Commit d5fcd521 by Eric Coissac

Add a function to test indianness of the platform

parent 5138fe1d
/*
* littlebigman.c
*
* Created on: 23 mai 2015
* Author: coissac
*/
#include <littlebigman.h>
bool islittlend()
{
union { int entier;
char caractere[4] ;
} test;
test.entier=0x01020304;
return (test.caractere[3] == 1);
}
/*
* littlebigman.h
*
* Created on: 23 mai 2015
* Author: coissac
*/
#ifndef LITTLEBIGMAN_H_
#define LITTLEBIGMAN_H_
#include <stdbool.h>
/**
* Test is the architecture of the processor is little endian.
*
* ##Two classes of CPU architecture can be define:
* - little endian
* - big endian
*
* They describe the way the processor store multi-byte values
* in memory. Considering an 32 bits integer value encoded in
* hexadecimal `0x11223344`. This value needs four bytes to be
* stored. These for bytes will have consecutive addresses in memory.
* Let says that these addresses will be : 01, 02, 03, and 04
*
* ###A big endian architecture will store our integer with the following schema:
*
* Address | 01 | 02 | 03 | 04
* ---------|------|------|------|------
* value | Ox11 | Ox22 | 0x33 | 0x44
*
* In this architecture the last address (the end of the representation) is
* used to store the byte of higher weight (BIG ENDian)
*
* ###A little endian architecture will store our integer with the following schema:
*
* Address | 01 | 02 | 03 | 04
* ---------|------|------|------|------
* value | Ox44 | Ox33 | 0x22 | 0x11
*
* In this architecture the last address is
* used to store the byte of lighter weight (LITTLE ENDian)
*
* @return a `bool` value:
* - `true` if the architecture is little endian
* - `false` if the architecture is big endian
*
* @author Eric Coissac (coissac)
* @created on 23/05/2015
*/
bool islittlend();
#endif /* LITTLEBIGMAN_H_ */
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment