Cosmos/source/Indy.IL2CPU/IL/x86/Clt.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.Clt)]
	public class Clt: Op {
		private readonly string NextInstructionLabel;
		private readonly string CurInstructionLabel;
		public Clt(ILReader aReader, MethodInformation aMethodInfo)
			: base(aReader, aMethodInfo) {
			NextInstructionLabel = GetInstructionLabel(aReader.NextPosition);
			CurInstructionLabel = GetInstructionLabel(aReader);
		}
		public override void DoAssemble() {
			if (Assembler.StackContents.Peek().IsFloat) {
				throw new Exception("Floats not yet supported!");
			}
			int xSize = Math.Max(Assembler.StackContents.Pop().Size, Assembler.StackContents.Pop().Size);
			if (xSize > 8) {
				throw new Exception("StackSizes>8 not supported");
			}
			Assembler.StackContents.Push(new StackContent(1, typeof(bool)));
			string BaseLabel = CurInstructionLabel + "__";
			string LabelTrue = BaseLabel + "True";
			string LabelFalse = BaseLabel + "False";
			if (xSize > 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=ConditionalTestEnum.LessThan, DestinationReg = CPUx86.Registers.EDI, SourceReg = CPUx86.Registers.ESI };
                new CPUx86.Push { DestinationReg = Registers.EDI };
			} else
			{
				new CPUx86.Pop{DestinationReg = CPUx86.Registers.ECX};
                new CPUx86.Pop { DestinationReg = CPUx86.Registers.EAX };
                new CPUx86.Push { DestinationReg = CPUx86.Registers.ECX };
                new CPUx86.Compare { DestinationReg = CPUx86.Registers.EAX, SourceReg = CPUx86.Registers.ESP, SourceIsIndirect = true };
                new CPUx86.ConditionalJump { Condition = CPUx86.ConditionalTestEnum.LessThan, 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 };
			}
		}
	}
}