-qasm
Category
Pragma equivalent
None.
Purpose
Controls the interpretation and subsequent generation of code for assembler language extensions.
When -qasm is in effect, the compiler generates code for assembly statements in the source code. Suboptions specify the syntax used to interpret the content of the assembly statement.
Syntax
-qasm syntax(for C) .-asm--+------------+-. | | .-gcc-. | | | '-=--+-----+-' | >>- -q--+-noasm---------------+--------------------------------><
Defaults
- -qasm=gcc
Parameters
- gcc
- Instructs the compiler to recognize the extended GCC syntax and semantics for assembly statements.
Specifying -qasm without a suboption is equivalent to specifying the default.
Usage
The token asm is not a C language keyword. Therefore, at language levels stdc89 and stdc99, which enforce strict compliance to the C89 and C99 standards, respectively, the option -qkeyword=asm must also be specified to compile source that generates assembly code. At all other language levels, token asm is treated as a keyword unless the option -qnokeyword=asm is in effect.
For detailed information about the syntax and semantics of inline asm statements, see Inline assembly statements.
Predefined macros
- __IBM_GCC_ASM is predefined to 1 when asm is recognized as a keyword and assembler code is generated; that is, at all language levels except stdc89 | stdc99, or when -qkeyword=asm is in effect, and when -qasm[=gcc] is in effect. It is predefined to 0 when asm is recognized as a keyword but assembler code is not generated; that is, at all language levels except stdc89 | stdc99, or when -qkeyword=asm is in effect, and when -qnoasm is in effect. It is undefined when the stdc89 | stdc99 language level or -qnokeyword=asm is in effect.
Examples
int a, b, c;
int main() {
asm("add %0, %1, %2" : "=r"(a) : "r"(b), "r"(c) );
}Related information
