little-endian
Endian formats refer to the order in which bytes are arranged within larger data types, such as integers or floating-point numbers, in computer memory. There are two main types: big-endian, where the most significant byte is stored first, and little-endian, where the least significant byte is stored first. The choice of endian format can affect data interpretation, especially in systems that communicate with each other using different byte orders. Understanding endian formats is crucial in programming, networking, and data serialization.
"Little Endian" means that the lower-order byte of the number is stored in memory at the lowest address, and the high-order byte at the highest address. For example, a 4 byte Integer Byte3 Byte2 Byte1 Byte0 will be arranged in memory as follows: Base Address+0 Byte0 Base Address+1 Byte1 Base Address+2 Byte2 Base Address+3 Byte3 Intel processors (those used in PC's) use "Little Endian" byte order. "Big Endian" means that the high-order byte of the number is stored in memory at the lowest address, and the low-order byte at the highest address. The same 4 byte integer would be stored as: Base Address+0 Byte3 Base Address+1 Byte2 Base Address+2 Byte1 Base Address+3 Byte0 Motorola processors (those used in Mac's) use "Big Endian" byte order.
The terms big-endian/little-endian come from Jonathan Swift's Gulliver's Travels. In Lilliput, a royal edict required its citizens to open soft boiled eggs from the small end. In the rival kingdom of Blefuscu, they opened them from the big end, earning them the name Big-endians. In computing, the terms are intended to indicate from which end a multi-byte numeric value is written. With little-endian, the least-significant byte always comes first (thus the value is written in reverse). This makes it much easier to cast from one type to another. For instance, a wide character consumes two bytes (a word). For characters within the ASCII character set, the first byte is always 0x00 while the second byte stores the actual ASCII character code (0x00 to 0xFF). With big-endian notation, casting a wide character to an ASCII character results in the ASCII character always having the value 0x00 because that is the first byte. In little-endian, the bytes are reversed thus the first byte is the ASCII character code.
There are n no. of ways for determining endianness of your machine. Here is one quick way of doing the same.#include <stdio.h> int main() { unsigned int i = 1; char *c = (char*)&i; if (*c) printf("Little endian"); else printf("Big endian"); getchar(); return 0; } In the above program, a character pointer c is pointing to an integer i. Since size of character is 1 byte when the character pointer is de-referenced it will contain only first byte of integer. If machine is little endian then *c will be 1 (because last byte is stored first) and if machine is big endian then *c will be 0.
It depends how you want to encode it. Encoding as 8-bit ASCII (ISO/IEC/8859 or ISO-8859-1) it will be: 0x6920616d20736576656e00 Note the 0x00 at the end is the null terminator. Total length is 11 bytes. However, you will probably want to replace the lowercase 'i' with an uppercase 'I' (in all version of English, the singular first person noun 'I' is always capitalised), in which case the encoding would be: 0x4920616d20736576656e00 Encoding as 16-bit UNICODE is the same except each byte is padded with 8 zero bits (0x00) and a BOM (byte-order mark) is inserted at the front to ensure correct interpretation. In big-endian notation, the binary value would be: 0xfeff004900200061006d00200073006500760065006e0000 In little-endian notation, it would be: 0xfffe4900200061006d00200073006500760065006e000000 Similarly with 32-bit UNICODE, padding with another 16 zero bits along with a 32-bit BOM: 32-bit big-endian: 0x0000feff0000004900000020000000610000006d00000020000000730000006500000076000000650000006e00000000 32-bit little-endian: 0xfffe0000004900000020000000610000006d00000020000000730000006500000076000000650000006e000000000000 There are many other ways to encode text. This is primarily due to the wide variety of character sets available to cater for foreign languages and other symbols. It is also possible to use compression encodings, cipher encodings and encrypted encodings. But in order to interpret these encodings correctly you would need to know precisely how it was encoded, in the same way a BOM tells the decoder how to correctly interpret the byte order.
Both little and big endian are still in use today. In big endian the most significant byte is the smallest address stored. In little endian the least significant byte is the smallest address stored.
In a 32-bit word, the decimal value 3 has hex value 0x00000003. Laid out in memory in a little-endian computer, it is 0x03, 0x00, 0x00, 0x00. If you move that to a big-endian computer without reversing the byte order, you get 0x03000000, which is decimal 50,331,648. The correct big-endian representation should have been 0x00, 0x00, 0x00, 0x03.
Big endian does not change the ordering, so it is stored as 0x1234
24.6391 is represented in IEEE real*4 (32-bit real number) as: 0x41c51ce0 (big-endian) 0xe01cc541 (little-endian)
Endianness relates to the order of bytes in a multi-byte value. Humans prefer to work with big-endian notation, such that the value 123 is interpreted as being one-hundred-and-twenty-three. In little-endian notion, 123 would be interpreted as being three-hundred-and-twenty-one. In other words, the significance of the digit positions is completely reversed. With big-endian notation, the most significant digit always comes first. With little-endian notation, the least-significant digit comes first.Note that although the word 'end' usually means final or last, the term derives from Jonathan Swift's novel, Gulliver's Travels, where a civil war breaks out over which end of a soft-boiled egg to crack first; the big end or the little end, analogous to the most-significant or least-significant end of a multi-digit value respectively.
Endian formats refer to the order in which bytes are arranged within larger data types, such as integers or floating-point numbers, in computer memory. There are two main types: big-endian, where the most significant byte is stored first, and little-endian, where the least significant byte is stored first. The choice of endian format can affect data interpretation, especially in systems that communicate with each other using different byte orders. Understanding endian formats is crucial in programming, networking, and data serialization.
Big-endian byte ordering in Motorola microprocessors is significant because it determines the way data is stored in memory. In big-endian systems, the most significant byte of a multi-byte data is stored at the lowest memory address, which can impact data manipulation and communication with other systems.
The "Big Endian" and "Small Endian" philosophies described by Jonathan Swift in "Gulliver's Travels".
"Little Endian" means that the lower-order byte of the number is stored in memory at the lowest address, and the high-order byte at the highest address. For example, a 4 byte Integer Byte3 Byte2 Byte1 Byte0 will be arranged in memory as follows: Base Address+0 Byte0 Base Address+1 Byte1 Base Address+2 Byte2 Base Address+3 Byte3 Intel processors (those used in PC's) use "Little Endian" byte order. "Big Endian" means that the high-order byte of the number is stored in memory at the lowest address, and the low-order byte at the highest address. The same 4 byte integer would be stored as: Base Address+0 Byte3 Base Address+1 Byte2 Base Address+2 Byte1 Base Address+3 Byte0 Motorola processors (those used in Mac's) use "Big Endian" byte order.
The terms big-endian/little-endian come from Jonathan Swift's Gulliver's Travels. In Lilliput, a royal edict required its citizens to open soft boiled eggs from the small end. In the rival kingdom of Blefuscu, they opened them from the big end, earning them the name Big-endians. In computing, the terms are intended to indicate from which end a multi-byte numeric value is written. With little-endian, the least-significant byte always comes first (thus the value is written in reverse). This makes it much easier to cast from one type to another. For instance, a wide character consumes two bytes (a word). For characters within the ASCII character set, the first byte is always 0x00 while the second byte stores the actual ASCII character code (0x00 to 0xFF). With big-endian notation, casting a wide character to an ASCII character results in the ASCII character always having the value 0x00 because that is the first byte. In little-endian, the bytes are reversed thus the first byte is the ASCII character code.
There are n no. of ways for determining endianness of your machine. Here is one quick way of doing the same.#include <stdio.h> int main() { unsigned int i = 1; char *c = (char*)&i; if (*c) printf("Little endian"); else printf("Big endian"); getchar(); return 0; } In the above program, a character pointer c is pointing to an integer i. Since size of character is 1 byte when the character pointer is de-referenced it will contain only first byte of integer. If machine is little endian then *c will be 1 (because last byte is stored first) and if machine is big endian then *c will be 0.
There are several "main" differences, that are important, depending on what context you are interested in them for. PowerPC processors are primarily manufactured by IBM and Freescale. Pentium processors are manufactured by Intel. PowerPC processors can operate in both little-endian and big-endian modes. Pentium processors (and compatibles) are little-endian only. PowerPC processors are used in some servers, game consoles, and in embedded kiosks. They were also used in Macs before 2005. Pentium (and compatible) processors are used in most desktop computers, the original Xbox, servers, and some embedded kiosks.