public override void BranchIf(bool sense, Label target)
{
var f=FuncBuilder.Instance;
var emitter=CodeGenerator.Emitter;
var declarer=f.Declare;
using(f.OpenScope("compare")) {
var lhsTemp=declarer.Int("lhs");
var rhsTemp=declarer.Int("rhs");
var lhsResult=lhs.EvaluateTo(lhsTemp);
var rhsResult=rhs.EvaluateTo(rhsTemp);
var lhsReg=lhsResult.ToRegister(f.Scratch0);
var rhsRegOrByte=rhsResult.ToRegisterOrByte(f.Scratch1);
if(rhsRegOrByte.IsRegister) {
emitter.Emit(Format4OpCode.CMP, lhsReg, rhsRegOrByte.Register);
} else {
emitter.Emit(Format3OpCode.CMP, lhsReg, rhsRegOrByte.Byte);
}
var instructionToUse=sense ? branchOpCode : inverseOpCode;
var address=target.GetLabelAddressBestEffort();
emitter.Emit(instructionToUse, address);
}
}
public Static(int declarationIndex, Label storageLabel, int[] initialData)
{
this.DeclarationIndex=declarationIndex;
if(initialData.Length==1 && initialData[0]==0) {
initialData=OneZero;
}
this.StorageLabel=storageLabel;
this.InitialData=initialData;
}
public override void BranchIf(bool sense, Label target)
{
if(!sense) {
//if you want lhs||rhs to be false, then you will succeed if lhs is false and rhs is false
Invert().BranchIf(true, target);
} else {
//if you want lhs||rhs to be true, then you will succeed if lhs is true or rhs is true
lhs.BranchIf(true, target);
rhs.BranchIf(true, target);
}
}
public static void UnconditionalBranchTo(Label target)
{
var emitter=CodeGenerator.Emitter;
var targetAddress=target.GetLabelAddressBestEffort();
var caddr=emitter.CurrentAddress;
//branch to next instruction or branch to self cause this instruction to be elided
//why: in phase N, a needless branch will look like a branch to the next instruction,
// but in phase N+1 it will look like a branch to self
if(targetAddress==caddr || targetAddress==caddr+2) {
Debug.Print("<branch to next instruction removed>");
} else {
emitter.Emit(Format18OpCode.B, targetAddress);
}
}
public override void BranchIf(bool sense, Label target)
{
var f=FuncBuilder.Instance;
if(!sense) {
//if you want lhs&&rhs to be false, then you will succeed if lhs is false or rhs is false
lhs.BranchIf(false, target);
rhs.BranchIf(false, target);
} else {
//but if you want lhs&&rhs to be true, then you will succeed if lhs is true and rhs is true
var fail=f.DeclareLabel("fail");
lhs.BranchIf(false, fail);
rhs.BranchIf(true, target);
fail.Mark();
}
}
public abstract void BranchIf(bool sense, Label target);
public AddressOf(Label label, bool wantThumbAdjustment)
{
this.label=label;
this.wantThumbAdjustment=wantThumbAdjustment;
}
public FuncDeclaration(string name)
{
this.Name=name;
this.EntryPoint=CodeGenerator.Instance.DeclareStaticLabel(name);
}
public void BindStaticVariableToNewRepresentation(IReference variable, string name, int[] initialData)
{
var terminalName=CreateTerminalName(name);
var label=new Label(terminalName);
var representation=new Static(staticVariableToInfo.Count, label, initialData);
staticVariableToInfo.CheckedAdd(variable, new StaticVariableInfo(terminalName, representation));
}
private FuncBuilder(Namespace ns, FuncBuilderHints builderHints, ActionOnFuncBuilder action)
{
Instance=this;
this.namespaceAndNextIndex=new NamespaceAndNextIndex(ns, 0);
this.BuilderHints=builderHints;
var pt=builderHints.PassTraits;
this.Scratch0=pt.Scratch0;
this.Scratch1=pt.Scratch1;
var emitter=CodeGenerator.Emitter;
var passTraits=BuilderHints.PassTraits;
var preserveLr=passTraits.PreserveLinkRegister;
var regsToPreserve=passTraits.RegisterMask&0xf0;
emitter.EmitIfNecessary(Format14OpCode.PUSH, preserveLr, (byte)regsToPreserve);
if(preserveLr) {
StackPointer+=-4;
}
while(regsToPreserve!=0) {
StackPointer+=-4;
regsToPreserve&=(regsToPreserve-1);
}
this.EndOfVariableRegion=StackPointer;
var avo=passTraits.AllocatedVariableOffset;
emitter.EmitIfNecessary(Format13OpCode.ADDSP, avo);
StackPointer+=avo;
this.TheExitLabel=DeclareLabel("leave");
action(this);
TheExitLabel.Mark();
StackPointer+=-avo;
emitter.EmitIfNecessary(Format13OpCode.ADDSP, -avo);
regsToPreserve=passTraits.RegisterMask&0xf0;
emitter.EmitIfNecessary(Format14OpCode.POP, false, (byte)regsToPreserve);
Register bxRegister;
if(passTraits.PreserveLinkRegister) {
bxRegister=new LowRegister(1);
emitter.EmitIfNecessary(Format14OpCode.POP, false, 1<<1);
} else {
bxRegister=Register.LR;
}
emitter.Emit(Format5OpCode.BX, null, bxRegister);
if(inflightUtterances.Count>0) {
var allUtterances="";
foreach(string utterance in inflightUtterances.Values) {
if(allUtterances.Length>0) {
allUtterances+=",";
}
allUtterances+=utterance;
}
throw new Exception(allUtterances);
}
}