private Variable[] getNegativeVariables() {
		if (variables.isEmpty()) {
			return emptyArray;
		}
		int length = variables.size();
		// find the end of the negatives
		int index = 0;
		for (index = 0; index < length; index++) {
			Variable var = variables.get(index);
			int stackOffset = var.getStackOffset();
			int start = stackOffset;
			if (start >= 0 || start > paramStart) {
				break;
			}
		}
		if (index == 0) {
			return emptyArray;
		}

		// return the variables in the order of -1 to -n
		List<Variable> vars = variables.subList(0, index);
		int size = vars.size();
		Variable[] retvars = new Variable[size];
		int pos = size - 1;
		for (int i = 0; i < size; i++, pos--) {
			retvars[pos] = vars.get(i);
		}
		return retvars;
	}
Get all the stack variables in the negative portion of the stack.
This EXCLUDES any variables defined before the parameter offset if the
parameter offset is negative.

@return an array of variables defined on the negative portion of the frame.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/oldfunction/OldStackFrameDB.java