Re-order buffer: branches

When the ROB encounters a conditional branch, there are two cases:

• Correctly-predicted

  No further action is necessary

• Incorrectly-predicted

  Need to prevent updates which would arise from mis-speculatively-executed inst$^{\rm n}$s still to be committed

  Action:

  • Flush entire ROB contents

    (so still-finishing inst$^{\rm n}$s broadcast results but results aren't collected)

  • Fetch next inst$^{\rm n}$ from proper next PC address