextInstructionLabel;
		private readonly string CurInstructionLabel;
		public Cgt(ILReader aReader, MethodInformation aMethodInfo)
			: base(aReader, aMethodInfo) {
			NextInstructionLabel = GetInstructionLabel(aReader.NextPosition);
			CurInstructionLabel = GetInstructionLabel(aReader);
		}
		public override void DoAssemble() {
			var xStackItem= Assembler.StackContents.Pop();
			if (xStackItem.IsFloat) {
				throw new Exception("Floats not yet supported!");
			}
			if (xStackItem.Size > 8) {
				throw new Exception("StackSizes>8 not supported");
			}
			Assembler.StackContents.Push(new StackContent(4, typeof(bool)));
			string BaseLabel = CurInstructionLabel + "__";
			string LabelTrue = BaseLabel + "True";
			string LabelFalse = BaseLabel + "False";
			if (xStackItem.Size > 4)
			{
                new CPUx86.Xor { DestinationReg = CPUx86.Registers.ESI, SourceReg = CPUx86.Registers.ESI };
				new CPUx86.Add{DestinationReg = Registers.ESI, SourceValue=1};
                new CPUx86.Xor { DestinationReg = CPUx86.Registers.EDI, SourceReg = CPUx86.Registers.EDI };
				//esi = 1
                new CPUx86.Pop { DestinationReg = CPUx86.Registers.EAX };
				new CPUx86.Pop{DestinationReg = CPUx86.Registers.EDX};
				//value2: EDX:EAX
                new CPUx86.Pop { DestinationReg = CPUx86.Registers.EBX };
                new CPUx86.Pop { DestinationReg = CPUx86.Registers.ECX };
                //value1: ECX:EBX
                new CPUx86.Sub { DestinationReg = CPUx86.Registers.EBX, SourceReg = CPUx86.Registers.EAX };
                new CPUx86.SubWithCarry { DestinationReg = CPUx86.Registers.ECX, SourceReg = CPUx86.Registers.EDX };
				//result = value1 - value2
                //new CPUx86.ConditionalMove(Condition.Greater, "edi", "esi");
                //new CPUx86.Push { DestinationReg = Registers.EDI };

                new CPUx86.JumpOnGreater { DestinationLabel = LabelTrue };
				new CPUx86.Push{DestinationValue=0};
				new CPUx86.Jump{DestinationLabel=NextInstructionLabel};
				new CPU.Label(LabelTrue);
				new CPUx86.Push{DestinationValue=1};

			} else
			{
                new CPUx86.Pop { DestinationReg = CPUx86.Registers.EAX };
                new CPUx86.Compare { DestinationReg = CPUx86.Registers.EAX, SourceReg = CPUx86.Registers.ESP, SourceIsIndirect = true };
                new CPUx86.JumpIfGreater { DestinationLabel = LabelTrue };
                new CPUx86.Jump { DestinationLabel = LabelFalse };
				new CPU.Label(LabelTrue);
                new CPUx86.Add { DestinationReg = CPUx86.Registers.ESP, SourceValue = 4 };
				new CPUx86.Push{DestinationValue=1};
                new CPUx86.Jump { DestinationLabel = NextInstructionLabel };
				new CPU.Label(LabelFalse);
				new CPUx86.Add{DestinationReg = CPUx86.Registers.ESP, SourceValue=4};
                new CPUx86.Push { DestinationValue = 0 };
                new CPUx86.Jump { DestinationLabel = NextInstructionLabel };
			}
		}
	}
}