L2 Instruction Cache
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
11-9
The L2 ICache fetches code from a higher hierarchy memory and enables the cores (in case of a
miss in their L1 ICache) to fetch a code from level 2 cache memory with reasonable degradation,
instead of the high miss penalty to access higher hierarchy memory directly. Cacheable accesses
activate the cache, and in case of a hit, return the data to the DSP core subsystem. In case of a
miss, the instruction cache issues fetch requests to the higher-level memory, and can prefetch
more data than requested (limited by the end of the cache line) to reduce the performance impact
due to subsequent accesses.
The L2 ICache includes the following:
2
×
64 KB interleaved cache bank memories (total of 128 KB) with an interleave
resolution of 256 bytes (line size).
8 way associative cache.
32 cache indexes (5 bits) in each bank.
128-bit valid bit resolution (VBR).
256-byte cache line size (16 VBRs).
8
×
32 = 256 cache lines (TAGs) per bank.
L2 ICache initiator and target buses are 128 bits wide. The L2 ICache connects to four
initiators (the 4 cores) and one target (the internal MBus).
Supports both cacheable and non-cacheable accesses determined by a user configured
address range.
Supports wrap transactions.
Supports big-endian data.
Cache contains dedicated registers for programming and debug through the MBus.
Supports cache sweep operations for coherency support, that is, you can invalidate cache
lines within a specified address range.
Hits are identified in pre-fetched data (pre-fetch hit).
Supports pre-fetch accesses to the end of the cache line (256 bytes).
Partial lock allows you to lock a subset of cache lines based on way boundaries.
Supports a pseudo-LRU (PLRU) cache line replacement algorithm.
Provides dedicated exceptions for each of the following events:
— Profiling interrupts:
•
Watch point event.
•
Overflow.
— Error detection and correction in L2 ICache memory (single-bit detection and
correction with no assurance for multi-bit detection.
Automatic built-in-self-test (ABIST) of the ICache memory.
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...