GXLV Datasheet, PDF (61/247 Pages) National Semiconductor (TI) – Geode™ GXLV Processor Series Low Power Integrated x86 Solutions

Processor Programming (Continued)
There are five types of test operations that can be exe-
cuted:
• Flush buffer read
• Fill buffer write
• Cache write
• Cache read
• Cache flush
These operations are described in detail in Table 3-18. To
fill a cache line with data, the fill buffer must be written four
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.
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, access the
contents of the flush buffer with four flush buffer read
operations.
Test Operation
Flush Buffer Read
Fill Buffer Write
Cache Write
Cache Read
Cache Flush
Table 3-18. Cache Test Operations
Code Sequence
MOV TR5, 0h
MOV dest,TR3
MOV TR5, 4h
MOV dest,TR3
MOV TR5, 8h
MOV dest,TR3
MOV TR5, Ch
MOV dest,TR3
MOV TR5, 0h
MOV TR3, cache_data
MOV TR5, 4h
MOV TR3, cache_data
MOV TR5, 8h
MOV TR3, cache_data
MOV TR5, Ch
MOV TR3, cache_data
MOV TR4, cache_tag
MOV TR5, line+set+control=01
MOV TR5, line+set+control=10
MOV dest, TR4
MOV TR5, 3h
Action Taken
Set DWORD = 0, control = 00 = flush buffer read.
Flush buffer (31:0) --> dest.
Set DWORD = 1, control = 00 = flush buffer read.
Flush buffer (63:32) --> dest.
Set DWORD = 2, control = 00 = flush buffer read.
Flush buffer (95:64) --> dest.
Set DWORD = 3, control = 00 = flush buffer read.
Flush buffer (127:96) --> dest.
Set DWORD = 0, control = 00 = fill buffer write.
Cache_data --> fill buffer (31:0).
Set DWORD = 1, control = 00 = fill buffer write.
Cache_data --> fill buffer (63:32).
Set DWORD = 2, control = 00 = fill buffer write.
Cache_data --> fill buffer (95:64).
Set DWORD = 3, control = 00 = fill buffer write.
Cache_data --> fill buffer (127:96).
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.
Revision 1.1
61
www.national.com