Using as

The GNU Assembler

January 1994

• Overview
  • Structure of this Manual
  • as, the GNU Assembler
  • Object File Formats
  • Command Line
  • Input Files
  • Output (Object) File
  • Error and Warning Messages
• Command-Line Options
  • Enable Listings: -a[dhlns]
  • -D
  • Work Faster: -f
  • .include search path: -I path
  • Difference Tables: -K
  • Include Local Labels: -L
  • Assemble in MRI Compatibility Mode: -M
  • Name the Object File: -o
  • Join Data and Text Sections: -R
  • Display Assembly Statistics: --statistics
  • Announce Version: -v
  • Suppress Warnings: -W
  • 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
  • ld Sections
  • as 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
  • .align abs-expr , abs-expr
  • .app-file string
  • .ascii "string"...
  • .asciz "string"...
  • .balign abs-expr , abs-expr
  • .byte expressions
  • .comm symbol , length
  • .data subsection
  • .def name
  • .desc symbol, abs-expression
  • .dim
  • .double flonums
  • .eject
  • .else
  • .endef
  • .endif
  • .equ symbol, expression
  • .extern
  • .file string
  • .fill repeat , size , value
  • .float flonums
  • .global symbol, .globl symbol
  • .hword expressions
  • .ident
  • .if absolute expression
  • .include "file"
  • .int expressions
  • .irp symbol,values...
  • .irpc symbol,values...
  • .lcomm symbol , length
  • .lflags
  • .line line-number
  • .ln line-number
  • .list
  • .long expressions
  • .macro
  • .nolist
  • .octa bignums
  • .org new-lc , fill
  • .p2align abs-expr , abs-expr
  • .psize lines , columns
  • .quad bignums
  • .rept count
  • .sbttl "subheading"
  • .scl class
  • .section name, subsection
  • .set symbol, expression
  • .short expressions
  • .single flonums
  • .size
  • .space size , fill
  • .stabd, .stabn, .stabs
  • .string "str"
  • .tag structname
  • .text subsection
  • .title "heading"
  • .type int
  • .val addr
  • .word expressions
  • Deprecated Directives
• Machine Dependent Features
• VAX Dependent Features
  • VAX Command-Line Options
  • VAX Floating Point
  • Vax Machine Directives
  • VAX Opcodes
  • VAX Branch Improvement
  • VAX Operands
  • Not Supported on VAX
• AMD 29K Dependent Features
  • Options
  • Syntax
    • Special Characters
    • Register Names
  • Floating Point
  • AMD 29K Machine Directives
  • Opcodes
• H8/300 Dependent Features
  • Options
  • Syntax
    • Special Characters
    • Register Names
    • Addressing Modes
  • Floating Point
  • H8/300 Machine Directives
  • Opcodes
• H8/500 Dependent Features
  • Options
  • Syntax
    • Special Characters
    • Register Names
    • Addressing Modes
  • Floating Point
  • H8/500 Machine Directives
  • Opcodes
• HPPA Dependent Features
  • Notes
  • Options
  • Syntax
  • Floating Point
  • HPPA Assembler Directives
  • Opcodes
• Hitachi SH Dependent Features
  • Options
  • Syntax
    • Special Characters
    • Register Names
    • Addressing Modes
  • Floating Point
  • SH Machine Directives
  • Opcodes
• Intel 80960 Dependent Features
  • i960 Command-line Options
  • Floating Point
  • i960 Machine Directives
  • i960 Opcodes
    • callj
    • Compare-and-Branch
• M680x0 Dependent Features
  • M680x0 Options
  • Syntax
  • Motorola Syntax
  • Floating Point
  • 680x0 Machine Directives
  • Opcodes
    • Branch Improvement
    • Special Characters
• SPARC Dependent Features
  • Options
  • Floating Point
  • Sparc Machine Directives
• 80386 Dependent Features
  • Options
  • AT&T Syntax versus Intel Syntax
  • Opcode Naming
  • Register Naming
  • Opcode Prefixes
  • Memory References
  • Handling of Jump Instructions
  • Floating Point
  • Writing 16-bit Code
  • Notes
• Z8000 Dependent Features
  • Options
  • Syntax
    • Special Characters
    • Register Names
    • Addressing Modes
  • Assembler Directives for the Z8000
  • Opcodes
• MIPS Dependent Features
  • Assembler options
  • MIPS ECOFF object code
  • Directives for debugging information
  • Directives to override the ISA level
• Acknowledgements
• Index
• Footnotes