4.57

A.

consider load/use hazard

E_icode in { IMRMOVQ, IPOPQ } && E_dstM in { d_srcA, d_srcB };

situation 4:

normal, no hazard happens

situation 1,2,3:

load/use hazard happens

if E_icode in { IMRMOVQ, IPOPQ }, then E_dstM must not be RNONE

consider situation 1 and 3, E_dstM == d_srcB, then d_srcB is not RNONE and must
be used in phase E, so load-forward can’t work. load-forward only work in situation 2!

consider all the instructions that d_srcA is not RNONE

ret and popq can’t work because d_srcA == d_srcB == %rsp, that’s not in
situation 2!!

finally, load/use only work in condition:

E_icode in { IMRMOVQ, IPOPQ } &&
(
  E_dstM == d_srcB ||
  (
    E_dstM == d_srcA && !(D_icode in { IRMMOVQ, IPUSHQ })
  )
);

B.

check file ./chapter4/code/sim/pipe/pipe-lf.hcl

only watch changes with origin pipe-lf.hcl

(cd ./chapter4/code/sim/pipe; diff -u origin-pipe-lf.hcl pipe-lf.hcl)

!INCLUDE './code/sim/pipe/pipe-lf.diff'