Figure 12.17 typo

[zhuozhiyongde]

https://hansimov.gitbook.io/csapp/part3/ch12-concurrent-programming/12.5-synchronizing-thread-with-semaphores

配图有误（原书笔误）

Ref: https://stackoverflow.com/questions/48304514/what-does-this-x86-64-addq-instruction-mean-which-only-have-one-operand-from#comment83594042_48304514

[dst111dst]

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[zhuozhiyongde]

根据官方改错 似乎应该是改后面两句

https://csapp.cs.cmu.edu/3e/errata.html

p. 997, The text describing Figure 12.17 is correct, but the Figure itself has two typos: The Ui instruction should be addq $1, %rdx. The Si instruction should be movq %rdx, cnt(%rip). Posted 02/22/2018. Dr. Joann J Ordille

[Hansimov]

@zhuozhiyongde 多谢补充和考证，有心了！我把这个 issue pin 起来。