VS2019 could not evaluate ebp-n
 

I'm debugging Bochs's source code in recent days,
sometimes I need to switch to disassembly code(Ctrl+Alt+D)
and open Debug->Windows->Memory to watch
the variables accessed in the instructions.
To my surprise, VC2019 seems unable to evaluate the
variables located in the stack, for example, ebp, ebp+8
or ebp-4 are all denied in the memory window, and
even I enter the value of ebp in the memory, VC2019
still does not show anything.

Is there anybody who has an idea of this issue?

https://blog.cnstock.com/UploadFiles...1530211082.jpg