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