public Register getRegister(Address addr, int size) {
		AddressSpace space = addr.getAddressSpace();
		if (space.isRegisterSpace() || space.hasMappedRegisters()) {
			return sizeMap.get(new RegisterSizeKey(addr, size));
		}
		return null;
	}
Get register by address and size

@param addr register address
@param size register size
@return register or null if not found
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/lang/RegisterManager.java