2004 Paper 8 Question 1
Comparative Architectures
(a) Why is accurate branch prediction so important to modern microprocessor
designs? [2 marks]
(b) Explain the operation of local history branch predictors, trade-offs made in
their design, and limitations in their performance. [6 marks]
(c) For what reasons are some branches difficult to predict? What strategies can
be employed to mitigate such potential performance problems? [4 marks]
(d) Describe a trace cache, and hence explain what advantages it might offer over
a traditional instruction cache. [4 marks]
(e) It is possible to obtain some of the benefits of a trace cache with a purely
software approach, using runtime binary re-writing techniques. How might
such a system operate? [4 marks]