RealView Compilation Tools Compiler Reference Guide - ARM ...

Compiler-specific Features
Restrictions
A function that is declared as pure can have no side effects. For example, pure functions:
• cannot call impure functions
• cannot use global variables or dereference pointers, because the compiler
assumes that the function does not access memory, except stack memory
• must return the same value each time when called twice with the same
parameters.
Example
int factr(int n) __pure
{
int f = 1;
}
while (n > 0)
f *= n--;
return f;
See also
• __attribute__((const)) on page 4-31
• __pure on page 4-15 in the Compiler User Guide
• Placing ARM function qualifiers on page 4-17 in the Compiler User Guide.
4.1.13 __smc
The __smc keyword declares an SMC (Secure Monitor Call) function. A call to the SMC
function inserts an SMC instruction into the instruction stream generated by the compiler
at the point of function invocation.
Note
The SMC instruction replaces the SMI instruction used in previous versions of the ARM
assembly language.
__smc is a function qualifier. It affects the type of a function.
Syntax
__smc(int smc_num) return-type function-name([argument-list]);
4-14 Copyright © 2007, 2010 ARM Limited. All rights reserved. ARM DUI 0348A
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