private static int getDefaultStackDepthChange(Program depthProgram, int depth) {
		PrototypeModel defaultModel = depthProgram.getCompilerSpec().getDefaultCallingConvention();
		int callStackMod = defaultModel.getExtrapop();
		int callStackShift = defaultModel.getStackshift();
		if (callStackMod != PrototypeModel.UNKNOWN_EXTRAPOP && callStackShift >= 0) {
			return callStackShift - callStackMod;
		}
		return depth;
	}
Get the default/assumed stack depth change for this language

@param depth stack depth to return if the default is unknown for the language
@return
Ghidra/Features/Base/src/main/java/ghidra/util/state/ResultsState.java