private void addAlternateEquate() throws InvalidInputException, DuplicateNameException {
		EquateTable equateTable = program.getEquateTable();
		Equate equate = equateTable.getEquate(altName);

		if (equate != null && equate.getValue() != altValue) {
			String msg = "Equate named " + altName + " already exists with value of " +
				equate.getValue() + ".";
			throw new DuplicateNameException(msg);
		}

		if (equate == null) {
			equate = equateTable.createEquate(altName, altValue);
		}

		equate.addReference(altAddress, altIndex);
	}
Add equate based on the direct constant information: convertAddress, convertName, convertHash
@throws DuplicateNameException if there is already an equate with same name but different value
@throws InvalidInputException if the equate name is illegal
Ghidra/Features/Decompiler/src/main/java/ghidra/app/plugin/core/decompile/actions/ConvertConstantTask.java