Processor Programming (Continued)
There are five types of test operations that can be exe-
cuted:
times. Once the fill buffer holds a complete cache line of
data (16 bytes), a cache write operation transfers the data
from the fill buffer to the cache.
•
•
•
•
•
Flush buffer read
Fill buffer write
Cache write
Cache read
Cache flush
To read the contents of a cache line, a cache read opera-
tion transfers the data in the selected cache line to the
flush buffer. Once the flush buffer is loaded, the program-
mer accesses the contents of the flush buffer by executing
four flush buffer read operations.
These operations are described in detail in Table 3-18. To
fill a cache line with data, the fill buffer must be written four
Table 3-18. Cache Test Operations
Test Operation
Code Sequence
MOV TR5, 0h
Action Taken
Flush Buffer Read
Set DWORD = 0, control = 00 = flush buffer read.
Flush buffer (31:0) --> dest.
MOV dest,TR3
MOV TR5, 4h
Set DWORD = 1, control = 00 = flush buffer read.
Flush buffer (63:32) --> dest.
MOV dest,TR3
MOV TR5, 8h
Set DWORD = 2, control = 00 = flush buffer read.
Flush buffer (95:64) --> dest.
MOV dest,TR3
MOV TR5, Ch
Set DWORD = 3, control = 00 = flush buffer read.
Flush buffer (127:96) --> dest.
MOV dest,TR3
Fill Buffer Write
MOV TR5, 0h
Set DWORD = 0, control = 00 = fill buffer write.
Cache_data --> fill buffer (31:0).
MOV TR3, cache_data
MOV TR5, 4h
Set DWORD = 1, control = 00 = fill buffer write.
Cache_data --> fill buffer (63:32).
MOV TR3, cache_data
MOV TR5, 8h
Set DWORD = 2, control = 00 = fill buffer write.
Cache_data --> fill buffer (95:64).
MOV TR3, cache_data
MOV TR5, Ch
Set DWORD = 3, control = 00 = fill buffer write.
Cache_data --> fill buffer (127:96).
MOV TR3, cache_data
MOV TR4, cache_tag
MOV TR5, line+set+control=01
MOV TR5, line+set+control=10
MOV dest, TR4
Cache Write
Cache Read
Cache Flush
Cache_tag --> tag address, valid and dirty bits.
Fill buffer (127:0) --> cache line (127:0).
Cache line (127:0) --> flush buffer (127:0).
Cache line tag address, valid/LRU/dirty bits --> dest.
Control = 11 = cache flush, all cache valid bits = 0.
MOV TR5, 3h
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