请教关于branch target buffer的问题

[librangel]

Branch Target Buffer (BTB) reduces the penalty by predicting the path of the branch, computing
the target of branch and caching the information used by the branch. There will be no
stalls if the branch entry found on BTB and the prediction is correct, otherwise the penalty
will be at least two cycles.

请问这个target指什么？是哪个brach要用到的信息吗？
如果预测错了 这个branch target buffer 怎么较少penalty了？没看明白 预测错了不是还要discard所预测错的内容嘛？
请高人指点
谢谢

[evanxgsh]

不懂帮顶