
Chapter 13
Test and Debug
267
23542A/0—September 2000
AMD-K6-2E+ Embedded Processor Data Sheet
Preliminary Information
as illustrated in Figure 94. Similarly, if the L2 cache data is
written, the write data is taken from EAX.
Figure 94. L2 Data - EAX
L2 Tag Reads
If the L2
tag
is read (as opposed to reading the cache data), the
result is placed in EAX in the format as illustrated in Figure 95
on page 267. Similarly, if the L2 tag is written, the write data is
taken from EAX. When accessing the L2 tag, the Line, Octet,
and Dword fields of the EDX register are ignored.
.
Figure 95. L2 Tag Information for the AMD-K6-2E+ Processor—EAX
LRU (Least Recently Used).
For the 4-way set associative L2 cache,
each way has a 2-bit LRU field for each sector. Values for the
LRU field are 00b, 01b, 10b, and 11b, where 00b indicates that
the sector is “most recently used,” and 11b indicates that the
sector is “l(fā)east recently used” (see Figure 96 on page 268).
EAX[7:6] indicate LRU information for Way 0, EAX[5:4] for
Way 1, EAX[3:2]
for
Way 2, and EAX[1:0]
for
Way 3.
0
31
Data
C
M
D
Reserved
Description
Tag data read or written
Line1ST Line 1 state (M=11, E=10, S=01, I=00) 11-10
Line0ST Line 0 state (M=11, E=10, S=01, I=00) 9-8
LRU
Two bits of LRU for each way
0
Tag
31
14
12
10
9
7
8
11
LRU
Line0ST
Line1ST
Symbol
Tag
Bit
31-14
7-0
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