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Glossary
Big-endian
Big-endian memory
Boundary scan chain
Branch folding
Breakpoint
Burst
Byte
Byte-invariant
Glossary-4
Byte ordering scheme in which bytes of decreasing significance in a data word are
stored at increasing addresses in memory.
See also Little-endian and Endianness.
Memory in which:
•
a byte or halfword at a word-aligned address is the most significant byte or
halfword within the word at that address
•
a byte at a halfword-aligned address is the most significant byte within the
halfword at that address.
See also Little-endian memory.
A boundary scan chain is made up of serially-connected devices that implement
boundary scan technology using a standard JTAG TAP interface. Each device contains
at least one TAP controller containing shift registers that form the chain connected
between TDI and TDO, through which test data is shifted. Processors can contain
several shift registers to enable you to access selected parts of the device.
Branch folding is a technique where the branch instruction is completely removed from
the instruction stream presented to the execution pipeline.
A breakpoint is a mechanism provided by debuggers to identify an instruction at which
program execution is to be halted. Breakpoints are inserted by the programmer to enable
inspection of register contents, memory locations, variable values at fixed points in the
program execution to test that the program is operating correctly. Breakpoints are
removed after the program is successfully tested.
See also Watchpoint.
A group of transfers to consecutive addresses. Because the addresses are consecutive,
there is no requirement to supply an address for any of the transfers after the first one.
This increases the speed at which the group of transfers can occur. Bursts over AMBA
are controlled using signals to indicate the length of the burst and how the addresses are
incremented.
See also Beat.
An 8-bit data item.
In a byte-invariant system, the address of each byte of memory remains unchanged
when switching between little-endian and big-endian operation. When a data item
larger than a byte is loaded from or stored to memory, the bytes making up that data item
are arranged into the correct order depending on the endianness of the memory access.
Copyright © 2005, 2006 ARM Limited. All rights reserved.
ARM DDI 0337B
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