Most significant bit

In computing, the most significant bit (msb, also called the high-order bit) is the bit position in a binary number having the greatest value. The msb is sometimes referred to as the left-most bit due to the convention in positional notation of writing more significant digits further to the left.

The msb can also correspond to the sign of a signed binary number in one or two's complement notation. "1" meaning negative and "0" meaning positive.

It is common to assign each bit a position number, ranging from zero to N-1, where N is the number of bits in the binary representation used. Normally, this is simply the exponent for the corresponding bit weight in base-2 (such as in 231..20). Although a few CPU manufacturers assign bit numbers the opposite way (which is not the same as different endianness), the msb unambiguously remain the most significant bit. This may be one of the reasons why the term msb is often used instead of a bit number, although the primary reason is probably that different number representations use different numbers of bits.

By extension, the most significant bits (plural) are the bits closest to, and including, the msb.

The unsigned binary representation of decimal 149, with the msb highlighted. The msb in an 8-bit binary number represents a value of 128 decimal. The lsb represents a value of 1.

Other uses

MSB, in all capitals, can also stand for "most significant byte". The meaning is parallel to the above: it is the byte (or octet) in that position of a multi-byte number which has the greatest potential value.

See also


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  • Most Significant Bit — Bit de poids fort Le bit de poids fort, (en anglais Most Significant Bit, ou MSB) est le bit, dans une représentation binaire donnée, ayant la plus grande valeur (celui de gauche dans la représentation positionnelle habituelle). Exemple: le… …   Wikipédia en Français

  • Most Significant Bit —   [dt. »höchstwertiges Bit«], Wertigkeit …   Universal-Lexikon

  • Most Significant Bit — Die Bitwertigkeit bezeichnet den Stellenwert eines einzelnen Bits, den es durch seine Position innerhalb einer Binärzahl (meist Dualzahl) hat. Inhaltsverzeichnis 1 MSB 2 LSB 3 Byte Reihenfolge 4 Zahlenformat und Vorzeichenbit …   Deutsch Wikipedia

  • most significant bit — noun The bit that represents the largest fraction of a value, its position depending on the endianness of the system. Syn: MSB Ant: least significant bit …   Wiktionary

  • most significant bit — noun Computing the bit in a binary number which is of the greatest numerical value …   English new terms dictionary

  • most significant bit — …   Useful english dictionary

  • Least significant bit — In computing, the least significant bit (lsb) is the bit position in a binary integer giving the units value, that is, determining whether the number is even or odd. The lsb is sometimes referred to as the right most bit, due to the convention in …   Wikipedia

  • Least Significant Bit — Die Bitwertigkeit bezeichnet den Stellenwert eines einzelnen Bits, den es durch seine Position innerhalb einer Binärzahl (meist Dualzahl) hat. Inhaltsverzeichnis 1 MSB 2 LSB 3 Byte Reihenfolge 4 Zahlenformat und Vorzeichenbit …   Deutsch Wikipedia

  • least significant bit — noun The bit that represents the smallest fraction of a value, its position depending on the endianness of the system. Syn: LSB Ant: most significant bit …   Wiktionary

  • Bit más significativo — Saltar a navegación, búsqueda En electrónica digital, el bit más significativo, most significant bit (msb), en sus siglas en inglés, es el bit, que de acuerdo a su posición, tiene el mayor valor. En ocasiones, se hace referencia al msb como el… …   Wikipedia Español


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