• 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) - 22:24, 15 July 2025
  • Thumbnail for Machine code
    machine code opcodes and operands are replaced with mnemonics and labels. For example, the x86 architecture has available the 0x90 opcode; it is represented...
    38 KB (3,880 words) - 10:47, 24 July 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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  • 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...
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  • 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 (9,898 words) - 15:05, 16 July 2025
  • 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...
    265 KB (15,000 words) - 22:03, 26 July 2025
  • computing, an opcode prefix is an numeric value that alters the function of a following opcode. On some instruction set architectures multiple opcode prefixes...
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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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  • 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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  • 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 (478 words) - 16:42, 24 July 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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  • 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...
    17 KB (1,623 words) - 19:04, 20 July 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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  • 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...
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  • 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
  • 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 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...
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  • 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) - 20:14, 20 June 2025
  • 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 (14,116 words) - 21:09, 25 July 2025
  • 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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  • 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
  • (immediate), and J (jump). Every instruction starts with a 6-bit opcode. In addition to the opcode, R-type instructions specify three registers, a shift amount...
    70 KB (8,083 words) - 19:26, 27 July 2025
  • 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...
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  • performed by these opcodes is the same for Intel and AMD. This documentation difference applies only to the MMX/SSE forms of these opcodes — for VEX/EVEX-encoded...
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  • 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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  • machine implemented as an opcodes interpreter which runs previously compiled programs written in the Perl language. The opcodes interpreter is a part of...
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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...
    4 KB (406 words) - 07:07, 22 February 2024
  • 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 Reduced instruction set computer
    conclusions worked in concert; removing instructions would allow the instruction opcodes to be shorter, freeing up bits in the instruction word which could then...
    62 KB (7,270 words) - 23:22, 6 July 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 (11,835 words) - 13:51, 17 July 2025