|
Literal Pool
In computer science, and specifically in compiler and assembly language#Assembler, assembler design, a literal pool is a lookup table used to hold Literal (computer programming), literals during assembly and execution (computers), execution. Multiple (local) literal pools are typically used only for computer architectures that lack branch instructions for long jumps, or have a set of instructions optimized for shorter jumps. Examples of such architectures include the IBM System/360 and its successors, which had a number of instructions which took 12-bit address offsets. In this case, the compiler would create a literal table on every 4K page; any branches whose target was less than 4K bytes away could be taken immediately; longer branches required an address lookup via the literal table. The entries in the literal pool are placed into the object code, object relocation table during assembly, and are then resolved at Linker (computing), link edit time. The ARM architecture also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Computer Science
Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, applied disciplines (including the design and implementation of Computer architecture, hardware and Software engineering, software). Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and preventing security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Programming language theory considers different ways to describe computational processes, and database theory concerns the management of re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
System-on-chip
A system on a chip (SoC) is an integrated circuit that combines most or all key components of a computer or electronic system onto a single microchip. Typically, an SoC includes a central processing unit (CPU) with memory, input/output, and data storage control functions, along with optional features like a graphics processing unit (GPU), Wi-Fi connectivity, and radio frequency processing. This high level of integration minimizes the need for separate, discrete components, thereby enhancing power efficiency and simplifying device design. High-performance SoCs are often paired with dedicated memory, such as LPDDR, and flash storage chips, such as eUFS or eMMC, which may be stacked directly on top of the SoC in a package-on-package (PoP) configuration or placed nearby on the motherboard. Some SoCs also operate alongside specialized chips, such as cellular modems. Fundamentally, SoCs integrate one or more processor cores with critical peripherals. This comprehensive integr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
String Literal
string literal or anonymous string is a literal for a string value in the source code of a computer program. Modern programming languages commonly use a quoted sequence of characters, formally "bracketed delimiters", as in x = "foo", where , "foo" is a string literal with value foo. Methods such as escape sequences can be used to avoid the problem of delimiter collision (issues with brackets) and allow the delimiters to be embedded in a string. There are many alternate notations for specifying string literals especially in complicated cases. The exact notation depends on the programming language in question. Nevertheless, there are general guidelines that most modern programming languages follow. Syntax Bracketed delimiters Most modern programming languages use bracket delimiters (also balanced delimiters) to specify string literals. Double quotations are the most common quoting delimiters used: "Hi There!" An empty string is literally written by a pair of quotes with n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Java Virtual Machine
A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages that are also compiled to Java bytecode. The JVM is detailed by a specification that formally describes what is required in a JVM implementation. Having a specification ensures interoperability of Java programs across different implementations so that program authors using the Java Development Kit (JDK) need not worry about idiosyncrasies of the underlying hardware platform. The JVM reference implementation is developed by the OpenJDK project as open source code and includes a JIT compiler called HotSpot. The commercially supported Java releases available from Oracle are based on the OpenJDK runtime. Eclipse OpenJ9 is another open source JVM for OpenJDK. JVM specification The Java virtual machine is an abstract (virtual) computer defined by a specification. It is a part of the Java runtime environment. The garbage collection ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
GNU Compiler Collection
The GNU Compiler Collection (GCC) is a collection of compilers from the GNU Project that support various programming languages, Computer architecture, hardware architectures, and operating systems. The Free Software Foundation (FSF) distributes GCC as free software under the GNU General Public License (GNU GPL). GCC is a key component of the GNU toolchain which is used for most projects related to GNU and the Linux kernel. With roughly 15 million lines of code in 2019, GCC is one of the largest free programs in existence. It has played an important role in the growth of free software, as both a tool and an example. When it was first released in 1987 by Richard Stallman, GCC 1.0 was named the GNU C Compiler since it only handled the C (programming language), C programming language. It was extended to compile C++ in December of that year. Compiler#Front end, Front ends were later developed for Objective-C, Objective-C++, Fortran, Ada (programming language), Ada, Go (programming la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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 similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
ZSeries
IBM Z is a family name used by IBM for all of its z/Architecture mainframe computers. In July 2017, with another generation of products, the official family was changed to IBM Z from IBM z Systems; the IBM Z family will soon include the newest model, the IBM z17, as well as the z16, z15, z14, and z13 (released under the IBM z Systems/IBM System z names), the IBM zEnterprise models (in common use the zEC12 and z196), the IBM System z10 models (in common use the z10 EC), the IBM System z9 models (in common use the z9EC) and ''IBM eServer zSeries'' models (in common use refers only to the z900 and z990 generations of mainframe). Architecture The ''zSeries,'' ''zEnterprise,'' ''System z'' and ''IBM Z'' families were named for their availability – ''z'' stands for zero downtime. The systems are built with spare components capable of hot failovers to ensure continuous operations. The IBM Z family maintains full backward compatibility. In effect, current systems are the direc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
System/390
The IBM System/390 is a discontinued mainframe product family implementing ESA/390, the fifth generation of the System/360 instruction set architecture. The first computers to use the ESA/390 were the Enterprise System/9000 (ES/9000) family, which were introduced in 1990. These were followed by the 9672, Multiprise, and Integrated Server families of System/390 in 1994–1999, using CMOS microprocessors. The ESA/390 succeeded ESA/370, used in the Enhanced 3090 and 4381 "E" models, and the System/370 architecture last used in the IBM 9370 low-end mainframe. ESA/390 was succeeded by the 64-bit z/Architecture in 2000. History On September 5, 1990, IBM published a group of hardware and software announcements, two of which included overviews of three announcements: * System/390 (S/390), as in 360 for 1960s, 370 for 1970s. * Enterprise System/9000 (ES/9000), as in 360 for 1960s, 370 for 1970s. * Enterprise Systems Architecture/390 (ESA/390) was IBM's last 31-bit-address/3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Addressing Mode
Addressing modes are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressing modes that are defined in a given instruction set architecture define how the machine language instructions in that architecture identify the operand(s) of each instruction. An addressing mode specifies how to calculate the effective memory address of an operand by using information held in registers and/or constants contained within a machine instruction or elsewhere. In computer programming, addressing modes are primarily of interest to those who write in assembly languages and to compiler writers. For a related concept see orthogonal instruction set which deals with the ability of any instruction to use any addressing mode. Caveats There are no generally accepted names for addressing modes: different authors and computer manufacturers may give different names to the same addressing mode, or the same names to different addressing modes. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Program Counter
The program counter (PC), commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer, is a processor register that indicates where a computer is in its program sequence. Usually, the PC is incremented after fetching an instruction, and holds the memory address of (" points to") the next instruction that would be executed. Processors usually fetch instructions sequentially from memory, but ''control transfer'' instructions change the sequence by placing a new value in the PC. These include branches (sometimes called jumps), subroutine calls, and returns. A transfer that is conditional on the truth of some assertion lets the computer follow a different sequence under different conditions. A branch provides that the next instruction is fetched from elsewhere in memory. A subroutine call not only branches but saves the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Global Offset Table
The Global Offset Table, or GOT, is a section of a computer program's (executables and shared libraries) memory used to enable computer program code compiled as an ELF file to run correctly, independent of the memory address where the program's code or data is loaded at runtime. It maps symbols in programming code to their corresponding absolute memory addresses to facilitate Position Independent Code (PIC) and Position Independent Executables (PIE) which are loaded to a different memory address each time the program is started. The runtime memory address, also known as absolute memory address of variables and functions is unknown before the program is started when PIC or PIE code is run so cannot be hardcoded during compilation by a compiler. The Global Offset Table is represented as the .got and .got.plt sections in an ELF file which are loaded into the program's memory at startup. The operating system's dynamic linker updates the global offset table relocations (symbol to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Table Of Contents (computer Science)
A table of contents (or simply contents, abbreviated as TOC), is a list usually part of the front matter preceding the main text of a book or other written work containing the titles of the text's sections, sometimes with descriptions. History Pliny the Elder credits Quintus Valerius Soranus (d. 82 BC) as the first author to provide a table of contents to help readers navigate a lengthy work. Classical Origins The Roman writer Quintus Valerius Soranus (d. 82 BCE) is credited as the first to attach a list of contents to a written work, according to the Roman historian Pliny the Elder. In his ''Natural History'', Pliny writes: "Soranus was the first to include a list of his book’s chapters to help the reader understand its content."Pliny's own table of contents for his encyclopedic ''Historia naturalis'' ("Natural History") may be viewed onlinin Latinanin English(following dedication). In Indian and Chinese Civilizations In ancient Sanskrit literature, works such as the ''Su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
