private Register getRegister(Address addr, Map<Register, Integer> regIndexMap) {
		for (Register reg : regIndexMap.keySet()) {
			if (reg.getAddress().equals(addr)) {
				return reg;
			}
		}
		return null;
	}
Search for the register which has the specified address among register
keys contained with in the regIndexMap.

@param addr register address
@param regIndexMap register index map
@return register matching register or null if not found.
Ghidra/Features/Base/src/main/java/ghidra/program/model/listing/CodeUnitFormat.java