I know the meaning of Ret n but I can't figure out its role to maintaining program's runtime stack? I'm kind of confuse there. Do ret have somethig to do with stack?
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Have you read the documentation? See [here](https://c9x.me/x86/html/file_module_x86_id_280.html). You are only interested in the pseudo-code for “near return.” – fuz Dec 19 '18 at 12:43
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yes , I was able to read it – user10416143 Dec 21 '18 at 01:39
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ret n is like ret + add esp, n. You use it for caller-pops calling conventions.
Plain ret is like pop eip. (pop eip isn't a valid instruction, but it nicely expresses what ret does). Yes it uses the stack; read the documentation. http://felixcloutier.com/x86/RET.html (specifically the "near return" part.)
"far ret" is more complicated, but not used in 32 or 64-bit code with a flat memory model. i.e. not used at all in normal code.
Peter Cordes
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