ARM® Compiler v5.05 for µVision armasm User Guide

Version 5


Table of Contents

Preface
About this book
Using this book
Glossary
Typographic conventions
Feedback
Other information
1 Overview of the Assembler
1.1 About the ARM Compiler toolchain assemblers
1.2 Key features of the assembler
1.3 How the assembler works
1.4 Directives that can be omitted in pass 2 of the assembler
2 Overview of the ARM Architecture
2.1 About the ARM architecture
2.2 ARM, Thumb, and ThumbEE instruction sets
2.3 Changing between ARM, Thumb, and ThumbEE state
2.4 Processor modes, and privileged and unprivileged software execution
2.5 Processor modes in ARMv6-M and ARMv7-M
2.6 VFP hardware
2.7 ARM registers
2.8 General-purpose registers
2.9 Register accesses
2.10 Predeclared core register names
2.11 Predeclared extension register names
2.12 Predeclared coprocessor names
2.13 Program Counter
2.14 Application Program Status Register
2.15 The Q flag
2.16 Current Program Status Register
2.17 Saved Program Status Registers
2.18 ARM and Thumb instruction set overview
2.19 Access to the inline barrel shifter
3 Structure of Assembly Language Modules
3.1 Syntax of source lines in assembly language
3.2 Literals
3.3 ELF sections and the AREA directive
3.4 An example ARM assembly language module
4 Writing ARM Assembly Language
4.1 About the Unified Assembler Language
4.2 Register usage in subroutine calls
4.3 Load immediate values
4.4 Load immediate values using MOV and MVN
4.5 Load immediate values using MOV32
4.6 Load immediate values using LDR Rd, =const
4.7 Literal pools
4.8 Load addresses into registers
4.9 Load addresses to a register using ADR
4.10 Load addresses to a register using ADRL
4.11 Load addresses to a register using LDR Rd, =label
4.12 Other ways to load and store registers
4.13 Load and store multiple register instructions
4.14 Load and store multiple register instructions in ARM and Thumb
4.15 Stack implementation using LDM and STM
4.16 Stack operations for nested subroutines
4.17 Block copy with LDM and STM
4.18 Memory accesses
4.19 The Read-Modify-Write operation
4.20 Optional hash with immediate constants
4.21 About macros
4.22 Test-and-branch macro example
4.23 Unsigned integer division macro example
4.24 Instruction and directive relocations
4.25 Frame directives
4.26 Exception tables and Unwind tables
4.27 Assembly language changes after RVCT v2.1
5 Condition Codes
5.1 Conditional instructions
5.2 Conditional execution in ARM state
5.3 Conditional execution in Thumb state
5.4 Updates to the condition flags
5.5 Condition code suffixes
5.6 Comparison of condition code meanings in integer and floating-point code
5.7 Benefits of using conditional execution
5.8 Illustration of the benefits of using conditional instructions
5.9 Optimization for execution speed
6 Using the Assembler
6.1 Assembler command-line syntax
6.2 Specify command-line options with an environment variable
6.3 Overview of via files
6.4 Via file syntax rules
6.5 Using stdin to input source code to the assembler
6.6 Built-in variables and constants
6.7 Identifying versions of armasm in source code
6.8 Diagnostic messages
6.9 Interlocks diagnostics
6.10 Automatic IT block generation
6.11 Thumb branch target alignment
6.12 Thumb code size diagnostics
6.13 ARM and Thumb instruction portability diagnostics
6.14 Instruction width diagnostics
6.15 Two pass assembler diagnostics
6.16 Conditional assembly
6.17 Using the C preprocessor
6.18 Address alignment
6.19 Instruction width selection in Thumb
7 Symbols, Literals, Expressions, and Operators
7.1 Symbol naming rules
7.2 Variables
7.3 Numeric constants
7.4 Assembly time substitution of variables
7.5 Register-relative and PC-relative expressions
7.6 Labels
7.7 Labels for PC-relative addresses
7.8 Labels for register-relative addresses
7.9 Labels for absolute addresses
7.10 Numeric local labels
7.11 Syntax of numeric local labels
7.12 String expressions
7.13 String literals
7.14 Numeric expressions
7.15 Syntax of numeric literals
7.16 Syntax of floating-point literals
7.17 Logical expressions
7.18 Logical literals
7.19 Unary operators
7.20 Binary operators
7.21 Multiplicative operators
7.22 String manipulation operators
7.23 Shift operators
7.24 Addition, subtraction, and logical operators
7.25 Relational operators
7.26 Boolean operators
7.27 Operator precedence
7.28 Difference between operator precedence in assembly language and C
8 VFP Programming
8.1 Architecture support for VFP
8.2 Half-precision extension
8.3 Fused Multiply-Add extension
8.4 Extension register bank mapping
8.5 VFP views of the extension register bank
8.6 Load values to VFP registers
8.7 Conditional execution of VFP instructions
8.8 Floating-point exceptions
8.9 VFP data types
8.10 Extended notation
8.11 VFP system registers
8.12 Flush-to-zero mode
8.13 When to use flush-to-zero mode
8.14 The effects of using flush-to-zero mode
8.15 Operations not affected by flush-to-zero mode
8.16 VFP vector mode
8.17 Vectors in the VFP extension register bank
8.18 VFP vector wrap-around
8.19 VFP vector stride
8.20 Restriction on vector length
8.21 Control of scalar, vector, and mixed operations
8.22 Overview of VFP directives and vector notation
8.23 Pre-UAL VFP syntax and mnemonics
8.24 Vector notation
8.25 VFPASSERT SCALAR
8.26 VFPASSERT VECTOR
9 Assembler Command-line Options
9.1 --16
9.2 --32
9.3 --apcs=qualifier…qualifier
9.4 --arm
9.5 --arm_only
9.6 --bi
9.7 --bigend
9.8 --brief_diagnostics, --no_brief_diagnostics
9.9 --checkreglist
9.10 --compatible=name
9.11 --cpreproc
9.12 --cpreproc_opts=options
9.13 --cpu=list
9.14 --cpu=name
9.15 --debug
9.16 --depend=dependfile
9.17 --depend_format=string
9.18 --diag_error=tag[,tag,…]
9.19 --diag_remark=tag[,tag,…]
9.20 --diag_style={arm|ide|gnu}
9.21 --diag_suppress=tag[,tag,…]
9.22 --diag_warning=tag[,tag,…]
9.23 --dllexport_all
9.24 --dwarf2
9.25 --dwarf3
9.26 --errors=errorfile
9.27 --execstack, --no_execstack
9.28 --execute_only
9.29 --exceptions, --no_exceptions
9.30 --exceptions_unwind, --no_exceptions_unwind
9.31 --fpmode=model
9.32 --fpu=list
9.33 --fpu=name
9.34 -g
9.35 --help
9.36 -idir{,dir, …}
9.37 --keep
9.38 --length=n
9.39 --li
9.40 --library_type=lib
9.41 --liclinger=seconds
9.42 --licretry
9.43 --list=file
9.44 --list=
9.45 --littleend
9.46 -m
9.47 --maxcache=n
9.48 --md
9.49 --no_code_gen
9.50 --no_esc
9.51 --no_hide_all
9.52 --no_regs
9.53 --no_terse
9.54 --no_warn
9.55 -o filename
9.56 --pd
9.57 --predefine "directive"
9.58 --reduce_paths, --no_reduce_paths
9.59 --regnames=none
9.60 --regnames=callstd
9.61 --regnames=all
9.62 --report-if-not-wysiwyg
9.63 --show_cmdline
9.64 --split_ldm
9.65 --thumb
9.66 --thumbx
9.67 --unaligned_access, --no_unaligned_access
9.68 --unsafe
9.69 --untyped_local_labels
9.70 --version_number
9.71 --via=filename
9.72 --vsn
9.73 --width=n
9.74 --xref
10 ARM and Thumb Instructions
10.1 ARM and Thumb instruction summary
10.2 Instruction width specifiers
10.3 Flexible second operand (Operand2)
10.4 Syntax of Operand2 as a constant
10.5 Syntax of Operand2 as a register with optional shift
10.6 Shift operations
10.7 Saturating instructions
10.8 Condition codes
10.9 ADC
10.10 ADD
10.11 ADR (PC-relative)
10.12 ADR (register-relative)
10.13 ADRL pseudo-instruction
10.14 AND
10.15 ASR
10.16 B
10.17 BFC
10.18 BFI
10.19 BIC
10.20 BKPT
10.21 BL
10.22 BLX
10.23 BX
10.24 BXJ
10.25 CBZ and CBNZ
10.26 CDP and CDP2
10.27 CLREX
10.28 CLZ
10.29 CMP and CMN
10.30 CPS
10.31 CPY pseudo-instruction
10.32 DBG
10.33 DMB
10.34 DSB
10.35 EOR
10.36 ERET
10.37 HVC
10.38 ISB
10.39 IT
10.40 LDC and LDC2
10.41 LDM
10.42 LDR (immediate offset)
10.43 LDR (PC-relative)
10.44 LDR (register offset)
10.45 LDR (register-relative)
10.46 LDR pseudo-instruction
10.47 LDR, unprivileged
10.48 LDREX
10.49 LSL
10.50 LSR
10.51 MCR and MCR2
10.52 MCRR and MCRR2
10.53 MLA
10.54 MLS
10.55 MOV
10.56 MOV32 pseudo-instruction
10.57 MOVT
10.58 MRC and MRC2
10.59 MRRC and MRRC2
10.60 MRS (PSR to general-purpose register)
10.61 MRS (system coprocessor register to ARM register)
10.62 MSR (ARM register to system coprocessor register)
10.63 MSR (general-purpose register to PSR)
10.64 MUL
10.65 MVN
10.66 NEG pseudo-instruction
10.67 NOP
10.68 ORN (Thumb only)
10.69 ORR
10.70 PKHBT and PKHTB
10.71 PLD and PLI
10.72 POP
10.73 PUSH
10.74 QADD
10.75 QADD8
10.76 QADD16
10.77 QASX
10.78 QDADD
10.79 QDSUB
10.80 QSAX
10.81 QSUB
10.82 QSUB8
10.83 QSUB16
10.84 RBIT
10.85 REV
10.86 REV16
10.87 REVSH
10.88 RFE
10.89 ROR
10.90 RRX
10.91 RSB
10.92 RSC
10.93 SADD8
10.94 SADD16
10.95 SASX
10.96 SBC
10.97 SBFX
10.98 SDIV
10.99 SEL
10.100 SETEND
10.101 SEV
10.102 SHADD8
10.103 SHADD16
10.104 SHASX
10.105 SHSAX
10.106 SHSUB8
10.107 SHSUB16
10.108 SMC
10.109 SMLAxy
10.110 SMLAD
10.111 SMLAL
10.112 SMLALD
10.113 SMLALxy
10.114 SMLAWy
10.115 SMLSD
10.116 SMLSLD
10.117 SMMLA
10.118 SMMLS
10.119 SMMUL
10.120 SMUAD
10.121 SMULxy
10.122 SMULL
10.123 SMULWy
10.124 SMUSD
10.125 SRS
10.126 SSAT
10.127 SSAT16
10.128 SSAX
10.129 SSUB8
10.130 SSUB16
10.131 STC and STC2
10.132 STM
10.133 STR (immediate offset)
10.134 STR (register offset)
10.135 STR, unprivileged
10.136 STREX
10.137 SUB
10.138 SUBS pc, lr
10.139 SVC
10.140 SWP and SWPB
10.141 SXTAB
10.142 SXTAB16
10.143 SXTAH
10.144 SXTB
10.145 SXTB16
10.146 SXTH
10.147 SYS
10.148 TBB and TBH
10.149 TEQ
10.150 TST
10.151 UADD8
10.152 UADD16
10.153 UASX
10.154 UBFX
10.155 UDIV
10.156 UHADD8
10.157 UHADD16
10.158 UHASX
10.159 UHSAX
10.160 UHSUB8
10.161 UHSUB16
10.162 UMAAL
10.163 UMLAL
10.164 UMULL
10.165 UND pseudo-instruction
10.166 UQADD8
10.167 UQADD16
10.168 UQASX
10.169 UQSAX
10.170 UQSUB8
10.171 UQSUB16
10.172 USAD8
10.173 USADA8
10.174 USAT
10.175 USAT16
10.176 USAX
10.177 USUB8
10.178 USUB16
10.179 UXTAB
10.180 UXTAB16
10.181 UXTAH
10.182 UXTB
10.183 UXTB16
10.184 UXTH
10.185 WFE
10.186 WFI
10.187 YIELD
11 VFP Instructions
11.1 Summary of VFP instructions
11.2 VABS (floating-point)
11.3 VADD (floating-point)
11.4 VCMP, VCMPE
11.5 VCVT (between single-precision and double-precision)
11.6 VCVT (between floating-point and integer)
11.7 VCVT (between floating-point and fixed-point)
11.8 VCVTB, VCVTT (half-precision extension)
11.9 VDIV
11.10 VFMA, VFMS, VFNMA, VFNMS
11.11 VLDM
11.12 VLDR
11.13 VLDR (post-increment and pre-decrement)
11.14 VLDR pseudo-instruction
11.15 VMLA (floating-point)
11.16 VMLS (floating-point)
11.17 VMOV (floating-point)
11.18 VMOV (between one ARM register and single precision VFP)
11.19 VMOV (between two ARM registers and an extension register)
11.20 VMRS
11.21 VMSR
11.22 VMUL (floating-point)
11.23 VNEG (floating-point)
11.24 VNMLA (floating-point)
11.25 VNMLS (floating-point)
11.26 VNMUL (floating-point)
11.27 VPOP
11.28 VSQRT
11.29 VSTM
11.30 VSTR
11.31 VSTR (post-increment and pre-decrement)
11.32 VSUB (floating-point)
12 Directives Reference
12.1 Alphabetical list of directives
12.2 About assembly control directives
12.3 About frame directives
12.4 ALIAS
12.5 ALIGN
12.6 AREA
12.7 ARM or CODE32
12.8 ASSERT
12.9 ATTR
12.10 CN
12.11 CODE16
12.12 COMMON
12.13 CP
12.14 DATA
12.15 DCB
12.16 DCD and DCDU
12.17 DCDO
12.18 DCFD and DCFDU
12.19 DCFS and DCFSU
12.20 DCI
12.21 DCQ and DCQU
12.22 DCW and DCWU
12.23 DN and SN
12.24 END
12.25 ENDFUNC or ENDP
12.26 ENTRY
12.27 EQU
12.28 EXPORT or GLOBAL
12.29 EXPORTAS
12.30 FIELD
12.31 FRAME ADDRESS
12.32 FRAME POP
12.33 FRAME PUSH
12.34 FRAME REGISTER
12.35 FRAME RESTORE
12.36 FRAME RETURN ADDRESS
12.37 FRAME SAVE
12.38 FRAME STATE REMEMBER
12.39 FRAME STATE RESTORE
12.40 FRAME UNWIND ON
12.41 FRAME UNWIND OFF
12.42 FUNCTION or PROC
12.43 GBLA, GBLL, and GBLS
12.44 GET or INCLUDE
12.45 IF, ELSE, ENDIF, and ELIF
12.46 IMPORT and EXTERN
12.47 INCBIN
12.48 INFO
12.49 KEEP
12.50 LCLA, LCLL, and LCLS
12.51 LTORG
12.52 MACRO and MEND
12.53 MAP
12.54 MEXIT
12.55 NOFP
12.56 OPT
12.57 RELOC
12.58 REQUIRE
12.59 REQUIRE8 and PRESERVE8
12.60 RLIST
12.61 RN
12.62 ROUT
12.63 SETA, SETL, and SETS
12.64 SPACE or FILL
12.65 THUMB
12.66 THUMBX
12.67 TTL and SUBT
12.68 WHILE and WEND
13 Via File Syntax
13.1 Overview of via files
13.2 Via file syntax rules

List of Figures

2-1 Organization of general-purpose registers and Program Status Registers
8-1 Extension register bank
8-2 VFPv2 register banks
8-3 VFPv3 register banks
10-1 ASR #3
10-2 LSR #3
10-3 LSL #3
10-4 ROR #3
10-5 RRX

List of Tables

2-1 ARM processor modes
2-2 Predeclared core registers
2-3 Predeclared extension registers
2-4 Predeclared coprocessor registers
2-5 Instruction groups
4-1 ARM state immediate values (8-bit)
4-2 ARM state immediate values in MOV instructions
4-3 32-bit Thumb immediate values
4-4 32-bit Thumb immediate values in MOV instructions
4-5 Stack-oriented suffixes and equivalent addressing mode suffixes
4-6 Suffixes for load and store multiple instructions
4-7 Changes from earlier ARM assembly language
4-8 Relaxation of requirements
4-9 Differences between pre-UAL Thumb syntax and UAL syntax
5-1 Condition code suffixes
5-2 Condition codes
5-3 Conditional branches only
5-4 All instructions conditional
6-1 Built-in variables
6-2 Built-in Boolean constants
6-3 Predefined macros
6-4 {TARGET_ARCH_ARM} in relation to {TARGET_ARCH_THUMB}
6-5 Command-line options
6-6 armcc equivalent command-line options
7-1 Unary operators that return strings
7-2 Unary operators that return numeric or logical values
7-3 Multiplicative operators
7-4 String manipulation operators
7-5 Shift operators
7-6 Addition, subtraction, and logical operators
7-7 Relational operators
7-8 Boolean operators
7-9 Operator precedence in ARM assembly language
7-10 Operator precedence in C
8-1 VFP data type specifiers
8-2 Pre-UAL VFP mnemonics
8-3 Floating-point values for use with FCONST
9-1 Compatible processor or architecture combinations
9-2 Supported ARM architectures
9-3 Severity of diagnostic messages
9-4 Specifying a command-line option and an AREA directive for GNU-stack sections
10-1 Summary of ARM and Thumb instructions
10-2 Condition code suffixes
10-3 PC-relative offsets
10-4 Register-relative offsets
10-5 B instruction availability and range
10-6 BL instruction availability and range
10-7 BLX instruction availability and range
10-8 BX instruction availability and range
10-9 BXJ instruction availability and range
10-10 Offsets and architectures, LDR, word, halfword, and byte
10-11 PC-relative offsets
10-12 Options and architectures, LDR (register offsets)
10-13 Register-relative offsets
10-14 Offsets and architectures, LDR (User mode)
10-15 Offsets and architectures, STR, word, halfword, and byte
10-16 Options and architectures, STR (register offsets)
10-17 Offsets and architectures, STR (User mode)
10-18 Range and encoding of expr
11-1 Summary of VFP instructions
12-1 List of directives
12-2 OPT directive settings

Release Information

Document History
Issue Date Confidentiality Change
A May 2007 Non-Confidential Release for RVCT v3.1 for µVision
B December 2008 Non-Confidential Release for RVCT v4.0 for µVision
C June 2011 Non-Confidential Release for ARM Compiler v4.1 for µVision
D July 2012 Non-Confidential Release for ARM Compiler v5.02 for µVision
E 30 May 2014 Non-Confidential Release for ARM Compiler v5.04 for µVision
F 12 December 2014 Non-Confidential Release for ARM Compiler v5.05 for µVision

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