MMU_MASK 和 rlwinm

#define MMU_MASK(src, des)      rlwinm  des, src, 0, 28, 25


rlwinm EREF_RM.pdf

rlwinm  des, src, 0, 28, 25
===
rlwinm  rA,rS,SH,MB,ME   (Rc=0)
rlwinm. rA,rS,SH,MB,ME   (Rc=1)


n ← SH
b ← MB+32
e ← ME+32
r ← ROTL 32 ((rS) 32:63 ,n)
k ← MASK(b,e)
result ← r & k
if Rc=1 then do
LT ← result m:63 < 0
GT ← result m:63 > 0
EQ ← result m:63 = 0
CR0 ← LT || GT || EQ || SO
rA ← result
===
pem32b.cdf

Mask[28,25] =
IF( 28<=25)
  mask[mstart:mstop] = ones
  mask[all other bits] = zeros
ELSE
  MASK[28,31]=1
  MASK[0,25] =1
  OTHERS =0
  0b 1111 1111 1111 1111 1111 1111 1100 1111 = 0xffffffcf.

IS DS are cleared.