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Low-level Programming Languages
A low-level programming language is a programming language that provides little or no abstraction from a computer's instruction set architecture, memory or underlying physical hardware; commands or functions in the language are structurally similar to a processor's instructions. These languages provide the programmer with full control over program memory and the underlying machine code instructions. Because of the low level of abstraction (hence the term "low-level") between the language and machine language, low-level languages are sometimes described as being "close to the hardware". Programs written in low-level languages tend to be relatively non-portable, due to being optimized for a certain type of system architecture. Low-level languages are directly converted to machine code with or without a compiler or interpreter— second-generation programming languages depending on programming language. A program written in a low-level language can be made to run very quickly, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programming Language
A programming language is a system of notation for writing computer programs. Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually defined by a formal language. Languages usually provide features such as a type system, Variable (computer science), variables, and mechanisms for Exception handling (programming), error handling. An Programming language implementation, implementation of a programming language is required in order to Execution (computing), execute programs, namely an Interpreter (computing), interpreter or a compiler. An interpreter directly executes the source code, while a compiler produces an executable program. Computer architecture has strongly influenced the design of programming languages, with the most common type (imperative languages—which implement operations in a specified order) developed to perform well on the popular von Neumann architecture. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semantics (computer Science)
In programming language theory, semantics is the rigorous mathematical study of the meaning of programming languages. Semantics assigns computational meaning to valid strings in a programming language syntax. It is closely related to, and often crosses over with, the semantics of mathematical proofs. Semantics describes the processes a computer follows when executing a program in that specific language. This can be done by describing the relationship between the input and output of a program, or giving an explanation of how the program will be executed on a certain platform, thereby creating a model of computation. History In 1967, Robert W. Floyd published the paper ''Assigning meanings to programs''; his chief aim was "a rigorous standard for proofs about computer programs, including proofs of correctness, equivalence, and termination". Floyd further wrote: A semantic definition of a programming language, in our approach, is founded on a syntactic definition. It mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stack-based Memory Allocation
Stacks in computing architectures are regions of memory where data is added or removed in a last-in-first-out (LIFO) manner. In most modern computer systems, each thread has a reserved region of memory referred to as its stack. When a function executes, it may add some of its local state data to the top of the stack; when the function exits it is responsible for removing that data from the stack. At a minimum, a thread's stack is used to store the location of a return address provided by the caller in order to allow return statements to return to the correct location. The stack is often used to store variables of fixed length local to the currently active functions. Programmers may further choose to explicitly use the stack to store local data of variable length. If a region of memory lies on the thread's stack, that memory is said to have been allocated on the stack, i.e. stack-based memory allocation (SBMA). This is contrasted with a heap-based memory allocation (HBMA) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X86 Calling Conventions
This article describes the calling conventions used when programming x86 architecture microprocessors. Calling conventions describe the interface of called code: *The order in which atomic (scalar) parameters, or individual parts of a complex parameter, are allocated *How parameters are passed (pushed on the stack, placed in registers, or a mix of both) *Which registers the called function must preserve for the caller (also known as: callee-saved registers or non-volatile registers) *How the task of preparing the stack for, and restoring after, a function call is divided between the caller and the callee This is intimately related with the assignment of sizes and formats to programming-language types. Another closely related topic is name mangling, which determines how symbol names in the code are mapped to symbol names used by the linker. Calling conventions, type representations, and name mangling are all part of what is known as an application binary interface (ABI). There a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Processor Register
A processor register is a quickly accessible location available to a computer's processor. Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-only. In computer architecture, registers are typically addressed by mechanisms other than main memory, but may in some cases be assigned a memory address e.g. DEC PDP-10, ICT 1900. Almost all computers, whether load/store architecture or not, load items of data from a larger memory into registers where they are used for arithmetic operations, bitwise operations, and other operations, and are manipulated or tested by machine instructions. Manipulated items are then often stored back to main memory, either by the same instruction or by a subsequent one. Modern processors use either static or dynamic random-access memory (RAM) as main memory, with the latter usually accessed via one or more cache levels. Processor registers are normal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel Syntax
x86 assembly language is a family of low-level programming languages that are used to produce object code for the x86 class of processors. These languages provide backward compatibility with CPUs dating back to the Intel 8008 microprocessor, introduced in April 1972. As assembly languages, they are closely tied to the architecture's machine code instructions, allowing for precise control over hardware. In x86 assembly languages, mnemonics are used to represent fundamental CPU instructions, making the code more human-readable compared to raw machine code. Each mnemonics corresponds to a basic operation performed by the processor, such as arithmetic calculations, data movement, or control flow decisions. Assembly languages are most commonly used in applications where performance and efficiency are critical. This includes real-time embedded systems, operating-system kernels, and device drivers, all of which may require direct manipulation of hardware resources. Additionally, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X86 Assembly Language
x86 assembly language is a family of Low-level programming language, low-level programming languages that are used to produce object code for the x86 class of processors. These languages provide backward compatibility with CPUs dating back to the Intel 8008 microprocessor, introduced in April 1972. As assembly languages, they are closely tied to the architecture's machine code instructions, allowing for precise control over hardware. In x86 assembly languages, mnemonics are used to represent fundamental CPU instructions, making the code more human-readable compared to raw machine code. Each mnemonics corresponds to a basic operation performed by the processor, such as arithmetic calculations, data movement, or Control flow, control flow decisions. Assembly languages are most commonly used in applications where performance and efficiency are critical. This includes Real-time operating system, real-time embedded systems, operating system, operating-system Kernel (operating system) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macro (computer Science)
In computer programming, a macro (short for "macro instruction"; ) is a rule or pattern that specifies how a certain input should be mapped to a replacement output. Applying a macro to an input is known as macro expansion. The input and output may be a sequence of lexical tokens or characters, or a syntax tree. Character macros are supported in software applications to make it easy to invoke common command sequences. Token and tree macros are supported in some programming languages to enable code reuse or to extend the language, sometimes for domain-specific languages. Macros are used to make a sequence of computing instructions available to the programmer as a single program statement, making the programming task less tedious and less error-prone. Thus, they are called "macros" because a "big" block of code can be expanded from a "small" sequence of characters. Macros often allow positional or keyword parameters that dictate what the conditional assembler program gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loader (computing)
In computing, computer systems a loader is the part of an operating system that is responsible for loading computer program, programs and Library (computing), libraries. It is one of the essential stages in the process of starting a program, as it places programs into memory and prepares them for execution. Loading a program involves either memory-mapped file, memory-mapping or copying the contents of the executable, executable file containing the program instructions into memory, and then carrying out other required preparatory tasks to prepare the executable for running. Once loading is complete, the operating system starts the program by passing control to the loaded program code. All operating systems that support program loading have loaders, apart from highly specialized computer systems that only have a fixed set of specialized programs. Embedded systems typically do not have loaders, and instead, the code executes directly from ROM or similar. In order to load the operatin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linker (computing)
A linker or link editor is a computer program that combines intermediate software build files such as object file, object and library (computing), library files into a single executable file such as a program or library. A linker is often part of a toolchain that includes a compiler and/or assembler (computing), assembler that generates intermediate files that the linker processes. The linker may be integrated with other toolchain development tool, tools such that the user does not interact with the linker directly. A simpler version that writes its Input/output, output directly to Computer memory, memory is called the ''loader'', though loader (computing), loading is typically considered a separate process. Overview Computer programs typically are composed of several parts or modules; these parts/modules do not need to be contained within a single object file, and in such cases refer to each other using symbol (computing), symbols as addresses into other modules, which are ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object File
An object file is a file that contains machine code or bytecode, as well as other data and metadata, generated by a compiler or assembler from source code during the compilation or assembly process. The machine code that is generated is known as object code. The object code is usually relocatable, and not usually directly executable. There are various formats for object files, and the same machine code can be packaged in different object file formats. An object file may also work like a shared library. The metadata that object files may include can be used for linking or debugging; it includes information to resolve symbolic cross-references between different modules, relocation information, stack unwinding information, comments, program symbols, and debugging or profiling information. Other metadata may include the date and time of compilation, the compiler name and version, and other identifying information. The term "object program" dates from at least the 1950s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machine Instruction (computing)
In computer programming, machine code is computer code consisting of machine language instructions, which are used to control a computer's central processing unit (CPU). For conventional binary computers, machine code is the binaryOn nonbinary machines it is, e.g., a decimal representation. representation of a computer program that is actually read and interpreted by the computer. A program in machine code consists of a sequence of machine instructions (possibly interspersed with data). Each machine code instruction causes the CPU to perform a specific task. Examples of such tasks include: # Load a word from memory to a CPU register # Execute an arithmetic logic unit (ALU) operation on one or more registers or memory locations # Jump or skip to an instruction that is not the next one In general, each architecture family (e.g., x86, ARM) has its own instruction set architecture (ISA), and hence its own specific machine code language. There are exceptions, such as the VA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
