ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Introduction to the ARM Architecture
A1.4 Architecture extensions
This manual describes the following extensions to the ARM and Thumb instruction set architectures:
ThumbEE Is a variant of the Thumb instruction set that is designed as a target for dynamically
generated code. It is:
a required extension to the ARMv7-A profile
an optional extension to the ARMv7-R profile.
VFP Is a floating-point coprocessor extension to the instruction set architectures. There
have been three main versions of VFP to date:
VFPv1 is obsolete. Details are available on request from ARM.
VFPv2 is an optional extension to:
— the ARM instruction set in the ARMv5TE, ARMv5TEJ, ARMv6, and
ARMv6K architectures
— the ARM and Thumb instruction sets in the ARMv6T2 architecture.
VFPv3 is an optional extension to the ARM, Thumb and ThumbEE
instruction sets in the ARMv7-A and ARMv7-R profiles.
VFPv3 can be implemented with either thirty-two or sixteen doubleword
registers, as described in Advanced SIMD and VFP extension registers on
page A2-21. Where necessary, the terms VFPv3-D32 and VFPv3-D16 are
used to distinguish between these two implementation options. Where the
term VFPv3 is used it covers both options.
VFPv3 can be extended by the half-precision extensions that provide
conversion functions in both directions between half-precision floating-point
and single-precision floating-point.
Advanced SIMD Is an instruction set extension that provides Single Instruction Multiple Data
(SIMD) functionality. It is an optional extension to the ARMv7-A and ARMv7-R
profiles. When VFPv3 and Advanced SIMD are both implemented, they use a
shared register bank and have some shared instructions.
Advanced SIMD can be extended by the half-precision extensions that provide
conversion functions in both directions between half-precision floating-point and
single-precision floating-point.
Security Extensions Are a set of security features that facilitate the development of secure applications.
They are an optional extension to the ARMv6K architecture and the ARMv7-A
profile.
Jazelle Is the Java bytecode execution extension that extended ARMv5TE to ARMv5TEJ.
From ARMv6 Jazelle is a required part of the architecture, but is still often
described as the Jazelle extension.
Multiprocessing Extensions
Are a set of features that enhance multiprocessing functionality. They are an
optional extension to the ARMv7-A and ARMv7-R profiles.
A1-6 Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. ARM DDI 0406B