public int getRegDepth(Address addr, Register reg) {
		Value rValue = symEval.getRegisterValue(addr, reg);
		if (rValue == null) {
			return Function.INVALID_STACK_DEPTH_CHANGE;
		}
		Register relativeReg = rValue.getRelativeRegister();
		if (!reg.equals(stackReg)) {
			if (relativeReg == null || !relativeReg.equals(stackReg)) {
				return Function.INVALID_STACK_DEPTH_CHANGE;
			}
		}
		else if (relativeReg != null && !relativeReg.equals(stackReg)) {
			return Function.INVALID_STACK_DEPTH_CHANGE;
		}
		return (int) rValue.getValue();
	}
Get the stack register depth at address.
 To have a valid value, the class must be constructed to storeDepthAtEachInstuction
 
@param addr the address to get the register depth at.
@param reg the register to get the depth of.
@return the depth of the register at the address.
Ghidra/Features/Base/src/main/java/ghidra/app/cmd/function/CallDepthChangeInfo.java