• In computing, an opcode (abbreviated from operation code) is an enumerated value that specifies the operation to be performed. Opcodes are employed in...
    17 KB (1,169 words) - 18:27, 18 March 2025
  • An opcode table (also called an opcode matrix) is a visual representation of all opcodes in an instruction set. It is arranged such that each axis of...
    9 KB (213 words) - 22:08, 27 February 2025
  • Thumbnail for Machine code
    assembly, numerical opcodes and operands are replaced with mnemonics and labels. For example, the x86 architecture has available the 0x90 opcode; it is represented...
    34 KB (3,551 words) - 09:25, 30 May 2025
  • Opcode Systems, Inc. was founded in 1985 by Dave Oppenheim and based in and around Palo Alto, California, USA. Opcode produced MIDI sequencing software...
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  • Thumbnail for Illegal opcode
    An illegal opcode, also called an unimplemented operation, unintended opcode or undocumented instruction, is an instruction to a CPU that is not mentioned...
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  • PREFETCHW, opcode 0F 0D /0 as well as opcodes 0F 0D /2../7 are all documented to be performing prefetch. On Intel processors with PREFETCHW, these opcodes are...
    263 KB (14,911 words) - 15:01, 7 May 2025
  • Thumbnail for Assembly language
    uses a mnemonic to represent, e.g., each low-level machine instruction or opcode, each directive, typically also each architectural register, flag, etc....
    89 KB (9,905 words) - 08:03, 13 June 2025
  • SIGTRAP. The opcode for INT3 is 0xCC, as opposed to the opcode for INT immediate8, which is 0xCD immediate8. Since the dedicated 0xCC opcode has some desired...
    4 KB (472 words) - 17:32, 29 November 2024
  • The Intel BCD opcodes are a set of six x86 instructions that operate with binary-coded decimal numbers. The radix used for the representation of numbers...
    10 KB (1,363 words) - 23:07, 6 March 2025
  • instructions. On the processing architecture, a given instruction may specify: opcode (the instruction to be performed) e.g. add, copy, test any explicit operands:...
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  • Fetching the instruction opcodes from program memory well in advance is known as prefetching and it is served by using a prefetch input queue (PIQ). The...
    12 KB (1,695 words) - 22:00, 30 July 2023
  • Thumbnail for Instruction cycle
    operations based on specific opcodes in the instruction. For example, in RISC-V architecture, funct3 and funct7 opcodes exist to distinguish whether an...
    10 KB (1,255 words) - 07:48, 24 April 2025
  • Thumbnail for Intel MCS-51
    initial opcode byte, followed by up to 2 bytes of operands. 1⁄4 of the opcode bytes, x0–x3, are used for irregular opcodes. 3⁄4 of the opcode bytes, x4–xF...
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  • Thumbnail for Computer
    code or opcode for short). The command to add two numbers together would have one opcode; the command to multiply them would have a different opcode, and...
    140 KB (14,125 words) - 23:29, 1 June 2025
  • Thumbnail for Arithmetic logic unit
    called operands, and a code indicating the operation to be performed (opcode); the ALU's output is the result of the performed operation. In many designs...
    27 KB (3,326 words) - 15:57, 30 May 2025
  • Thumbnail for WebSocket
    WebSocket (section Opcodes)
    and opcode ≠ 0. A fragmented message consists of one frame with FIN = 0 and opcode ≠ 0, followed by zero or more frames with FIN = 0 and opcode = 0,...
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  • design flaw was discovered by programmers. Due to incomplete opcode decoding, two illegal opcodes, 0x9D and 0xDD, will cause the program counter on the processor...
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  • Thumbnail for CHIP-8
    CHIP-8 (section Opcode table)
    the semantics of a few of the opcodes, and SCHIP continued to use those new semantics in addition to changing other opcodes. Many online resources about...
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  • is the same on all Art-Net packets; the green portion is variable. The opcode (given in little endian) tells the recipient this is a packet containing...
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  • to: STOS BASIC, a programming language for the Atari ST computer stos, an opcode mnemonic in X86 assembly language Secure Trusted Operating System Consortium...
    420 bytes (90 words) - 10:21, 18 October 2017
  • effects; for example, on the Motorola 68000 series of processors, the NOP opcode causes a synchronization of the pipeline. Listed below are the NOP instruction...
    38 KB (2,388 words) - 21:38, 8 June 2025
  • some variety in the lengths of opcodes that can be used for this purpose; good shellcode writers can put these small opcodes to use to create more compact...
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  • version 2. This version featured 16-bit opcodes and numerous changes which enhanced its utility. PICT 1 opcodes were supported as a subset for backward...
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  • Metasploit (redirect from Opcode Database)
    against a remote target machine. Other important sub-projects include the Opcode Database, shellcode archive and related research. The Metasploit Project...
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  • assigned by the program that generates any kind of query. QR - Query/Response. OPCODE - A 4-bit field that specifies the kind of query in this message. This value...
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  • Thumbnail for TI-990
    of program SVC DATA >0000 R3 - Open I/O opcode DATA >0B00 R4 - Write I/O opcode DATA >0100 R5 - Close I/O opcode DATA STRING R6 - Message address DATA STRLEN...
    21 KB (2,990 words) - 08:06, 2 April 2025
  • Thumbnail for Zilog Z80
    registers. The binary opcodes (machine language) were identical, but preceded by a new opcode prefix. Zilog published the opcodes and related mnemonics...
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  • Thumbnail for Logic analyzer
    timing diagrams, protocol decodes, state machine traces, opcodes, or may correlate opcodes with source-level software. Logic analyzers have advanced...
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  • Thumbnail for DEC Alpha
    It has a 6-bit opcode field, a 5-bit Ra field, a 5-bit Rb field and a 16-bit displacement field. Branch instructions have a 6-bit opcode field, a 5-bit...
    63 KB (6,361 words) - 18:54, 23 May 2025
  • Thumbnail for MOS Technology 6502
    instruction operation codes (opcodes) are 8 bits long and have the general form AAABBBCC, where AAA and CC define the opcode, and BBB defines the addressing...
    118 KB (11,764 words) - 02:32, 12 June 2025