
CHAPTER 3 CP0 REGISTERS
User’s Manual U14272EJ3V0UM
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3.2.3 EntryLo0 (2) and EntryLo1 (3) registers
The EntryLo register consists of two registers that have identical formats: EntryLo0, used for even virtual pages
and EntryLo1, used for odd virtual pages. The EntryLo0 and EntryLo1 registers are both read-/write-accessible.
They are used to access the built-in TLB. When a TLB read/write operation is carried out, the EntryLo0 and EntryLo1
registers hold the contents of the low-order 32 bits of TLB entries at even and odd addresses, respectively.
The contents of these registers are undefined after a reset so that they must be initialized by software.
Figure 3-3. EntryLo0 and EntryLo1 Registers
(a) 32-bit mode
(b) 64-bit mode
31
28 27
6
5
3
2
1
0
PFN
C
D
V
G
0
EntryLo0
31
28 27
6
5
3
2
1
0
PFN
C
D
V
G
0
EntryLo1
63
28 27
6
5
3
2
1
0
PFN
C
D
V
G
0
EntryLo0
63
28 27
6
5
3
2
1
0
PFN
C
D
V
G
0
EntryLo1
PFN:
C:
D:
Page frame number; high-order bits of the physical address.
Specifies the TLB page attribute (see
Table 3-2
).
Dirty. If this bit is set to 1, the page is marked as dirty and, therefore, writable. This bit is actually
a write-protect bit that software can use to prevent alteration of data.
Valid. If this bit is set to 1, it indicates that the TLB entry is valid; otherwise, a TLB Invalid
exception (TLBL or TLBS) occurs.
Global. If this bit is set in both EntryLo0 and EntryLo1, then the processor ignores the ASID during
TLB lookup.
Reserved for future use. Write 0 in a write operation. When this field is read, 0 is read.
V:
G:
0:
The coherency attribute (C) bits are used to specify whether to use the cache in referencing a page. When the
cache is used, whether the page attribute is “cached” or “uncached” is selected by algorithm.
Table 3-2 lists the page attributes selected according to the value in the C bits.