Byte Order and Byte Swapping

Include File(s): SDL_endian.h

Introduction

This category contains functions for reading and writing endian-specific values.

Endianness comes in two forms - big and little.

• SDL_LIL_ENDIAN means byte order is 1234, where the smaller (little) numbered position comes first
• SDL_BIG_ENDIAN means byte order is 4321, where the larger (big) numbered position comes first

• Example:

  • D E A D B E E F   (a stored value)
    |_|
    8 bits = 1 byte
    |_| |_| |_| |_|
     1   2   3   4  (4 bytes; A = lowest address)
    |_____________|
        32 bits
    
    Imagine the hexadecimal sequence in byte form of DE AD BE EF
    
    When the value is read out of memory as a little-endian value it will produce:
    EFBEADDE
    When the value is read out of memory as a big-endian value it will produce:
    DEADBEEF

SDL_byte_order corresponds to the byte order used by the processor type it was compiled for.

• SDL byte order is SDL_LIL_ENDIAN for x86, x64, and similar systems that use the little endian byte order.
• SDL byte order is SDL_BIG_ENDIAN for PowerPC Mac and similar systems that use the big endian byte order.

Functions

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