HD6417751RBP240V Datasheet, PDF (213/1226 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

H'7C00 4000 to H'7C00 5FFF (8 KB): Corresponds to RAM area 1
H'7C00 6000 to H'7C00 7FFF (8 KB): Corresponds to RAM area 2
:
:
:
A shadow of the RAM area occurs every 16 Kbytes up to H'7FFF FFFF.
4. Caches
4.3.7 OC Index Mode
Setting CCR.OIX to 1 enables OC indexing to be performed using bit [25] of the effective
address. This is called OC index mode. In normal mode, with CCR.OIX cleared to 0, OC indexing
is performed using bits [13:5] of the effective address. Using index mode allows the OC to be
handled as two areas by means of effective address bit [25], providing efficient use of the cache.
Note that in the SH7751R, RAM mode cannot be used when OC index mode is used.
4.3.8 Coherency between Cache and External Memory
Coherency between cache and external memory should be assured by software. In this LSI, the
following four new instructions are supported for cache operations. Details of these instructions
are given in the Programming Manual.
Invalidate instruction:
Purge instruction:
Write-back instruction:
Allocate instruction:
OCBI @Rn
OCBP @Rn
OCBWB @Rn
MOVCA.L R0,@Rn
Cache invalidation (no write-back)
Cache invalidation (with write-back)
Cache write-back
Cache allocation
4.3.9 Prefetch Operation
This LSI supports a prefetch instruction to reduce the cache fill penalty incurred as the result of a
cache miss. If it is known that a cache miss will result from a read or write operation, it is possible
to fill the cache with data beforehand by means of the prefetch instruction to prevent a cache miss
due to the read or write operation, and so improve software performance. If a prefetch instruction
is executed for data already held in the cache, or if the prefetch address results in a UTLB miss or
a protection violation, the result is no operation, and an exception is not generated. Details of the
prefetch instruction are given in the Programming Manual.
Prefetch instruction:
PREF @Rn
Rev.4.00 Oct. 10, 2008 Page 113 of 1122
REJ09B0370-0400