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using Ryujinx.HLE.HOS.Tamper.Conditions;
namespace Ryujinx.HLE.HOS.Tamper.CodeEmitters
{
/// <summary>
/// Code type 1 performs a comparison of the contents of memory to a static value.
/// If the condition is not met, all instructions until the appropriate conditional block terminator
/// are skipped.
/// </summary>
class MemoryConditional
{
private const int OperationWidthIndex = 1;
private const int MemoryRegionIndex = 2;
private const int ComparisonTypeIndex = 3;
private const int OffsetImmediateIndex = 6;
private const int ValueImmediateIndex = 16;
private const int OffsetImmediateSize = 10;
private const int ValueImmediateSize4 = 8;
private const int ValueImmediateSize8 = 16;
public static ICondition Emit(byte[] instruction, CompilationContext context)
{
// 1TMC00AA AAAAAAAA VVVVVVVV (VVVVVVVV)
// T: Width of memory write (1, 2, 4, or 8 bytes).
// M: Memory region to write to (0 = Main NSO, 1 = Heap).
// C: Condition to use, see below.
// A: Immediate offset to use from memory region base.
// V: Value to compare to.
byte operationWidth = instruction[OperationWidthIndex];
MemoryRegion memoryRegion = (MemoryRegion)instruction[MemoryRegionIndex];
Comparison comparison = (Comparison)instruction[ComparisonTypeIndex];
ulong address = InstructionHelper.GetImmediate(instruction, OffsetImmediateIndex, OffsetImmediateSize);
Pointer sourceMemory = MemoryHelper.EmitPointer(memoryRegion, address, context);
int valueSize = operationWidth <= 4 ? ValueImmediateSize4 : ValueImmediateSize8;
ulong value = InstructionHelper.GetImmediate(instruction, ValueImmediateIndex, valueSize);
Value<ulong> compareToValue = new(value);
return InstructionHelper.CreateCondition(comparison, operationWidth, sourceMemory, compareToValue);
}
}
}
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