Stereo System User Manual

MOTOROLA 23
tors could be “least recently used” although they can not be replaced. Therefore, the “next
to be replaced sector” is the only sector whose lru bit is set and lock bit cleared. The ex-
ception to this rule is the case where all of the eight sectors are locked and designated as
“least recently used”, in which case there is no “next to be replaced sector” because no
sector will be replaced until at least one sector is unlocked.
TAG number 0
031
msb lsb 0 0
76
TAG number 1msb lsb 0 0
TAG number 2msb lsb 0 0
TAG number 3msb lsb 0 0
TAG number 4msb lsb 0 0
TAG number 5msb lsb 0 0
TAG number 6msb lsb 0 0
TAG number 7msb lsb 0 0
lock lock 0 0
001 77
lru lru lru LRU/LOCK status
31 30 29 1617 15 0
lock
1
28
Figure 4 - Circular Tags Buffer