protected RegisterValue retrieveAndCombine(TracePlatform platform, TraceThread thread,
			int frameLevel, FoundRegister found, RegisterValue value) {
		TraceMemorySpace regSpace =
			thread.getTrace().getMemoryManager().getMemoryRegisterSpace(thread, frameLevel, false);
		if (regSpace == null) {
			return new RegisterValue(found.register, BigInteger.ZERO).combineValues(value);
		}
		return regSpace.getValue(platform, getSnap(), found.register).combineValues(value);
	}
When checking for register validity, we consider it valid if it or any of its parents are
valid, or any alias thereof.
Ghidra/Debug/Debugger-rmi-trace/src/main/java/ghidra/app/plugin/core/debug/service/tracermi/TraceRmiTarget.java