public Expression BuildInstructionSpaceExpression(IEnumerable<InstructionInfo> instructions,
IProgramControlExpressionLibrary programControlExpressionLibrary,
IInstructionExpressionBuilder instructionBuilder,
InstructionSpace instructionSpace)
{
if (instructionSpace.Prefix == null)
return BuildSwitch(instructions, programControlExpressionLibrary, instructionBuilder, String.Empty);
else
return BuildSwitch(instructions, programControlExpressionLibrary, instructionBuilder, instructionSpace.Prefix);
}
public Expression BuildInstructionSpaceExpression(IEnumerable<InstructionInfo> instructions,
IProgramControlExpressionLibrary programControlExpressionLibrary,
IInstructionExpressionBuilder instructionBuilder,
InstructionSpace instructionSpace)
{
List<SwitchCase> switchCases = new List<SwitchCase>();
foreach (var info in instructions)
{
if (String.IsNullOrEmpty(info.Prefix))
continue;
if (info.Prefix.StartsWith(instructionSpace.Prefix))
{
switchCases.Add(
Expression.SwitchCase(instructionBuilder.BuildExpression(info),
Expression.Constant(info.Opcode))
);
}
}
return Expression.Block(
// Read index parameter.
// index - (index & 0x80) << 1 - Handles negative indexes.
Expression.Assign(programControlExpressionLibrary.ParameterByte2, programControlExpressionLibrary.ReadAndIncrementProgramCounter),
Expression.Assign(programControlExpressionLibrary.ParameterByte1,
Expression.Subtract(
programControlExpressionLibrary.ParameterByte2,
Expression.LeftShift(
Expression.And(programControlExpressionLibrary.ParameterByte2, Expression.Constant(0x80)), Expression.Constant(0x01)
)
)
),
Expression.Switch(programControlExpressionLibrary.ReadAndIncrementProgramCounter,
Expression.Assign(programControlExpressionLibrary.ParameterByte1, programControlExpressionLibrary.ParameterByte1),
switchCases.ToArray())
);
}
private SwitchExpression BuildSwitch(IEnumerable<InstructionInfo> instructions,
IProgramControlExpressionLibrary programControlExpressionLibrary,
IInstructionExpressionBuilder instructionBuilder,
String prefix)
{
List<SwitchCase> switchCases = new List<SwitchCase>();
// Build switch cases for instruction within this prefix space.
foreach (var info in instructions)
{
if ((String.IsNullOrEmpty(prefix) && String.IsNullOrEmpty(info.Prefix)) || info.Prefix == prefix)
{
try
{
switchCases.Add(
Expression.SwitchCase(
instructionBuilder.BuildExpression(info),
Expression.Constant(info.Opcode)
)
);
}
catch (Exception ex)
{
throw new ApplicationException(String.Format("There was an error trying to build the instruction expression for {0}", info.Mnemonic), ex);
}
}
}
// Build switch cases for child instruction spaces.
foreach (var prefixOpcode in FindPrefixOpcodes(prefix, instructions))
{
IInstructionSpaceBuilder instructionSpace;
if ((prefix + prefixOpcode.ToString("X")) == "DDCB" || (prefix + prefixOpcode.ToString("X")) == "FDCB")
{
instructionSpace = new CBInstructionSpaceBuilder();
}
else
{
instructionSpace = new DefaultInstructionSpaceBuilder();
}
switchCases.Add(
Expression.SwitchCase(
instructionSpace.BuildInstructionSpaceExpression(instructions,
programControlExpressionLibrary,
instructionBuilder,
new InstructionSpace(prefix + prefixOpcode.ToString("X"))),
Expression.Constant(prefixOpcode)
)
);
}
var orderedSwitchCases = switchCases.OrderBy(sc => (Int32)((ConstantExpression)(sc.TestValues.First())).Value);
return Expression.Switch(programControlExpressionLibrary.ReadAndIncrementProgramCounter,
Expression.Block(
Expression.Throw(Expression.New(_unknownInstruction, Expression.Subtract(programControlExpressionLibrary.ProgramCounterRegister, Expression.Constant(1)))),
Expression.Assign(programControlExpressionLibrary.ParameterByte1, programControlExpressionLibrary.ParameterByte1)
),
orderedSwitchCases.ToArray()
);
}