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using ARMeilleure.Decoders;
using ARMeilleure.IntermediateRepresentation;
using ARMeilleure.State;
using ARMeilleure.Translation;
using static ARMeilleure.Instructions.InstEmitHelper;
using static ARMeilleure.IntermediateRepresentation.OperandHelper;
namespace ARMeilleure.Instructions
{
static class InstEmitFlowHelper
{
public const ulong CallFlag = 1;
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 != null)
{
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)
{
context.Return(Const(immediate | CallFlag));
}
public static void EmitVirtualCall(ArmEmitterContext context, Operand target)
{
EmitVirtualCallOrJump(context, target, isJump: false);
}
public static void EmitVirtualJump(ArmEmitterContext context, Operand target)
{
EmitVirtualCallOrJump(context, target, isJump: true);
}
private static void EmitVirtualCallOrJump(ArmEmitterContext context, Operand target, bool isJump)
{
context.Return(context.BitwiseOr(target, Const(target.Type, (long)CallFlag)));
}
private static void EmitContinueOrReturnCheck(ArmEmitterContext context, Operand retVal)
{
// Note: The return value of the called method will be placed
// at the Stack, the return value is always a Int64 with the
// return address of the function. We check if the address is
// correct, if it isn't we keep returning until we reach the dispatcher.
ulong nextAddr = GetNextOpAddress(context.CurrOp);
if (context.CurrBlock.Next != null)
{
Operand lblContinue = Label();
context.BranchIfTrue(lblContinue, context.ICompareEqual(retVal, Const(nextAddr)));
context.Return(Const(nextAddr));
context.MarkLabel(lblContinue);
}
else
{
context.Return(Const(nextAddr));
}
}
private static ulong GetNextOpAddress(OpCode op)
{
return op.Address + (ulong)op.OpCodeSizeInBytes;
}
}
}
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