參數(shù)資料
型號: RM5231-150-Q
廠商: PMC-SIERRA INC
元件分類: 微控制器/微處理器
英文描述: RM5231⑩ Microprocessor with 32-Bit System Bus Data Sheet Released
中文描述: 64-BIT, 150 MHz, MICROPROCESSOR, PQFP128
封裝: POWER, QFP-128
文件頁數(shù): 19/39頁
文件大小: 630K
代理商: RM5231-150-Q
Proprietary and Confidential to PMC-Sierra, Inc and for its Customer
s Internal Use
Document ID: PMC-2002165, Issue 1
19
RM5231
Microprocessor with 32-bit System Bus Data Sheet
Released
simultaneously. The cache tag contains a 24-bit physical address, a valid bit, and has a single
parity bit.
The instruction cache is 64-bits wide and can be accessed each processor cycle. Accessing 64 bits
per cycle allows the instruction cache to supply two instructions per cycle to the superscalar
dispatch unit. For typical code sequences where a floating-point load or store and a floating-point
computation instruction are being issued together in a loop, the entire bandwidth available from
the instruction cache will be consumed.
Cache miss refill writes 64 bits per cycle to minimize the cache miss penalty. The line size is eight
instructions (32 bytes) to maximize the performance of communication between the processor and
the memory system.
The RM5231 supports instruction cache locking. The contents of one set of the cache, set A, can
be locked
by setting a bit in the coprocessor 0 Status register. Locking the set prevents its contents
from being overwritten by a subsequent cache miss. Refill will occur only into set B. This
mechanism allows the programmer to lock critical code into the cache thereby guaranteeing
deterministic behavior for the locked code sequence.
3.19 Data Cache
For fast, single cycle data access, the RM5231 includes a 32 KB on-chip data cache that is two-
way set associative with a fixed 32-byte (eight words) line size.
The data cache is protected with byte parity and its tag is protected with a single parity bit. It is
virtually indexed and physically tagged to allow simultaneous address translation and data cache
access.
Cache protocols supported for the data cache are:
1. Uncached
Data loads and instruction fetches from uncached memory space are brought in from the main
memory to the register file and the execution unit, respectfully. The caches are not accessed.
Data stores to uncached memory space go directly to the main memory without updating the
data cache.
2. Write-back
Loads and instruction fetches first search the cache, reading main memory only if the desired
data is not cache resident. On data store operations, the cache is first searched to determine if
the target address is cache resident. If it is resident, the cache contents are updated, and the
cache line is marked for later write-back. If the cache lookup misses, the target cache line is
first brought into the cache and then the write is performed as above.
3. Write-through with write allocate
Loads and instruction fetches first search the cache, reading main memory only if the desired
data is not cache resident. On data store operations, the cache is first searched to determine if
the target address is cache resident. If it is resident, the cache contents are updated and main
memory is written, leaving the
write-back
bit of the cache line unchanged. If the cache lookup
misses, the target line is first brought into the cache and then the write is performed as above.
相關(guān)PDF資料
PDF描述
RM5231 RM5231⑩ Microprocessor with 32-Bit System Bus Data Sheet Released
RM5231-200-Q RM5231⑩ Microprocessor with 32-Bit System Bus Data Sheet Released
RM5231-250-Q RM5231⑩ Microprocessor with 32-Bit System Bus Data Sheet Released
RM5231A RM5231A⑩ Microprocessor with 32-Bit System Bus Data Sheet Preliminary
RM5231A-250-H RM5231A⑩ Microprocessor with 32-Bit System Bus Data Sheet Preliminary
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
RM5231-150Q-C001 制造商:PMC-Sierra 功能描述:
RM5231-200Q 制造商:未知廠家 制造商全稱:未知廠家 功能描述:64-Bit Microprocessor
RM5231-225Q 制造商:未知廠家 制造商全稱:未知廠家 功能描述:64-Bit Microprocessor
RM5231-250Q 制造商:QED 功能描述:Microprocessor, 64 Bit, 128 Pin, Plastic, QFP
RM5231A 制造商:PMC 制造商全稱:PMC 功能描述:64-Bit MIPS RISC Microprocessor with 32/64-Bit System Bus