Table of Contents

1. Using as ............................................................................................................................................ 1

2. Overview .......................................................................................................................................... 3

2.1. Structure of this Manual................................................................................................... 15

2.2. The GNU Assembler........................................................................................................ 15

2.3. Object File Formats.......................................................................................................... 15

2.4. Command Line................................................................................................................. 16

2.5. Input Files ........................................................................................................................ 16

2.5.1. Filenames and Line numbers............................................................................ 16

2.6. Output (Object) File......................................................................................................... 17

2.7. Error and Warning Messages ........................................................................................... 17

3. Command Line Options............................................................................................................... 19

3.1. Enable Listings:

 a[cdhlns]

......................................................................................... 19

3.2.

 alternate

.................................................................................................................... 19

3.3.

 D

..................................................................................................................................... 19

3.4. Work Faster:

 f

................................................................................................................ 20

3.5.

.include

Search Path:

 Ipath

...................................................................................... 20

3.6. Difference Tables:

 K

....................................................................................................... 20

3.7. Include Local Labels:

 L

................................................................................................. 20

3.8. Configuring listing output:

 listing

............................................................................. 20

3.9. Assemble in MRI Compatibility Mode:

 M

..................................................................... 21

3.10. Dependency Tracking:

 MD

............................................................................................ 22

3.11. Name the Object File:

 o

............................................................................................... 23

3.12. Join Data and Text Sections:

 R

..................................................................................... 23

3.13. Display Assembly Statistics:

 statistics

................................................................. 23

3.14. Compatible Output:

 traditional format

.............................................................. 23

3.15. Announce Version:

 v

................................................................................................... 23

3.16. Control Warnings:

 W

,

 warn

,

 no warn

,

 fatal warnings

.................................. 23

3.17. Generate Object File in Spite of Errors:

 Z

................................................................... 24

4. Syntax............................................................................................................................................. 25

4.1. Preprocessing ................................................................................................................... 25

4.2. Whitespace....................................................................................................................... 25

4.3. Comments ........................................................................................................................ 25

4.4. Symbols ........................................................................................................................... 26

4.5. Statements ........................................................................................................................ 26

4.6. Constants.......................................................................................................................... 27

4.6.1. Character Constants .......................................................................................... 27

4.6.2. Number Constants............................................................................................. 28

5. Sections and Relocation................................................................................................................ 31

5.1. Background ...................................................................................................................... 31

5.2. Linker Sections ................................................................................................................ 32

5.3. Assembler Internal Sections ............................................................................................ 33

5.4. Sub Sections .................................................................................................................... 33

5.5. bss Section ....................................................................................................................... 34

6. Symbols .......................................................................................................................................... 35

6.1. Labels............................................................................................................................... 35

6.2. Giving Symbols Other Values.......................................................................................... 35

6.3. Symbol Names ................................................................................................................. 35

6.3.1. Local Symbol Names........................................................................................ 35

6.3.2. Dollar Local Labels........................................................................................... 36

6.4. The Special Dot Symbol .................................................................................................. 37

6.5. Symbol Attributes ............................................................................................................ 37

6.5.1. Value ................................................................................................................. 37