Cosmos/source/Compiler/Indy.IL2CPU.X86/IL/x86/Bge.cs

using System;
using System.IO;


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

namespace Indy.IL2CPU.IL.X86 {
	[OpCode(OpCodeEnum.Bge)]
	public class Bge: Op {
		public readonly string TargetLabel;
		public readonly string CurInstructionLabel;
        private string mNextLabel;
	    private string mCurLabel;
	    private uint mCurOffset;
	    private MethodInformation mMethodInformation;
		public Bge(ILReader aReader, MethodInformation aMethodInfo)
			: base(aReader, aMethodInfo) {
			TargetLabel = GetInstructionLabel(aReader.OperandValueBranchPosition);
			CurInstructionLabel = GetInstructionLabel(aReader);
             mMethodInformation = aMethodInfo;
		    mCurOffset = aReader.Position;
		    mCurLabel = IL.Op.GetInstructionLabel(aReader);
            mNextLabel = IL.Op.GetInstructionLabel(aReader.NextPosition);
		}

		private void DoAssemble32Bit() {
			string BaseLabel = CurInstructionLabel + "__";
			string LabelTrue = BaseLabel + "True";
			string LabelFalse = BaseLabel + "False";
#warning Code checking: strange code seems to be generated. Read the following comments:
			//Jump right after JumpIfGreaterOrEquals to the same label
			//my offer is:
			new CPUx86.Pop{DestinationReg = CPUx86.Registers.EBX};
            new CPUx86.Pop { DestinationReg = CPUx86.Registers.EAX };
            new CPUx86.Compare { DestinationReg = CPUx86.Registers.EAX, SourceReg=CPUx86.Registers.EBX };
            new CPUx86.ConditionalJump { Condition = CPUx86.ConditionalTestEnum.GreaterThanOrEqualTo, DestinationLabel = LabelTrue };
            new CPUx86.Jump { DestinationLabel = LabelFalse };
			new CPU.Label(LabelTrue);
            new CPUx86.Jump { DestinationLabel = TargetLabel };
			new CPU.Label(LabelFalse);
			//new CPUx86.Pop(CPUx86.Registers_Old.EAX);
			//new CPUx86.Compare(CPUx86.Registers_Old.EAX, CPUx86.Registers_Old.AtESP);
			//new CPUx86.JumpIfGreaterOrEquals(LabelTrue);
			//new CPUx86.Jump(LabelTrue);
			//new CPU.Label(LabelTrue);
			//new CPUx86.Add(CPUx86.Registers_Old.ESP, "4");
			//new CPUx86.Jump(TargetLabel);
			//new CPU.Label(LabelFalse);
			//new CPUx86.Add(CPUx86.Registers_Old.ESP, "4");
		}

		private void DoAssemble64Bit() {
			//throw new NotImplementedException("long comprasion is not implemented");
			string BaseLabel = CurInstructionLabel + "__";
			string LabelTrue = BaseLabel + "True";
			string LabelFalse = BaseLabel + "False";
			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.ConditionalJump { Condition = CPUx86.ConditionalTestEnum.GreaterThanOrEqualTo, DestinationLabel = TargetLabel };
		}

		public override void DoAssemble() {
			StackContent xItem1 = Assembler.StackContents.Pop();
			StackContent xItem2 = Assembler.StackContents.Pop();
			int xSize = Math.Max(xItem1.Size, xItem2.Size);
			var xIsFloat = xItem1.IsFloat || xItem2.IsFloat;
			if (xIsFloat) {
                EmitNotSupportedException(Assembler, GetServiceProvider(), "Floats are not yet supported (Bge)", mCurLabel, mMethodInformation, mCurOffset, mNextLabel);
                return;
			}
			if (xSize > 8) {
                EmitNotSupportedException(Assembler, GetServiceProvider(), "StackSize>8 not supported (Bge)", mCurLabel, mMethodInformation, mCurOffset, mNextLabel);
                return;
			}
			if (xSize > 4) {
				DoAssemble64Bit();
			} else {
				DoAssemble32Bit();
			}
		}
	}
}