ARM Architecture Reference Manual Thumb-2 Supplement

1 Copyright 2004, 2005 ARM Limited. All rights DDI 0308 DARM ArchitectureReference ManualThumb-2 Supplement iiCopyright 2004, 2005 ARM Limited. All rights DDI 0308 DARM Architecture Reference ManualCopyright 2004, 2005 ARM Limited. All rights InformationThe following changes have been made to this NoticeARM, the ARM Powered logo, Thumb, and StrongARM are registered trademarks of ARM ARM logo, AMBA, Angel, ARMulator, EmbeddedICE, ModelGen, Multi-ICE, PrimeCell, ARM7 TDMI, ARM7 TDMI-S, ARM9 TDMI, ARM9E-S, ETM7, ETM9, TDMI, STRONG, are trademarks of ARM other products or services mentioned herein may be trademarks of their respective product described in this document is subject to continuous developments and improvements.

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6 IvCopyright 2004, 2005 ARM Limited. All rights DDI 0308 DARM DDI 0308 DCopyright 2004, 2005 ARM Limited. All rights Architecture Reference Manual Thumb-2 SupplementPrefaceAbout this Manual .. viiiUnified Assembler Language .. ixUsing this Manual .. xConventions .. xiFurther reading .. xiiFeedback .. xiiiChapter 1 Introduction to Thumb-2 .. to Thumb assembly language syntax .. 32-bit Thumb instructions .. 16-bit Thumb instructions .. 32-bit ARM instructions .. instructions .. Architecture constraints .. 1-9 Chapter 2 Programmers program status register fields.

7 To exception handling .. 2-4 ContentsviCopyright 2004, 2005 ARM Limited. All rights DDI fast interrupt support .. and reset handling in Thumb state .. access support .. support .. stores and exclusive access .. divide support .. 2-15 Chapter 3 The Thumb Instruction set encoding .. encoding for 16-bit Thumb instructions .. encoding for 32-bit Thumb instructions .. execution .. and UNPREDICTABLE instruction set space .. of 0b1111 as a register specifier in 32-bit encodings .. of 0b1101 as a register specifier .. and VFP support.

8 3-43 Chapter 4 Thumb of instruction descriptions .. constants .. shifts applied to a register .. accesses .. hints .. list of Thumb instructions .. 4-15 Chapter 5 New ARM list of new ARM instructions .. 5-2 Appendix APseudo-code encoding diagrams and pseudo-code .. Types .. and built-in functions .. and program structure .. procedures and functions .. A-22 GlossaryARM DDI 0308 DCopyright 2004, 2005 ARM Limited. All rights preface describes the contents of this Manual , then lists the conventions and terminology it uses.

9 About this Manual on page viii Unified Assembler Language on page ix Using this Manual on page x Conventions on page xi Further reading on page xii Feedback on page viiiCopyright 2004, 2005 ARM Limited. All rights DDI 0308 DAbout this manualThe purpose of this Manual is to describe Thumb -2, its Instruction Set Architecture (ISA), and the changes to the programmers model it introduces. This Manual also describes the extensions to the ARM ISA introduced at the same time. Thumb-2 is a superset of the ARMv6 Thumb ISA described in the ARM Architecture Reference Manual (ARM DDI 0100).

10 Thumb-2 extends the Thumb Architecture by adding the following: A substantial number of new 32-bit Thumb instructions. These cover most of the functionality of the ARM instruction set. The main omission is the absence of a condition field in almost all Thumb instructions. Several new 16-bit Thumb instructions. One of these, the IT (If Then) instruction, provides an efficient alternative mechanism for conditional also extends the ARM ISA by adding a small number of new ARM instructions, and some additional variants of the ARM LDR and STR instructions. The additions provide ARM equivalents of instructions supported in the Thumb instruction precise effects of each new instruction are described, including any restrictions on its use.