RealView Compilation Tools Compiler Reference Guide - ARM ...

Language Extensions
3.6.4 Assembler labels
Assembler labels specify the assembler name to use for a C symbol. For example, you
might have assembler code and C code that uses the same symbol name, such as
counter. Therefore, you can export a different name to be used by the assembler:
int counter __asm__("counter_v1") = 0;
This exports the symbol counter_v1 and not the symbol counter.
See also
• __asm on page 4-5.
3.6.5 Empty declaration
An empty declaration, that is a semicolon with nothing before it, is permitted.
Example
; // do nothing
3.6.6 Hexadecimal floating-point constants
The ARM compiler implements an extension to the syntax of numeric constants in C to
enable explicit specification of floating-point constants as IEEE bit patterns.
Syntax
The syntax for specifying floating-point constants as IEEE bit patterns is:
0f_n
0d_nn
Interpret an 8-digit hex number n as a float constant. There must be
exactly eight digits.
Interpret a 16-digit hex number nn as a double constant. There must be
exactly 16 digits.
3.6.7 Incomplete enums
Forward declarations of enums are supported.
Example
enum Incomplete_Enums_0;
int Incomplete_Enums_2 (enum Incomplete_Enums_0 * passon)
ARM DUI 0348A Copyright © 2007, 2010 ARM Limited. All rights reserved. 3-21
Non-Confidential