machine code


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Related to machine code: machine language, Assembly code

machine code

, language
instructions for the processing of data in a binary, octal, or hexadecimal code that can be understood and executed by a computer

machine code

[mə′shēn ‚kōd]
(computer science)
A computer representation of a character, digit, or action command in internal form.
A computer instruction in internal format, or that part of the instruction which identifies the action to be performed.
The set of all instruction types that a particular computer can execute.

machine code

The representation of a computer program which is actually read and interpreted by the computer. A program in machine code consists of a sequence of machine instructions (possibly interspersed with data). Instructions are binary strings which may be either all the same size (e.g. one 32-bit word for many modern RISC microprocessors) or of different sizes, in which case the size of the instruction is determined from the first word (e.g. Motorola 68000) or byte (e.g. Inmos transputer). The collection of all possible instructions for a particular computer is known as its "instruction set".

Execution of machine code may either be hard-wired into the central processing unit or it may be controlled by microcode. The basic execution cycle consists of fetching the next instruction from main memory, decoding it (determining which operation it specifies and the location of any arguments) and executing it by opening various gates (e.g. to allow data to flow from main memory into a CPU register) and enabling functional units (e.g. signalling to the ALU to perform an addition).

Humans almost never write programs directly in machine code. Instead, they use a programming language which is translated by the computer into machine code. The simplest kind of programming language is assembly language which usually has a one-to-one correspondence with the resulting machine code instructions but allows the use of mnemonics (ASCII strings) for the "op codes" (the part of the instruction which encodes the basic type of operation to perform) and names for locations in the program (branch labels) and for variables and constants.

machine code

The binary instructions a CPU executes. See machine language.
References in periodicals archive ?
We do not address such exploitation scenarios due to the lack of real valid machine code in the attacking traffic.
If the verification succeeds, the Java Bytecode is interpreted or executed directly after JIT compilation into machine code from the Java Bytecode.
A handy side effect is that I can't look inside a program on my computer (such as Microsoft Word) and see how it works: All I'd see is machine code, effectively gibberish.
Another technique to execute Java programs is with a compiler that translates the Java bytecodes into native machine code.
Next, while working on 1400 series IBM equipment, I was introduced to the wonderful option of including machine code patch decks at the end of run decks, usually a quick and dirty fix that sometimes never became a correction to the source code.
Machine code released under approved foreign military sales was vulnerable to assembly-level reverse engineering.
Also included is a machine code which identifies the specific production machine and the particular process-related data associated with the manufacture of that individual part.
Above that, we can abstract machine code to assembly code.
By contrast, data manipulation entails taking working programs, freezing them, and then rewriting a system's lines - often millions - of machine code.
Any user-oriented computer language is merely a tool to obscure the real action going on at machine code level.
District Court has ruled that (1) only workloads expressly authorized by IBM may be processed on Specialty Engines (including zIIPs and zAAPs) and (2) IBM's contracts, including the IBM Customer Agreement and the License Agreement for Machine Code, prohibit software (a) that enables workloads not expressly authorized by IBM to be processed on Specialty Engines or (b) that circumvents IBM's technological measures in Machine Code that protect the Built-in Capacity of Specialty Engines and enables workloads not expressly authorized by IBM to be processed on Specialty Engines.
Once compiled the intermittent JVM or Java Virtual Machine takes compiled byte code and converts it into machine code which is understood by the machine.