@Override
	public MaskedLong computeLeft(MaskedLong rval, MaskedLong goal) throws SolverException {
		return rval.add(goal);
	}
Solves expressions of the form {@code A - B}
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/assembler/sleigh/expr/SubExpressionSolver.java