Branches in a dynamic superscalar

• We want to issue a package of dependent inst s, e.g.

  

• Suppose branch is last item of prev issue (eg 1.25ex..1.25ex. we block issue of rest of package)
• Issue 2 mustn't proceed speculatively
• Because it will update several registers
• These registers are used to pass values from inst to inst
• They would have to be reinstated if the branch were mispredicted