ARM Compiler toolchain Using the Linker - ARM Information Center

7.18 Symdefs file format
7.18.1 Example symdefs file
Accessing and managing symbols with armlink
The symdefs file defines symbols and their values. The file consists of:
Identification line
The identification line in a symdefs file comprises:
• an identifying string, ##, which must be the first 11 characters in
the file for the linker to recognize it as a symdefs file
• linker version information, in the format:
ARM Linker, ARMCCver [Build num]:
• date and time of the most recent update of the symdefs file, in the format:
Last Updated: Date
The version and update information are not part of the identifying string.
Comments You can insert comments manually with a text editor. Comments have the
following properties:
• The first line must start with the special identifying comment ##.
This comment is inserted by the linker when the file is produced and must
not be manually deleted.
• Any line where the first non-whitespace character is a semicolon (;) or hash
(#) is a comment.
• A semicolon (;) or hash (#) after the first non-whitespace character does not
start a comment.
• Blank lines are ignored and can be inserted to improve readability.
Symbol information
The symbol information is provided on a single line, and comprises:
Symbol value The linker writes the absolute address of the symbol in fixed
hexadecimal format, for example, 0x00008000. If you edit
the file, you can use either hexadecimal or decimal formats
for the address value.
Type flag A single letter to show symbol type:
A ARM code
T Thumb code
D Data
N Number.
Symbol name The symbol name.
This example shows a typical symdefs file format:
## ARM Linker, ARMCC41 [Build num]: Last Updated: Date
;value type name, this is an added comment
0x00008000 A __main
0x00008004 A __scatterload
0x000080E0 T main
0x0000814D T _main_arg
Example 7-3 Symdefs file format
ARM DUI 0474C Copyright © 2010-2011 ARM. All rights reserved. 7-21
ID080411 Non-Confidential