Endianness

Endianness is the order or sequence of bytes. It is primarily expressed as big-endian (BE) or little-endian (LE). As an example, let's look at the 32-bit integer 0x75BCD15:

graph LR
    input[0x075BCD15]
    input -- most significant --> A1[0x07] --> output
    input --> B1[0x5B] --> output
    input --> C1[0xCD] --> output
    input -- least significant --> D1[0x15] --> output
    output[123456789]

The 32-bit integer 0x075BCD15 has the value 123456789 on a big-endian system.

graph LR
    input[0x075BCD15]
    input -- least significant --> A1[0x15] --> output
    input --> B1[0xCD] --> output
    input --> C1[0x5B] --> output
    input -- most significant --> D1[0x07] --> output
    output[365779719]

The 32-bit integer 0x075BCD15 has the value 365779719 on a little-endian system.

Game Version Differences

• Skyrim Legendary Edition: big-endian
• Skyrim Special Edition: big-endian
• Fallout 4: little-endian

The differences between the versions can be explained by looking at the target platforms:

• PlayStation 3: big-endian
• Xbox 360: big-endian
• PlayStation 4: (AMD64 x86-64) little-endian
• Xbox One: (AMD64 x86-64) little-endian
• PlayStation 5: (AMD64 x86_64) little-endian
• Xbox Series X/S: (AMD64 x86_64) little-endian

Aside from the PS3 and Xbox 360, all current platforms use the x86-64 architecture and little-endian. They likely didn't change the endianness of Skyrim Special Edition scripts to keep compatibility with Skyrim Legendary Edition scripts.