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Binary File Descriptor Library
The Binary File Descriptor library (BFD) is the GNU Project's main mechanism for the portable manipulation of object files in a variety of formats. , it supports approximately 50 file formats for some 25 instruction set architectures. History When David Henkel-Wallace of Cygnus Support proposed developing the library as a way to open up new business opportunities for the company, Richard Stallman said that it would be difficult; David's response was that it wasn't such a "Big Fucking Deal". Abbreviated to "BFD", this became the library name. "Binary File Descriptor" was invented later as a backronym for "BFD". Design BFD works by presenting a common abstract view of object files. An object file has a "header" with descriptive info; a variable number of "sections" that each has a name, some attributes, and a block of data; a symbol table; relocation entries; and so forth. Internally, BFD translates the data from the abstract view into the details of the bit/byte layout requi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus Solutions
Cygnus Solutions, originally Cygnus Support, was founded in 1989 by John Gilmore, Michael Tiemann and David Henkel-Wallace to provide commercial support for free software. Its tagline was: ''Making free software affordable''. For years, employees of Cygnus Solutions were the maintainers of several key GNU software products, including the GNU Debugger and GNU Binutils (which included the GNU Assembler and Linker). It was also a major contributor to the GCC project and drove the change in the project's management from having a single gatekeeper to having an independent committee. Cygnus developed BFD, and used it to help port GNU to many architectures, in a number of cases working under non-disclosure to produce tools used for initial bringup of software for a new chip design. Cygnus was also the original developer of Cygwin, a POSIX layer and the GNU GNU () is an extensive collection of free software (383 packages as of January 2022), which can be used as an operating sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Little-endian
In computing, endianness, also known as byte sex, is the order or sequence of bytes of a word of digital data in computer memory. Endianness is primarily expressed as big-endian (BE) or little-endian (LE). A big-endian system stores the most significant byte of a word at the smallest memory address and the least significant byte at the largest. A little-endian system, in contrast, stores the least-significant byte at the smallest address. Bi-endianness is a feature supported by numerous computer architectures that feature switchable endianness in data fetches and stores or for instruction fetches. Other orderings are generically called middle-endian or mixed-endian. Endianness may also be used to describe the order in which the bits are transmitted over a communication channel, e.g., big-endian in a communications channel transmits the most significant bits first. Bit-endianness is seldom used in other contexts. Etymology Danny Cohen introduced the terms ''big-endian' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Executable File Formats
In computing, executable code, an executable file, or an executable program, sometimes simply referred to as an executable or binary, causes a computer "to perform indicated tasks according to encoded instructions", as opposed to a data file that must be interpreted (parsed) by a program to be meaningful. The exact interpretation depends upon the use. "Instructions" is traditionally taken to mean machine code instructions for a physical CPU. In some contexts, a file containing scripting instructions (such as bytecode) may also be considered executable. Generation of executable files Executable files can be hand-coded in machine language, although it is far more convenient to develop software as source code in a high-level language that can be easily understood by humans. In some cases, source code might be specified in assembly language instead, which remains human-readable while being closely associated with machine code instructions. The high-level language is compile ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C (programming Language) Libraries
C, or c, is the third letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''cee'' (pronounced ), plural ''cees''. History "C" comes from the same letter as "G". The Semites named it gimel. The sign is possibly adapted from an Egyptian hieroglyph for a staff sling, which may have been the meaning of the name ''gimel''. Another possibility is that it depicted a camel, the Semitic name for which was ''gamal''. Barry B. Powell, a specialist in the history of writing, states "It is hard to imagine how gimel = "camel" can be derived from the picture of a camel (it may show his hump, or his head and neck!)". In the Etruscan language, plosive consonants had no contrastive voicing, so the Greek ' Γ' (Gamma) was adopted into the Etruscan alphabet to represent . Already in the Western Greek alphabet, Gamma first took a '' form in Early Etruscan, then '' in Classical Etru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary Format Description Language
The Binary Format Description (BFD) language is an extension of XSIL which has added conditionals and the ability to reference files by their stream numbers, rather than by their public URLs. A template written in the BFD language can be applied to a binary data file to produce a file with that data formatted with descriptive XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. T ... tags. Such XML-tagged data is then readable by humans and generally by a wider set of computer programs than could read the original data file. External links Binary Format Description (BFD) Language XML-based standards Data modeling languages {{prog-lang-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Core Dump
In computing, a core dump, memory dump, crash dump, storage dump, system dump, or ABEND dump consists of the recorded state of the working memory of a computer program at a specific time, generally when the program has crashed or otherwise terminated abnormally. In practice, other key pieces of program state are usually dumped at the same time, including the processor registers, which may include the program counter and stack pointer, memory management information, and other processor and operating system flags and information. A snapshot dump (or snap dump) is a memory dump requested by the computer operator or by the running program, after which the program is able to continue. Core dumps are often used to assist in diagnosing and debugging errors in computer programs. On many operating systems, a fatal exception in a program automatically triggers a core dump. By extension, the phrase "to dump core" has come to mean in many cases, any fatal error, regardless of whether a recor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embedded System
An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' as part of a complete device often including electrical or electronic hardware and mechanical parts. Because an embedded system typically controls physical operations of the machine that it is embedded within, it often has real-time computing constraints. Embedded systems control many devices in common use today. , it was estimated that ninety-eight percent of all microprocessors manufactured were used in embedded systems. Modern embedded systems are often based on microcontrollers (i.e. microprocessors with integrated memory and peripheral interfaces), but ordinary microprocessors (using external chips for memory and peripheral interface circuits) are also common, especially in more complex systems. In either case, the processor(s) used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNU Debugger
The GNU Debugger (GDB) is a portable debugger that runs on many Unix-like systems and works for many programming languages, including Ada, C, C++, Objective-C, Free Pascal, Fortran, Go, and partially others. History GDB was first written by Richard Stallman in 1986 as part of his GNU system, after his GNU Emacs was "reasonably stable". GDB is free software released under the GNU General Public License (GPL). It was modeled after the DBX debugger, which came with Berkeley Unix distributions. From 1990 to 1993 it was maintained by John Gilmore. Now it is maintained by the GDB Steering Committee which is appointed by the Free Software Foundation. Technical details Features GDB offers extensive facilities for tracing and altering the execution of computer programs. The user can monitor and modify the values of programs' internal variables, and even call functions independently of the program's normal behavior. GDB target processors (as of 2003) include: Alpha, ARM, AVR, H8 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNU Binary Utilities
The GNU Binary Utilities, or , are a set of programming tools for creating and managing binary programs, object files, libraries, profile data, and assembly source code. Tools They were originally written by programmers at Cygnus Solutions. The GNU Binutils are typically used in conjunction with compilers such as the GNU Compiler Collection (), build tools like , and the GNU Debugger (). Through the use of the Binary File Descriptor library (), most tools support the various object file formats supported by . Commands The include the following commands: elfutils Ulrich Drepper wrote , to partially replace GNU Binutils, purely for Linux and with support only for ELF and DWARF. It distributes three libraries with it for programmatic access. See also * GNU Core Utilities * GNU Debugger *ldd (Unix), list symbols imported by the object file; similar to * List of Unix commands *llvm provides similar set of tools * strace strace is a diagnostic, debugging and instructi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNU Linker
In computing, a linker or link editor is a computer system program that takes one or more object files (generated by a compiler or an assembler) and combines them into a single executable file, library file, or another "object" file. A simpler version that writes its output directly to memory is called the ''loader'', though 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 by means of symbols as addresses into other modules, which are mapped into memory addresses when linked for execution. While the process of linking is meant to ultimately combine these independent parts, there are many good reasons to develop those separately at the source-level. Among these reasons are the ease of organizing several smaller pieces over a monolithic whole and the ability to better define the pur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNU Assembler
The GNU Assembler, commonly known as gas or as, is the assembler developed by the GNU Project. It is the default back-end of GCC. It is used to assemble the GNU operating system and the Linux kernel, and various other software. It is a part of the GNU Binutils package. The GAS executable is named , the standard name for a Unix assembler. GAS is cross-platform, and both runs on and assembles for a number of different computer architectures. GAS is free software released under the GNU General Public License v3. History The first version of GAS was released in 1986-1987. It was written by Dean Elsner, and supported the VAX architecture. General syntax GAS supports a general syntax that works for all of the supported architectures. The general syntax includes assembler directives and a method for commenting. The default syntax is AT&T syntax. Directives GAS uses assembler directives (also known as pseudo ops), which are keywords beginning with a period that behave similarly to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Address
In computing, a memory address is a reference to a specific memory location used at various levels by software and hardware. Memory addresses are fixed-length sequences of digits conventionally displayed and manipulated as unsigned integers. Such numerical semantic bases itself upon features of CPU (such as the instruction pointer and incremental address registers), as well upon use of the memory like an array endorsed by various programming languages. Types Physical addresses A digital computer's main memory consists of many memory locations. Each memory location has a physical address which is a code. The CPU (or other device) can use the code to access the corresponding memory location. Generally only system software, i.e. the BIOS, operating systems, and some specialized utility programs (e.g., memory testers), address physical memory using machine code operands or processor registers, instructing the CPU to direct a hardware device, called the memory controller, to use the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
