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using ARMeilleure.CodeGen.Linking;
using ARMeilleure.Decoders;
using ARMeilleure.IntermediateRepresentation;
using ARMeilleure.State;
using ARMeilleure.Translation;
using ARMeilleure.Translation.PTC;
using static ARMeilleure.Instructions.InstEmitHelper;
using static ARMeilleure.IntermediateRepresentation.Operand.Factory;
namespace ARMeilleure.Instructions
{
static class InstEmitFlowHelper
{
public static void EmitCondBranch(ArmEmitterContext context, Operand target, Condition cond)
{
if (cond != Condition.Al)
{
context.BranchIfTrue(target, GetCondTrue(context, cond));
}
else
{
context.Branch(target);
}
}
public static Operand GetCondTrue(ArmEmitterContext context, Condition condition)
{
Operand cmpResult = context.TryGetComparisonResult(condition);
if (cmpResult != default)
{
return cmpResult;
}
Operand value = Const(1);
Operand Inverse(Operand val)
{
return context.BitwiseExclusiveOr(val, Const(1));
}
switch (condition)
{
case Condition.Eq:
value = GetFlag(PState.ZFlag);
break;
case Condition.Ne:
value = Inverse(GetFlag(PState.ZFlag));
break;
case Condition.GeUn:
value = GetFlag(PState.CFlag);
break;
case Condition.LtUn:
value = Inverse(GetFlag(PState.CFlag));
break;
case Condition.Mi:
value = GetFlag(PState.NFlag);
break;
case Condition.Pl:
value = Inverse(GetFlag(PState.NFlag));
break;
case Condition.Vs:
value = GetFlag(PState.VFlag);
break;
case Condition.Vc:
value = Inverse(GetFlag(PState.VFlag));
break;
case Condition.GtUn:
{
Operand c = GetFlag(PState.CFlag);
Operand z = GetFlag(PState.ZFlag);
value = context.BitwiseAnd(c, Inverse(z));
break;
}
case Condition.LeUn:
{
Operand c = GetFlag(PState.CFlag);
Operand z = GetFlag(PState.ZFlag);
value = context.BitwiseOr(Inverse(c), z);
break;
}
case Condition.Ge:
{
Operand n = GetFlag(PState.NFlag);
Operand v = GetFlag(PState.VFlag);
value = context.ICompareEqual(n, v);
break;
}
case Condition.Lt:
{
Operand n = GetFlag(PState.NFlag);
Operand v = GetFlag(PState.VFlag);
value = context.ICompareNotEqual(n, v);
break;
}
case Condition.Gt:
{
Operand n = GetFlag(PState.NFlag);
Operand z = GetFlag(PState.ZFlag);
Operand v = GetFlag(PState.VFlag);
value = context.BitwiseAnd(Inverse(z), context.ICompareEqual(n, v));
break;
}
case Condition.Le:
{
Operand n = GetFlag(PState.NFlag);
Operand z = GetFlag(PState.ZFlag);
Operand v = GetFlag(PState.VFlag);
value = context.BitwiseOr(z, context.ICompareNotEqual(n, v));
break;
}
}
return value;
}
public static void EmitCall(ArmEmitterContext context, ulong immediate)
{
bool isRecursive = immediate == context.EntryAddress;
if (isRecursive)
{
context.Branch(context.GetLabel(immediate));
}
else
{
EmitTableBranch(context, Const(immediate), isJump: false);
}
}
public static void EmitVirtualCall(ArmEmitterContext context, Operand target)
{
EmitTableBranch(context, target, isJump: false);
}
public static void EmitVirtualJump(ArmEmitterContext context, Operand target, bool isReturn)
{
if (isReturn)
{
if (target.Type == OperandType.I32)
{
target = context.ZeroExtend32(OperandType.I64, target);
}
context.Return(target);
}
else
{
EmitTableBranch(context, target, isJump: true);
}
}
private static void EmitTableBranch(ArmEmitterContext context, Operand guestAddress, bool isJump)
{
context.StoreToContext();
if (guestAddress.Type == OperandType.I32)
{
guestAddress = context.ZeroExtend32(OperandType.I64, guestAddress);
}
// Store the target guest address into the native context. The stubs uses this address to dispatch into the
// next translation.
Operand nativeContext = context.LoadArgument(OperandType.I64, 0);
Operand dispAddressAddr = context.Add(nativeContext, Const((ulong)NativeContext.GetDispatchAddressOffset()));
context.Store(dispAddressAddr, guestAddress);
Operand hostAddress;
// If address is mapped onto the function table, we can skip the table walk. Otherwise we fallback
// onto the dispatch stub.
if (guestAddress.Kind == OperandKind.Constant && context.FunctionTable.IsValid(guestAddress.Value))
{
Operand hostAddressAddr = !context.HasPtc ?
Const(ref context.FunctionTable.GetValue(guestAddress.Value)) :
Const(ref context.FunctionTable.GetValue(guestAddress.Value), new Symbol(SymbolType.FunctionTable, guestAddress.Value));
hostAddress = context.Load(OperandType.I64, hostAddressAddr);
}
else
{
hostAddress = !context.HasPtc ?
Const((long)context.Stubs.DispatchStub) :
Const((long)context.Stubs.DispatchStub, Ptc.DispatchStubSymbol);
}
if (isJump)
{
context.Tailcall(hostAddress, nativeContext);
}
else
{
OpCode op = context.CurrOp;
Operand returnAddress = context.Call(hostAddress, OperandType.I64, nativeContext);
context.LoadFromContext();
// Note: The return value of a translated function is always an Int64 with the address execution has
// returned to. We expect this address to be immediately after the current instruction, if it isn't we
// keep returning until we reach the dispatcher.
Operand nextAddr = Const((long)op.Address + op.OpCodeSizeInBytes);
// Try to continue within this block.
// If the return address isn't to our next instruction, we need to return so the JIT can figure out
// what to do.
Operand lblContinue = context.GetLabel(nextAddr.Value);
context.BranchIf(lblContinue, returnAddress, nextAddr, Comparison.Equal, BasicBlockFrequency.Cold);
context.Return(returnAddress);
}
}
}
}
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