SH7760 Datasheet, PDF (163/1345 Pages) Renesas Technology Corp – SuperHTM RISC engine

Bit
Bit Name
31 to 26 LRUI
25, 24 
23 to 18 URB
17, 16 
Initial Value R/W
All 0
R/W
All 0
R
All 0
R/W
All 0
R
Description
Least Recently Used ITLB
These bits indicate the ITLB entry to be replaced.
The LRU (least recently used) method is used to
decide the ITLB entry to be replaced in the event
of an ITLB miss. The entry to be purged from the
ITLB can be confirmed using the LRUI bits.
LRUI is updated by means of the algorithm
shown below. x means that updating is not
performed.
000xxx: ITLB entry 0 is used
1xx00x: ITLB entry 1 is used
x1x1x0: ITLB entry 2 is used
xx1x11: ITLB entry 3 is used
xxxxxx: Other than above
When the LRUI bit settings are as shown below,
the corresponding ITLB entry is updated by an
ITLB miss. Ensure that values for which "Setting
prohibited" is indicated below are not set at the
discretion of software. After a power-on or
manual reset, the LRUI bits are initialized to 0,
and therefore a prohibited setting is never made
by a hardware update.
x means "don't care".
111xxx: ITLB entry 0 is updated
0xx11x: ITLB entry 1 is updated
x0x0x1: ITLB entry 2 is updated
xx0x00: ITLB entry 3 is updated
Other than above: Setting prohibited
Reserved
These bits are always read as 0. The write value
should always be 0.
UTLB Replace Boundary
These bits indicate the UTLB entry boundary at
which replacement is to be performed. Valid only
when URB > 0.
Reserved
These bits are always read as 0. The write value
should always be 0.
Rev. 1.0, 02/03, page 113 of 1294