Section 8 Caches
Rev.1.00 Dec. 13, 2005 Page 210 of 1286
REJ09B0158-0100
5. Cache miss (copy-back, no write-back)
A data write in accordance with the access size is performed for the data of the data field on
the hit way which is indexed by virtual address bits [4:0]. Then, the data, excluding the cache-
missed data which is written already, is read into the cache line on the way which is selected to
replace from the physical address space corresponding to the virtual address.
Data reading is performed, using the wraparound method, in order from the quad-word data (8
bytes) including the cache-missed data. While the remaining data on the cache line is being
read, the CPU can execute the next processing. When reading of one line of data is completed,
the tag corresponding to the physical address is recorded in the cache, 1 is written to the V bit
and the U bit on the way. Then the LRU bit is updated to indicate the way is latest one.
6. Cache miss (copy-back, with write-back)
The tag and data field of the cache line on the way which is selected to replace are saved in the
write-back buffer. Then a data write in accordance with the access size is performed for the
data field on the hit way which is indexed by virtual address bits [4:0]. Then, the data,
excluding the cache-missed data which is written already, is read into the cache line on the
way which is selected to replace from the physical address space corresponding to the virtual
address. Data reading is performed, using the wraparound method, in order from the quad-
word data (8 bytes) including the cache-missed data. While the remaining data on the cache
line is being read, the CPU can execute the next processing. When reading of one line of data
is completed, the tag corresponding to the physical address is recorded in the cache, 1 is
written to the V bit and the U bit on the way. Then the LRU bit is updated to indicate the way
is latest one. Then the data in the write-back buffer is then written back to external memory.
7. Cache miss (write-through)
A write of the specified access size is performed to the external memory corresponding to the
virtual address. In this case, a write to cache is not performed.
Содержание SH7780 Series
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Страница 292: ...Section 9 L Memory Rev 1 00 Dec 13 2005 Page 242 of 1286 REJ09B0158 0100 ...
Страница 450: ...Section 11 Local Bus State Controller LBSC Rev 1 00 Dec 13 2005 Page 400 of 1286 REJ09B0158 0100 ...
Страница 492: ...Section 12 DDR SDRAM Interface DDRIF Rev 1 00 Dec 13 2005 Page 442 of 1286 REJ09B0158 0100 ...
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Страница 692: ...Section 16 Watchdog Timer and Reset Rev 1 00 Dec 13 2005 Page 642 of 1286 REJ09B0158 0100 ...
Страница 726: ...Section 18 Timer Unit TMU Rev 1 00 Dec 13 2005 Page 676 of 1286 REJ09B0158 0100 ...
Страница 1004: ...Section 24 Multimedia Card Interface MMCIF Rev 1 00 Dec 13 2005 Page 954 of 1286 REJ09B0158 0100 ...
Страница 1032: ...Section 25 Audio Codec Interface HAC Rev 1 00 Dec 13 2005 Page 982 of 1286 REJ09B0158 0100 ...
Страница 1070: ...Section 26 Serial Sound Interface SSI Module Rev 1 00 Dec 13 2005 Page 1020 of 1286 REJ09B0158 0100 ...
Страница 1104: ...Section 27 NAND Flash Memory Controller FLCTL Rev 1 00 Dec 13 2005 Page 1054 of 1286 REJ09B0158 0100 ...
Страница 1150: ...Section 28 General Purpose I O GPIO Rev 1 00 Dec 13 2005 Page 1100 of 1286 REJ09B0158 0100 ...
Страница 1184: ...Section 29 User Break Controller UBC Rev 1 00 Dec 13 2005 Page 1134 of 1286 REJ09B0158 0100 ...
Страница 1266: ...Section 31 Electrical Characteristics Rev 1 00 Dec 13 2005 Page 1216 of 1286 REJ09B0158 0100 ...
Страница 1328: ...Appendix Rev 1 00 Dec 13 2005 Page 1278 of 1286 REJ09B0158 0100 ...
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