private static IEnumerable <AssemblyLine> CreateMethods(CompiledProgram program)
{
var nodes = program.CallGraph.AllNodes;
var methods = program.Types.SelectMany(t => t.Subroutines)
.Where(s => s != program.EntryPoint)
.Where(s => s.Body.Any()) // Don't emit empty methods.
.Where(s => nodes.Any(n => n.Value == s.MethodDefinition)); // Don't emit methods that are never called.
yield return(Comment("Begin subroutine emit.", 0));
yield return(BlankLine());
foreach (var method in methods)
{
// Do not emit subroutines that will never be JSR'd.
if (method.TryGetFrameworkAttribute <AlwaysInlineAttribute>(out _))
{
continue;
}
foreach (var line in CreateMethod(method))
{
yield return(line);
}
}
yield return(Comment("End subroutine emit.", 0));
yield return(BlankLine());
IEnumerable <AssemblyLine> CreateMethod(CompiledSubroutine subroutine)
{
yield return(Comment(subroutine.MethodDefinition.ToString(), 0));
yield return(Label(LabelGenerator.GetFromMethod(subroutine.MethodDefinition)));
foreach (var line in subroutine.Body)
{
yield return(line);
}
yield return(BlankLine());
}
}
private IEnumerable <AssemblyLine> Call(Instruction instruction)
{
// Could be either a MethodDefinition or MethodReference.
MethodReference method = (MethodReference)instruction.Operand;
var methodDeclaringType = method.DeclaringType.FullName;
var processedSubroutine = Types[methodDeclaringType].Subroutines.Single(s => s.FullName == method.FullName);
// Check if this method should be replaced with a direct store to a symbol (generally a TIA register).
// Don't directly compare types since we may have received a different Framework assembly than what this library was built against.
if (processedSubroutine.TryGetFrameworkAttribute <OverrideWithStoreToSymbolAttribute>(out var overrideStore))
{
if (!overrideStore.Strobe)
{
//TODO - We assume this is a 1-arg void method. Actually enforce this at the processing stage.
if (method.Parameters.Count != 1)
{
throw new NotImplementedException($"{method.Name}, marked with {nameof(OverrideWithStoreToSymbolAttribute)}, must take 1 parameter for now.");
}
yield return(PLA());
}
yield return(STA(overrideStore.Symbol));
yield break;
}
if (processedSubroutine.TryGetFrameworkAttribute <OverrideWithLoadToRegisterAttribute>(out var overrideRegisterLoad))
{
//TODO - We assume this is a 1-arg void method. Actually enforce this at the processing stage.
if (method.Parameters.Count != 1)
{
throw new NotImplementedException($"{method.Name}, marked with {nameof(OverrideWithLoadToRegisterAttribute)} must take 1 parameter.");
}
yield return(PLA());
switch (overrideRegisterLoad.Register)
{
case "A":
break;
case "X":
yield return(TAX());
break;
case "Y":
yield return(TAY());
break;
default:
throw new FatalCompilationException($"Attempted load to unknown register: {overrideRegisterLoad.Register}");
}
yield break;
}
if (processedSubroutine.TryGetFrameworkAttribute <OverrideWithLoadFromSymbolAttribute>(out var overrideLoad))
{
if (method.Parameters.Count != 0)
{
throw new NotImplementedException($"{method.Name}, marked with {nameof(OverrideWithLoadFromSymbolAttribute)}, must take 0 parameters.");
}
yield return(LDA(overrideLoad.Symbol));
yield return(PHA());
yield break;
}
var parameters = ((MethodReference)method).Parameters.ToImmutableArray();
if (parameters.Any())
{
// PLA arguments in reverse off stack and assign to parameters.
foreach (var parameter in parameters.Reverse())
{
yield return(PLA());
yield return(STA(LabelGenerator.GetFromParameter(parameter)));
}
}
if (processedSubroutine.TryGetFrameworkAttribute <AlwaysInlineAttribute>(out _))
{
var compiledSubroutine = Types[method.DeclaringType.FullName].Subroutines.Single(s => s.FullName == method.FullName) as CompiledSubroutine;
if (compiledSubroutine == null)
{
throw new FatalCompilationException($"Attempted to inline method '{processedSubroutine.Name}' that hasn't been compiled yet. This suggests a bug in determining method compilation order.");
}
foreach (var assemblyLine in compiledSubroutine.Body)
{
//TODO - If the subroutine contains labels you can end up emitting duplicates if the inline subroutine is called more than once. Make them unique.
//TODO - Once we have branching and multiple return statements this will explode.
// In reality we probably want to replace RTS with JMP to a label inserted after this method body.
if (!assemblyLine.Text.Contains("RTS"))
{
yield return(assemblyLine);
}
}
yield break;
}
yield return(JSR(LabelGenerator.GetFromMethod(method)));
}