System.Xml.Xsl.IlGen.XmlILVisitor.ZeroCompare C# (CSharp) Method

        private void ZeroCompare(QilNodeType relOp, bool isBoolVal) {
            Label lblTrue;
            Debug.Assert(relOp == QilNodeType.Eq || relOp == QilNodeType.Ne);

            // Test to determine if top stack value is zero (if relOp is Eq) or is not zero (if relOp is Ne)
            switch (this.iterCurr.CurrentBranchingContext) {
                case BranchingContext.OnTrue:
                    // If relOp is Eq, jump to true label if top value is zero (Brfalse)
                    // If relOp is Ne, jump to true label if top value is non-zero (Brtrue)
                    this.helper.Emit((relOp == QilNodeType.Eq) ? OpCodes.Brfalse : OpCodes.Brtrue, this.iterCurr.LabelBranch);
                    this.iterCurr.Storage = StorageDescriptor.None();
                    break;

                case BranchingContext.OnFalse:
                    // If relOp is Eq, jump to false label if top value is non-zero (Brtrue)
                    // If relOp is Ne, jump to false label if top value is zero (Brfalse)
                    this.helper.Emit((relOp == QilNodeType.Eq) ? OpCodes.Brtrue : OpCodes.Brfalse, this.iterCurr.LabelBranch);
                    this.iterCurr.Storage = StorageDescriptor.None();
                    break;

                default:
                    Debug.Assert(this.iterCurr.CurrentBranchingContext == BranchingContext.None);

                    // Since (boolval != 0) = boolval, value on top of the stack is already correct
                    if (!isBoolVal || relOp == QilNodeType.Eq) {
                        // If relOp is Eq, push "true" if top value is zero, "false" otherwise
                        // If relOp is Ne, push "true" if top value is non-zero, "false" otherwise
                        lblTrue = this.helper.DefineLabel();
                        this.helper.Emit((relOp == QilNodeType.Eq) ? OpCodes.Brfalse : OpCodes.Brtrue, lblTrue);
                        this.helper.ConvBranchToBool(lblTrue, true);
                    }

                    this.iterCurr.Storage = StorageDescriptor.Stack(typeof(bool), false);
                    break;
            }
        }