ARM ARM926EJ-S Technical Reference Manual page 242

Glossary
Unpredictable
VA
Victim
Virtual Address (VA)
Warm reset
Watchpoint
Way
WB
Word
Write
Write-back (WB)
Write buffer
Glossary-18
For reads, the data returned when reading from this location is unpredictable. It can have
any value. For writes, writing to this location causes unpredictable behavior, or an
unpredictable change in device configuration. Unpredictable instructions must not halt
or hang the processor, or any part of the system.
See Virtual Address.
A cache line, selected to be discarded to make room for a replacement cache line that is
required as a result of a cache miss. The way in which the victim is selected for eviction
is processor-specific. A victim is also known as a cast out.
The MMU uses its page tables to translate a Virtual Address into a Physical Address.
The processor executes code at the Virtual Address, which might be located elsewhere
in physical memory.
See also Fast Context Switch Extension, Modified Virtual Address, and Physical
Address.
Also known as a core reset. Initializes the majority of the processor excluding the debug
controller and debug logic. This type of reset is useful if you are using the debugging
features of a processor.
A watchpoint is a mechanism provided by debuggers to halt program execution when
the data contained by a particular memory address is changed. Watchpoints are inserted
by the programmer to allow inspection of register contents, memory locations, and
variable values when memory is written to test that the program is operating correctly.
Watchpoints are removed after the program is successfully tested. See also Breakpoint.
See Cache way.
See Write-back.
A 32-bit data item.
Writes are defined as operations that have the semantics of a store. That is, the ARM
instructions SRS, STM, STRD, STC, STRT, STRH, STRB, STRBT, STREX, SWP, and
SWPB, and the Thumb instructions STM, STR, STRH, STRB, and PUSH. Java
instructions that are accelerated by hardware can cause a number of writes to occur,
according to the state of the Java stack and the implementation of the Java hardware
acceleration.
In a write-back cache, data is only written to main memory when it is forced out of the
cache on line replacement following a cache miss. Otherwise, writes by the processor
only update the cache. (Also known as copyback).
A block of high-speed memory, arranged as a FIFO buffer, between the data cache and
main memory, whose purpose is to optimize stores to main memory.
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