![](http://datasheet.mmic.net.cn/230000/V4ECFUM_datasheet_15625205/V4ECFUM_246.png)
10-14
ColdFire CF4E Core User’s Manual
For More Information On This Product,
Go to: www.freescale.com
MMU Definition
10.5.3.5 MMU Status Register (MMUSR)
MMUSR, Figure 10-6, is updated on all data access faults and search TLB operations.
Table 10-7 describes MMUSR fields.
8
STLB
Search TLB. STLB always reads as zero.
0 No operation
1 The MMU searches the TLB using data in MMUAR. This operation updates the probe TLB hit bit
in the status register plus loads the AA field as described above.
7
CA
Clear all TLB entries. CA always reads as zero.
0 No operation
1 Clear all TLB entries and all hardware TLB replacement algorithm information.
6
CNL
Clear all non-locked TLB entries. Setting CNL clears all TLB entries that do not have their locked bit
set. CNL always reads as zero.
0 No operation
1 Clear all non-locked TLB entries.
5
CAS
Clear all non-locked TLB entries that match ASID. CAS is always reads as a zero.
0 No operation
1 Clear all non-locked TLB entries that match ASID register.
4
ITLB
ITLB operation. Used by TLB search and access operations that use the TLB allocation address.
0 The MMU uses the DTLB to search or update the allocation address.
1 The MMU uses the ITLB for searches and updates of the allocation address.
3
ADR
TLB address select. Indicates which address to use when accessing the TLB.
0 Use the TLB allocation address for the TLB address.
1 Use MMUAR for the TLB address.
2
R/W
TLB access read/write select. Indicates whether to do a read or a write when accessing the TLB.
0 Write
1 Read
1
ACC
MMU TLB access. This bit always reads as a zero. STLB is used for search operations.
0 No operation. ACC should be a zero to search the TLB.
1 The MMU reads or writes the TLB depending on R/W. For TLB reads, TLB tag and data results
are loaded into MMUTR and MMUDR. For TLB writes, the contents of these registers are written
to the TLB. The TLB is accessed using the TLB allocation address if ADR is zero or using
MMUAR if ADR is set.
0
UAA
Update allocation address. UAA always reads as a zero.
0 No operation
1 MMU updates the allocation address field with the MMU’s choice for the allocation address in the
ITLB or DTLB depending on the ITLB instruction operation bit.
31
6
5
4
3
2
1
0
Field
—
SPF RF
WF
—
HIT
—
Reset
—
R/W
R/W
Rc
0x0008
Figure 10-6. MMU Status Register (MMUSR)
Table 10-6. MMUOR Field Descriptions (Continued)
Bits
Name
Description
F
Freescale Semiconductor, Inc.
n
.