The order in which the most significant byte of a multibyte value comes first is called Big-Endian and it's used in some of file formats, network protocols or as the native way of keeping numbers in memory on some hardware platforms (like Xbox 360). So it would be natural and intuitive to think that compuler stores such 32-bit number as such consecutive four bytes (shown as hex numbers) : 01 32 B4 EB (Big-Endian)īut it's often not the case. In all notations we as humans and programmers use to show numbers, whether it has decimal, hexadecimal, octal or binary radix, we start from the most significant digit. Let's say we have a 32-bit unsigned integer number: 20100331 = 0x0132B4EB
But as a number spans across multiple bytes, things get a little more complicated. As byte is the smallest piece of data that can be addressed and processed, we don't care in what order does the memory or file store the bits inside of it. I wish the creators of C++ allowed this instead of totally unuseful and misleading octal numbers starting with just 0 :(īack to the point.
So for example, if we have an 8-bit unsigned integer number, we could write it this way: 201 = 0b11001001īTW, new the Java version 7 will have the ability to understand such binary numbers starting with 0b. As we all know, a byte has 8 bits and we usually imagine it as a sequence of zeros and ones ordered from the most signififant bit to the least significant bit. It is (or at least should be) always clearly stated which endianess is in use in particular hardware platform, file format or network protocol.īut let's start with something simple. There are two possibilites: Big-Endian and Little-Endian. It's simply the way of storing numbers that span across many bytes in the computer memory, file or network.
I keep it for reference, but it probably doesn't reflect my current knowledge and beliefs.įor those of my readers who don't know this subject yet, here is my brief introduction to what the endianess is. Warning! Some information on this page is older than 6 years now.
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