Ryujinx/Ryujinx.HLE/HOS/Tamper/CodeEmitters/EndConditionalBlock.cs

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using Ryujinx.HLE.Exceptions;
using Ryujinx.HLE.HOS.Tamper.Conditions;
using Ryujinx.HLE.HOS.Tamper.Operations;
using System.Collections.Generic;
namespace Ryujinx.HLE.HOS.Tamper.CodeEmitters
{
/// <summary>
/// Code type 2 marks the end of a conditional block (started by Code Type 1, Code Type 8 or Code Type C0).
/// </summary>
class EndConditionalBlock
{
const int TerminationTypeIndex = 1;
private const byte End = 0; // True end of the conditional.
private const byte Else = 1; // End of the 'then' block and beginning of 'else' block.
public static void Emit(byte[] instruction, CompilationContext context)
{
Emit(instruction, context, null);
}
private static void Emit(byte[] instruction, CompilationContext context, IEnumerable<IOperation> operationsElse)
{
// 2X000000
// X: End type (0 = End, 1 = Else).
byte terminationType = instruction[TerminationTypeIndex];
switch (terminationType)
{
case End:
break;
case Else:
// Start a new operation block with the 'else' instruction to signal that there is the 'then' block just above it.
context.BlockStack.Push(new OperationBlock(instruction));
return;
default:
throw new TamperCompilationException($"Unknown conditional termination type {terminationType}");
}
// Use the conditional begin instruction stored in the stack.
var upperInstruction = context.CurrentBlock.BaseInstruction;
CodeType codeType = InstructionHelper.GetCodeType(upperInstruction);
// Pop the current block of operations from the stack so control instructions
// for the conditional can be emitted in the upper block.
IEnumerable<IOperation> operations = context.CurrentOperations;
context.BlockStack.Pop();
// If the else operations are already set, then the upper block must not be another end.
if (operationsElse != null && codeType == CodeType.EndConditionalBlock)
{
throw new TamperCompilationException($"Expected an upper 'if' conditional instead of 'end conditional'");
}
ICondition condition;
switch (codeType)
{
case CodeType.BeginMemoryConditionalBlock:
condition = MemoryConditional.Emit(upperInstruction, context);
break;
case CodeType.BeginKeypressConditionalBlock:
condition = KeyPressConditional.Emit(upperInstruction, context);
break;
case CodeType.BeginRegisterConditionalBlock:
condition = RegisterConditional.Emit(upperInstruction, context);
break;
case CodeType.EndConditionalBlock:
terminationType = upperInstruction[TerminationTypeIndex];
// If there is an end instruction above then it must be an else.
if (terminationType != Else)
{
throw new TamperCompilationException($"Expected an upper 'else' conditional instead of {terminationType}");
}
// Re-run the Emit with the else operations set.
Emit(instruction, context, operations);
return;
default:
throw new TamperCompilationException($"Conditional end does not match code type {codeType} in Atmosphere cheat");
}
// Create a conditional block with the current operations and nest it in the upper
// block of the stack.
IfBlock block = new IfBlock(condition, operations, operationsElse);
context.CurrentOperations.Add(block);
}
}
}