MSC8113 Reference Manual, Rev. 0
9-26
Freescale Semiconductor
Extended Core
A request for code that is already in the cache is termed a cache hit. When the required code is
not present in the ICache memory array (termed a cache miss), the code is fetched from the
slower memories to the SC140 core and simultaneously loaded into the ICache memory array.
The performance degradation (DSP core timing penalty) resulting from the slower access is
termed a miss penalty. Cache updates are initiated by the fetch unit in the EQBS when a cache
miss occurs. The amount of data transferred by the fetch unit is configured in the IFUR, which
defines the number of fetch sets to transfer in a block. In addition to the basic fetch operation
(called phase 1), the prefetch unit (when enabled in the IFUR) fetches sets from the next
consecutive addresses (phase 2) to the end of the cache line or until a new cache miss begins the
next fetch sequence.
Note:
Unlike a data cache, the instruction cache depends on code not changing during run
time. If it does, the cache contents should be cleared (cache flush, no coherency
support).
When a cache miss occurs, one of several events happens:
If the upper 22 bits of the address match the tag and index in a cache line, but the VALID
bit for the fetch set position is clear, code is transferred from memory to the SC140 core
and written into the cache.
Figure 9-10. Example of Code Position Distribution in ICache
Virtual Memory Space
2
32
– 1
Fast Memory
Slow Memory
Cache Lines
(Non-Cacheable)
(Cacheable)
Slow Memory
(Non-Cacheable)
Way 0
Way 1
Way 15
N
ote: The memory range shown in the figure is the maximum definable space. The minimum definable cacheable space is 64 KB.
See Section 9.4 for details on configuring cacheable memory space.
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Summary of Contents for MSC8113
Page 1: ...MSC8113 Reference Manual Tri Core 16 Bit Digital Signal Processor MSC8113RM Rev 0 May 2008 ...
Page 20: ...MSC8113 Reference Manual Rev 0 xx Freescale Semiconductor Contents ...
Page 28: ...MSC8113 Reference Manual Rev 0 xxviii Freescale Semiconductor ...
Page 56: ...MSC8113 Reference Manual Rev 0 1 28 Freescale Semiconductor MSC8113 Overview ...
Page 76: ...MSC8113 Reference Manual Rev 0 2 20 Freescale Semiconductor SC140 Core Overview ...
Page 134: ...MSC8113 Reference Manual Rev 0 4 30 Freescale Semiconductor System Interface Unit SIU ...
Page 168: ...MSC8113 Reference Manual Rev 0 6 18 Freescale Semiconductor Boot Program ...
Page 180: ...MSC8113 Reference Manual Rev 0 7 12 Freescale Semiconductor Clocks ...
Page 260: ...MSC8113 Reference Manual Rev 0 8 80 Freescale Semiconductor Memory Map ...
Page 300: ...MSC8113 Reference Manual Rev 0 9 40 Freescale Semiconductor Extended Core ...
Page 304: ...MSC8113 Reference Manual Rev 0 10 4 Freescale Semiconductor MQBus and M2 Memory ...
Page 308: ...MSC8113 Reference Manual Rev 0 11 4 Freescale Semiconductor SQBus ...
Page 590: ...MSC8113 Reference Manual Rev 0 17 46 Freescale Semiconductor Interrupt Processing ...
Page 614: ...MSC8113 Reference Manual Rev 0 18 24 Freescale Semiconductor Debugging ...
Page 622: ...MSC8113 Reference Manual Rev 0 19 8 Freescale Semiconductor Internal Peripheral Bus IPBus ...
Page 724: ...MSC8113 Reference Manual Rev 0 21 32 Freescale Semiconductor UART ...
Page 920: ...MSC8113 Reference Manual Rev 0 25 150 Freescale Semiconductor Ethernet Controller ...
Page 1171: ...MSC8113 Reference Manual Rev 0 Freescale Semiconductor C 61 EF wait_rts P 01077FFC 9F rts 71 ...
Page 1172: ...MSC8113 Reference Manual Rev 0 C 62 Freescale Semiconductor MSC8113 Boot Code ...
Page 1202: ...MSC8113 Reference Manual Rev 0 Index 30 Freescale Semiconductor Index ...