Due to inherently compact and semantically rich instructions, the average amount of work performed per machine code unit ( i. e. per byte or bit ) is higher for a CISC than a RISC processor, which may give it a significant advantage in a modern cache based implementation.

As with many other 8-bit processors, all instructions were encoded in a single byte ( including register-numbers, but excluding immediate data ), for simplicity.

Some aspects of the instruction set are unique, most notably the " byte " instructions, which operated on bit fields of any size from 1 to 36 bits inclusive according to the general definition of a byte as a contiguous sequence of a fixed number of bits.

The PDP-10 assembly language instructions LDB and DPB ( load / deposit byte ) live on as functions in the programming language Common Lisp.

The addressing modes provided register, immediate, absolute, relative, deferred ( indirect ), and indexed addressing, and could specify autoincrementation and autodecrementation of a register by one ( byte instructions ) or two ( word instructions ).

* Few data types in hardware, some CISCs have byte string instructions, or support complex numbers ; this is so far unlikely to be found on a RISC.

* An enhanced instruction set including bit manipulation, block move, block I / O, and byte search instructions

The 64-bit SPARC V9 architecture uses big-endian instructions, but can access data in either big-endian or little-endian byte order, chosen either at the application instruction ( load / store ) level or at the memory page level ( via an MMU setting ).

In other architectures, instructions have variable length, typically integral multiples of a byte or a halfword.

CDC used the term " byte " to refer to 12-bit entities used by peripheral processors ; characters were 6-bit, and central processor instructions were either 15 bits, or 30 bits with a signed 18-bit address field, the latter allowing for a directly addressable memory space of 128K words of central memory ( converted to modern terms, with 8-bit bytes, this is 0. 94 MB ).

With no byte addressing instructions at all, code had to be written to pack and shift characters into words.

Some instructions are single byte / cycle ones, but a large amount of opcodes need two cycles and / or two bytes, so the raw performance would be closer to 0. 5 MIPS.

As in many other 8-bit processors, all instructions are encoded in a single byte ( including register-numbers, but excluding immediate data ), for simplicity.

* Storage defined in terms of bits, when bytes would suffice, may inadvertently involve extremely long path lengths involving bitwise operations instead of more efficient single instruction ' multiple byte ' copy instructions.

For example no fewer than 10 subleq2 instructions are required to flip all the bits in a given byte:

This makes them unsuitable for use in patching instructions ( which can be one byte long ).

The instruction set also used bit-aligned variable-length instructions ( as opposed to the byte or word-aligned semi-fixed formats used in the majority of computer designs ).

Branches, load immediates, and load / store instructions require an argument field, but stack machines often arrange that the frequent cases of these still fit together with thin opcode into a single byte or syllable.

Zilog added a memory management unit ( MMU ) to expand the addressing range to 16 MB, features for multitasking and multiprocessor and coprocessor configurations, a 256 byte cache, and a huge number of new instructions and addressing modes ( giving a total of over 2000 combinations ).

The most important function was known as the byte jumper, a way to step partially through programming instructions and edit them in ways that were not otherwise allowed.

Transferring the contents of one register to another involves four instructions ( one Get and one Put on the HI byte of the register, and a similar pair for the LO byte: GHI R1 ; PHI R2 ; GLO R1 ; PLO R2 ).

For a 256-bit block, the first row is unchanged and the shifting for the second, third and fourth row is 1 byte, 3 bytes and 4 bytes respectively — this change only applies for the Rijndael cipher when used with a 256-bit block, as AES does not use 256-bit blocks.

Based on a newer, slightly more flexible, version of the Asters original Motorola MC6845 video chip, the Rockwell 6545, it worked by adding a new video mode, one with the ability to reprogram an extended, ( 2048 characters instead of 256 characters ) version of the character set, supported by an extended character memory of the video card that did not use one ( 8 bit ) byte per character, but an 11 bit " word ", so it could address each one of the available 2048 unique programmable characters.

Without such precautions, most programs may compile only on a certain platform or with a particular compiler, due, for example, to the use of non-standard libraries, such as GUI libraries, or to the reliance on compiler-or platform-specific attributes such as the exact size of certain data types and byte endianness.

Common Lisp implementations may use any mix of native code compilation, byte code compilation or interpretation.

" Brooks responded " The most important single decision I ever made was to change the IBM 360 series from a 6-bit byte to an 8-bit byte, thereby enabling the use of lowercase letters.

In theory, only a single additional bit is required to tell the decoder that the normal coding has been turned off for the entire input ; however, most encoding algorithms use at least one full byte ( and typically more than one ) for this purpose.

However, one of the main concepts of the MMX instruction set is the concept of packed data types, which means instead of using the whole register for a single 64-bit integer ( quadword ), one may use it to contain two 32-bit integers ( doubleword ), four 16-bit integers ( word ) or eight 8-bit integers ( byte ).

enables the receiver to use the TRC to detect which byte the error occurred in, and the LRC to detect exactly which track the error occurred in, to discover exactly which bit is in error, and then correct that bit by flipping it.

Many protocols use such an XOR-based longitudinal redundancy check byte,

Ways to get around this problem include re-synchronization of the clocks and use of check digits to ensure the byte is correctly interpreted and received

Functions are sometimes needed for computers of different endianness to communicate with each other over the internet, as protocols often use big endian byte coding by default.

Like the File Record, the Directory Record also stores two 16 byte fields for use by the Finder.

They specifically mention the use of ASCII character set " transmitted as a 8-bit byte with the high-order bit cleared to zero " and some of these

All traditional AIFF and AIFF-C files continue to work normally on Mac OS X ( including on the new Intel-based hardware ), and many third-party audio applications as well as hardware continue to use the standard AIFF big-endian byte order.

POSIX defines " character " as a sequence of one or more bytes representing a single graphic symbol or control code, and attempts to use " byte " when referring to char data ..

Instead they use " control-octet transparency ", also called " byte stuffing " or " octet stuffing ".

However, through the use of 2 color palettes and a left / right boundary control byte you could have the left section of screen ( this could be the play field ) use 1 set of colors while the right side ( this could show information such as lives and score ) used an entirely different set of colors, thus 8 total colors were possible.

The TIFF 6. 0 specification says that compliant TIFF readers must support both byte orders ( II and MM ); writers may use either.

The number of characters needed in order to write English is very small, and thus it is possible to use only one byte to encode one English character.

To move the higher byte of the 16-bit register BX sign-extended into the 32-bit register EAX, use:

Numerically odd values may be preferred so that processors without byte addressing will fault when attempting to use them as pointers ( which must fall at even addresses ).