• Using as
• Overview
  • Structure of this Manual
  • The GNU Assembler
  • Object File Formats
  • Command Line
  • Input Files
  • Output (Object) File
  • Error and Warning Messages
• Command-Line Options
  • Enable Listings: -a[cdghlns]
  • --alternate
  • -D
  • Work Faster: -f
  • .include Search Path: -I path
  • Difference Tables: -K
  • Include Local Symbols: -L
  • Configuring listing output: --listing
  • Assemble in MRI Compatibility Mode: -M
  • Dependency Tracking: --MD
  • Name the Object File: -o
  • Join Data and Text Sections: -R
  • Display Assembly Statistics: --statistics
  • Compatible Output: --traditional-format
  • Announce Version: -v
  • Control Warnings: -W, --warn, --no-warn, --fatal-warnings
  • Generate Object File in Spite of Errors: -Z
• Syntax
  • Preprocessing
  • Whitespace
  • Comments
  • Symbols
  • Statements
  • Constants
    • Character Constants
      • Strings
      • Characters
    • Number Constants
      • Integers
      • Bignums
      • Flonums
• Sections and Relocation
  • Background
  • Linker Sections
  • Assembler Internal Sections
  • Sub-Sections
  • bss Section
• Symbols
  • Labels
  • Giving Symbols Other Values
  • Symbol Names
  • The Special Dot Symbol
  • Symbol Attributes
    • Value
    • Type
    • Symbol Attributes: a.out
      • Descriptor
      • Other
    • Symbol Attributes for COFF
      • Primary Attributes
      • Auxiliary Attributes
    • Symbol Attributes for SOM
• Expressions
  • Empty Expressions
  • Integer Expressions
    • Arguments
    • Operators
    • Prefix Operator
    • Infix Operators
• Assembler Directives
  • .abort
  • .ABORT (COFF)
  • .align abs-expr, abs-expr, abs-expr
  • .ascii "string"...
  • .asciz "string"...
  • .balign[wl] abs-expr, abs-expr, abs-expr
  • .byte expressions
  • .comm symbol , length
  • .cfi_startproc [simple]
  • .cfi_endproc
  • .cfi_personality encoding [, exp]
  • .cfi_lsda encoding [, exp]
  • .cfi_def_cfa register, offset
  • .cfi_def_cfa_register register
  • .cfi_def_cfa_offset offset
  • .cfi_adjust_cfa_offset offset
  • .cfi_offset register, offset
  • .cfi_rel_offset register, offset
  • .cfi_register register1, register2
  • .cfi_restore register
  • .cfi_undefined register
  • .cfi_same_value register
  • .cfi_remember_state,
  • .cfi_return_column register
  • .cfi_signal_frame
  • .cfi_window_save
  • .cfi_escape expression[, ...]
  • .cfi_val_encoded_addr register, encoding, label
  • .file fileno filename
  • .loc fileno lineno [column] [options]
  • .loc_mark_labels enable
  • .data subsection
  • .def name
  • .desc symbol, abs-expression
  • .dim
  • .double flonums
  • .eject
  • .else
  • .elseif
  • .end
  • .endef
  • .endfunc
  • .endif
  • .equ symbol, expression
  • .equiv symbol, expression
  • .eqv symbol, expression
  • .err
  • .error
  • .exitm
  • .extern
  • .fail expression
  • .file string
  • .fill repeat , size , value
  • .float flonums
  • .func name[,label]
  • .global symbol, .globl symbol
  • .gnu_attribute tag,value
  • .hidden names
  • .hword expressions
  • .ident
  • .if absolute expression
  • .incbin "file"[,skip[,count]]
  • .include "file"
  • .int expressions
  • .internal names
  • .irp symbol,values...
  • .irpc symbol,values...
  • .lcomm symbol , length
  • .lflags
  • .line line-number
  • .linkonce [type]
  • .ln line-number
  • .mri val
  • .list
  • .long expressions
  • .macro
  • .altmacro
  • .noaltmacro
  • .nolist
  • .octa bignums
  • .org new-lc , fill
  • .p2align[wl] abs-expr, abs-expr, abs-expr
  • .previous
  • .popsection
  • .print string
  • .protected names
  • .psize lines , columns
  • .purgem name
  • .pushsection name [, subsection] [, "flags"[, @type[,arguments]]]
  • .quad bignums
  • .reloc offset, reloc_name[, expression]
  • .rept count
  • .sbttl "subheading"
  • .scl class
  • .section name
  • .set symbol, expression
  • .short expressions
  • .single flonums
  • .size
  • .sleb128 expressions
  • .skip size , fill
  • .space size , fill
  • .stabd, .stabn, .stabs
  • .string "str", .string8 "str", .string16
  • .struct expression
  • .subsection name
  • .symver
  • .tag structname
  • .text subsection
  • .title "heading"
  • .type
  • .uleb128 expressions
  • .val addr
  • .version "string"
  • .vtable_entry table, offset
  • .vtable_inherit child, parent
  • .warning "string"
  • .weak names
  • .weakref alias, target
  • .word expressions
  • Deprecated Directives
• Object Attributes
  • gnu Object Attributes
    • Common gnu attributes
    • MIPS Attributes
    • PowerPC Attributes
  • Defining New Object Attributes
• Machine Dependent Features
  • Alpha Dependent Features
    • Notes
    • Options
    • Syntax
      • Special Characters
      • Register Names
      • Relocations
    • Floating Point
    • Alpha Assembler Directives
    • Opcodes
  • ARC Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Register Names
    • Floating Point
    • ARC Machine Directives
    • Opcodes
  • ARM Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Register Names
    • Floating Point
      • ARM relocation generation
    • ARM Machine Directives
    • Opcodes
    • Mapping Symbols
    • Unwinding
  • AVR Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Register Names
      • Relocatable Expression Modifiers
    • Opcodes
  • AVR32 Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Symbol references
      • Symbol modifiers
    • Directives
    • Opcodes
  • Blackfin Dependent Features
    • Syntax
    • Directives
  • CR16 Dependent Features
    • CR16 Operand Qualifiers
  • CRIS Dependent Features
    • Command-line Options
    • Instruction expansion
    • Symbols
    • Syntax
      • Special Characters
      • Symbols in position-independent code
      • Register names
      • Assembler Directives
  • D10V Dependent Features
    • D10V Options
    • Syntax
      • Size Modifiers
      • Sub-Instructions
      • Special Characters
      • Register Names
      • Addressing Modes
      • @WORD Modifier
    • Floating Point
    • Opcodes
  • D30V Dependent Features
    • D30V Options
    • Syntax
      • Size Modifiers
      • Sub-Instructions
      • Special Characters
      • Guarded Execution
      • Register Names
      • Addressing Modes
    • Floating Point
    • Opcodes
  • H8/300 Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Register Names
      • Addressing Modes
    • Floating Point
    • H8/300 Machine Directives
    • Opcodes
  • HPPA Dependent Features
    • Notes
    • Options
    • Syntax
    • Floating Point
    • HPPA Assembler Directives
    • Opcodes
  • ESA/390 Dependent Features
    • Notes
    • Options
    • Syntax
    • Floating Point
    • ESA/390 Assembler Directives
    • Opcodes
  • 80386 Dependent Features
    • Options
    • x86 specific Directives
    • AT&T Syntax versus Intel Syntax
    • Instruction Naming
    • AT&T Mnemonic versus Intel Mnemonic
    • Register Naming
    • Instruction Prefixes
    • Memory References
    • Handling of Jump Instructions
    • Floating Point
    • Intel's MMX and AMD's 3DNow! SIMD Operations
    • Writing 16-bit Code
    • AT&T Syntax bugs
    • Specifying CPU Architecture
    • Notes
  • Intel i860 Dependent Features
    • i860 Notes
    • i860 Command-line Options
      • SVR4 compatibility options
      • Other options
    • i860 Machine Directives
    • i860 Opcodes
      • Other instruction support (pseudo-instructions)
  • Intel 80960 Dependent Features
    • i960 Command-line Options
    • Floating Point
    • i960 Machine Directives
    • i960 Opcodes
      • callj
      • Compare-and-Branch
  • IA-64 Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Register Names
      • IA-64 Processor-Status-Register (PSR) Bit Names
    • Opcodes
  • IP2K Dependent Features
    • IP2K Options
  • M32C Dependent Features
    • M32C Options
    • Symbolic Operand Modifiers
  • M32R Dependent Features
    • M32R Options
    • M32R Directives
    • M32R Warnings
  • M680x0 Dependent Features
    • M680x0 Options
    • Syntax
    • Motorola Syntax
    • Floating Point
    • 680x0 Machine Directives
    • Opcodes
      • Branch Improvement
      • Special Characters
  • M68HC11 and M68HC12 Dependent Features
    • M68HC11 and M68HC12 Options
    • Syntax
    • Symbolic Operand Modifiers
    • Assembler Directives
    • Floating Point
    • Opcodes
      • Branch Improvement
  • MIPS Dependent Features
    • Assembler options
    • MIPS ECOFF object code
    • Directives for debugging information
    • Directives to override the size of symbols
    • Directives to override the ISA level
    • Directives for extending MIPS 16 bit instructions
    • Directive to mark data as an instruction
    • Directives to save and restore options
    • Directives to control generation of MIPS ASE instructions
    • Directives to override floating-point options
  • MMIX Dependent Features
    • Command-line Options
    • Instruction expansion
    • Syntax
      • Special Characters
      • Symbols
      • Register names
      • Assembler Directives
    • Differences to mmixal
  • MSP 430 Dependent Features
    • Options
    • Syntax
      • Macros
      • Special Characters
      • Register Names
      • Assembler Extensions
    • Floating Point
    • MSP 430 Machine Directives
    • Opcodes
    • Profiling Capability
  • PDP-11 Dependent Features
    • Options
      • Code Generation Options
      • Instruction Set Extension Options
      • CPU Model Options
      • Machine Model Options
    • Assembler Directives
    • PDP-11 Assembly Language Syntax
    • Instruction Naming
    • Synthetic Instructions
  • picoJava Dependent Features
    • Options
  • PowerPC Dependent Features
    • Options
    • PowerPC Assembler Directives
  • Renesas / SuperH SH Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Register Names
      • Addressing Modes
    • Floating Point
    • SH Machine Directives
    • Opcodes
  • SuperH SH64 Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Register Names
      • Addressing Modes
    • SH64 Machine Directives
    • Opcodes
  • SPARC Dependent Features
    • Options
    • Enforcing aligned data
    • Sparc Syntax
      • Special Characters
      • Register Names
      • Constants
      • Relocations
      • Size Translations
    • Floating Point
    • Sparc Machine Directives
  • TIC54X Dependent Features
    • Options
    • Blocking
    • Environment Settings
    • Constants Syntax
    • String Substitution
    • Local Labels
    • Math Builtins
    • Extended Addressing
    • Directives
    • Macros
    • Memory-mapped Registers
  • Z80 Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Register Names
      • Case Sensitivity
    • Floating Point
    • Z80 Assembler Directives
    • Opcodes
  • Z8000 Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Register Names
      • Addressing Modes
    • Assembler Directives for the Z8000
    • Opcodes
  • VAX Dependent Features
    • VAX Command-Line Options
    • VAX Floating Point
    • Vax Machine Directives
    • VAX Opcodes
    • VAX Branch Improvement
    • VAX Operands
    • Not Supported on VAX
  • v850 Dependent Features
    • Options
    • Syntax
      • Special Characters
      • Register Names
    • Floating Point
    • V850 Machine Directives
    • Opcodes
  • Xtensa Dependent Features
    • Command Line Options
    • Assembler Syntax
      • Opcode Names
      • Register Names
    • Xtensa Optimizations
      • Using Density Instructions
      • Automatic Instruction Alignment
    • Xtensa Relaxation
      • Conditional Branch Relaxation
      • Function Call Relaxation
      • Other Immediate Field Relaxation
    • Directives
      • schedule
      • longcalls
      • transform
      • literal
      • literal_position
      • literal_prefix
      • absolute-literals
• Reporting Bugs
  • Have You Found a Bug?
  • How to Report Bugs
• Acknowledgements