Motorola MC6800 Assembly listing—typical secondary output from an assembler—showing original assembly language and the assembled form,First appeared1949; 70 years ago ( 1949)An assembly language (or assembler language), often abbreviated asm, is any in which there is a very strong correspondence between the program's statements and the.Assembly code is converted into executable machine code by a referred to as an. The conversion process is referred to as assembly, or assembling the.
Saat pertama kali mendengar kata WebAssembly, saya kira kita akan membuat web dengan bahasa assembly. Ternyata bukan. Sekitar dua minggu yang lalu saya mendapatkan kiriman link milis melalui channel @redditprogramming tentang pengumuman WebAssembly. WebAssembly akan segera tersedia di Firefox dan Google Chrome bulan ini dan benar saja, Firefox dan Google Chrome merilis versi terbarunya. Sering disebut juga dengan bahasa komputer atau bahasa pemograman komputer. Bahasa pemrograman juga bisa di katakan sebagai alat untuk menampug suatu himpunan dari aturan sintaks dan semantik yang khususnya dipakai untuk mendefinisikan sebuah program yang ada di komputer. Pengertian Bahasa Pemrograman Lalu, apa itu Bahasa Pemrograman?
Assembly language usually has one statement per machine instruction, but comments and statements that are assembler directives, and symbolic labels of program and memory locations are often also supported.Each assembly language is specific to a particular computer architecture and sometimes to an operating system. However, some assembly languages do not provide specific syntax for operating system calls, and most assembly languages can be used universally with any operating system, as the language provides access to all the real capabilities of the processor, upon which all system call mechanisms ultimately rest. In contrast to assembly languages, most are generally across multiple architectures but require or.Assembly language may also be called symbolic machine code. Contents.Assembly language syntax Assembly language uses a to represent each low-level or, typically also each, etc. Many operations require one or more in order to form a complete instruction. Most assemblers permit named constants, registers, and for program and memory locations, and can calculate for operands. Thus, the programmers are freed from tedious repetitive calculations and assembler programs are much more readable than machine code.
Depending on the architecture, these elements may also be combined for specific instructions or using or other data as well as fixed addresses. Many assemblers offer additional mechanisms to facilitate program development, to control the assembly process, and to aid.Terminology. A macro assembler includes a facility so that (parameterized) assembly language text can be represented by a name, and that name can be used to insert the expanded text into other code. A cross assembler (see also ) is an assembler that is run on a computer or (the host system) of a different type from the system on which the resulting code is to run (the target system). Cross-assembling facilitates the development of programs for systems that do not have the resources to support software development, such as an. MOV AL, 61h; Load AL with 97 decimal (61 hex)In some assembly languages (including this one) the same mnemonic, such as MOV, may be used for a family of related instructions for loading, copying and moving data, whether these are immediate values, values in registers, or memory locations pointed to by values in registers or by immediate (a/k/a direct) addresses. Other assemblers may use separate opcode mnemonics such as L for 'move memory to register', ST for 'move register to memory', LR for 'move register to register', MVI for 'move immediate operand to memory', etc.If the same mnemonic is used for different instructions, that means that the mnemonic corresponds to several different binary instruction codes, excluding data (e.g.
The 61h in this example), depending on the operands that follow the mnemonic. For example, for the x86/IA-32 CPUs, the Intel assembly language syntax MOV AL, AH represents an instruction that moves the contents of register AH into register AL. The hexadecimal form of this instruction is:88 E0The first byte, 88h, identifies a move between a byte-sized register and either another register or memory, and the second byte, E0h, is encoded (with three bit-fields) to specify that both operands are registers, the source is AH, and the destination is AL.In a case like this where the same mnemonic can represent more than one binary instruction, the assembler determines which instruction to generate by examining the operands. In the first example, the operand 61h is a valid hexadecimal numeric constant and is not a valid register name, so only the B0 instruction can be applicable. In the second example, the operand AH is a valid register name and not a valid numeric constant (hexadecimal, decimal, octal, or binary), so only the 88 instruction can be applicable.Assembly languages are always designed so that this sort of unambiguousness is universally enforced by their syntax. For example, in the Intel x86 assembly language, a hexadecimal constant must start with a numeral digit, so that the hexadecimal number 'A' (equal to decimal ten) would be written as 0Ah or 0AH, not AH, specifically so that it cannot appear to be the name of register AH.
(The same rule also prevents ambiguity with the names of registers BH, CH, and DH, as well as with any user-defined symbol that ends with the letter H and otherwise contains only characters that are hexadecimal digits, such as the word 'BEACH'.)Returning to the original example, while the x86 opcode 10110000 ( B0) copies an 8-bit value into the AL register, 10110001 ( B1) moves it into CL and 10110010 ( B2) does so into DL. Assembly language examples for these follow. MOV EAXEBX ; Move the 4 bytes in memory at the address contained in EBX into EAX MOV ESI + EAX , CL; Move the contents of CL into the byte at address ESI+EAX MOV DS, DX; Move the contents of DX into segment register DSIn each case, the MOV mnemonic is translated directly into one of the opcodes 88-8C, 8E, A0-A3, B0-BF, C6 or C7 by an assembler, and the programmer normally does not have to know or remember which.Transforming assembly language into machine code is the job of an assembler, and the reverse can at least partially be achieved by a. Unlike, there is a between many simple assembly statements and machine language instructions. However, in some cases, an assembler may provide pseudoinstructions (essentially macros) which expand into several machine language instructions to provide commonly needed functionality. For example, for a machine that lacks a 'branch if greater or equal' instruction, an assembler may provide a pseudoinstruction that expands to the machine's 'set if less than' and 'branch if zero (on the result of the set instruction)'. Most full-featured assemblers also provide a rich language (discussed below) which is used by vendors and programmers to generate more complex code and data sequences.
Since the information about pseudoinstructions and macros defined in the assembler environment is not present in the object program, a disassembler cannot reconstruct the macro and pseudoinstruction invocations but can only disassemble the actual machine instructions that the assembler generated from those abstract assembly-language entities. Likewise, since comments in the assembly language source file are ignored by the assembler and have no effect on the object code it generates, a disassembler is always completely unable to recover source comments.Each has its own machine language.
Computers differ in the number and type of operations they support, in the different sizes and numbers of registers, and in the representations of data in storage. While most general-purpose computers are able to carry out essentially the same functionality, the ways they do so differ; the corresponding assembly languages reflect these differences.Multiple sets of or assembly-language syntax may exist for a single instruction set, typically instantiated in different assembler programs. In these cases, the most popular one is usually that supplied by the CPU manufacturer and used in its documentation.Two examples of CPUs that have two different sets of mnemonics are the Intel 8080 family and the Intel 8086/8088. Because Intel claimed copyright on its assembly language mnemonics (on each page of their documentation published in the 1970s and early 1980s, at least), some companies that independently produced CPUs compatible with Intel instruction sets invented their own mnemonics.
The Zilog Z80 CPU, an enhancement of the Intel 8080A, supports all the 8080A instructions plus many more; Zilog invented an entirely new assembly language, not only for the new instructions but also for all of the 8080A instructions. For example, where Intel uses the mnemonics MOV, MVI, LDA, STA, LXI, LDAX, STAX, LHLD, and SHLD for various data transfer instructions, the Z80 assembly language uses the mnemonic LD for all of them. A similar case is the NEC V30 and V20 CPUs, enhanced copies of the Intel 8086 and 8088, respectively. Like Zilog with the Z80, NEC invented new mnemonics for all of the 8086 and 8088 instructions, to avoid accusations of infringement of Intel's copyright. Include masm32 include masm32rt.inc; use the Masm32 library.code demomain: REPEAT 20 switch rv ( nrandom, 9 ); generate a number between 0 and 8 mov ecx, 7 case 0 print 'case 0' case ecx; in contrast to most other programming languages, print 'case 7'; the Masm32 switch allows 'variable cases' case 1.
3.if eax 1 print 'case 1'.elseif eax 2 print 'case 2'.else print 'cases 1 to 3: other'.endif case 4, 6, 8 print 'cases 4, 6 or 8' default mov ebx, 19; print 20 stars.Repeat print '.' dec ebx.Until Si gn?; loop until the sign flag is set endsw print ch r$ ( 13, 10 ) ENDM exit end demomain Use of assembly language Historical perspective Assembly languages were not available at the time when the was introduced. 'is credited with inventingassembly language' based on theoretical work she began in 1947, while working on the at following consultation by and her then-future husband with and at the.In late 1948, the (EDSAC) had an assembler (named 'initial orders') integrated into its program. It used one-letter mnemonics developed by, who is credited by the IEEE Computer Society as the creator of the first 'assembler.'
Reports on the EDSAC introduced the term 'assembly' for the process of combining fields into an instruction word. SOAP (Symbolic Optimal Assembly Program) was an assembly language for the computer written by Stan Poley in 1955.Assembly languages eliminate much of the error-prone, tedious, and time-consuming programming needed with the earliest computers, freeing programmers from tedium such as remembering numeric codes and calculating addresses. They were once widely used for all sorts of programming. However, by the 1980s (1990s on ), their use had largely been supplanted by higher-level languages, in the search for improved. Today assembly language is still used for direct hardware manipulation, access to specialized processor instructions, or to address critical performance issues. Typical uses are, low-level, and systems.Historically, numerous programs have been written entirely in assembly language. The (1961) was the first computer for which an operating system was not developed entirely in assembly language; it was written in (ESPOL), an Algol dialect.
Many commercial applications were written in assembly language as well, including a large amount of the software written by large corporations., and some eventually displaced much of this work, although a number of large organizations retained assembly-language application infrastructures well into the 1990s.Most early microcomputers relied on hand-coded assembly language, including most operating systems and large applications. This was because these systems had severe resource constraints, imposed idiosyncratic memory and display architectures, and provided limited, buggy system services.
Perhaps more important was the lack of first-class high-level language compilers suitable for microcomputer use. A psychological factor may have also played a role: the first generation of microcomputer programmers retained a hobbyist, 'wires and pliers' attitude.In a more commercial context, the biggest reasons for using assembly language were minimal bloat (size), minimal overhead, greater speed, and reliability.Typical examples of large assembly language programs from this time are IBM PC operating systems, the compiler and early applications such as the program.
Assembly language was used to get the best performance out of the, a console that was notoriously challenging to develop and program games for. The 1993 arcade game is another example.Assembly language has long been the primary development language for many popular home computers of the 1980s and 1990s (such as the, and ). This was in large part because BASIC dialects on these systems offered insufficient execution speed, as well as insufficient facilities to take full advantage of the available hardware on these systems. Some systems even have an (IDE) with highly advanced debugging and macro facilities. Some compilers available for the and its successors had the capability to combine inline assembly source with high-level program statements. Upon compilation a built-in assembler produced inline machine code.Current usage There have always been debates over the usefulness and performance of assembly language relative to high-level languages.Although assembly language has specific niche uses where it is important (see below), there are other tools for optimization.As of July 2017, the of programming language popularity ranks assembly language at 11, ahead of, for example.
Assembler can be used to optimize for speed or optimize for size. In the case of speed optimization, modern are claimed to render high-level languages into code that can run as fast as hand-written assembly, despite the counter-examples that can be found.
The complexity of modern processors and memory sub-systems makes effective optimization increasingly difficult for compilers, as well as assembly programmers. Moreover, increasing processor performance has meant that most CPUs sit idle most of the time, with delays caused by predictable bottlenecks such as cache misses, operations. ^. James Saxon; William Plette (1962).
– via HathiTrust. use of the term assembly program. System calls often vary, e.g.
VM/CMS; the binary/executable formats for different operating systems may also vary. (PDF).
Assembly language may also be called symbolic machine code. ^ David Salomon (1993). Beck, Leland L. System Software: An Introduction to Systems Programming.
Addison Wesley. Hyde, Randall. 'Chapter 12 – Classes and Objects'. The Art of Assembly Language, 2nd Edition. No Starch Press.
© 2010. (PDF). Intel Corporation. Retrieved 18 November 2010. ^ (PDF). Intel Corporation.
Pp. 442 and 35. Retrieved 18 November 2010.
Actually, this is one of two redundant forms of this instruction that operate identically. The 8086 and several other CPUs from the late 1970s/early 1980s have redundancies in their instruction sets, because it was simpler for engineers to design these CPUs (to fit on silicon chips of limited sizes) with the redundant codes than to eliminate them. Each assembler will typically generate only one of two or more redundant instruction encodings, but a disassembler will usually recognize any of them. Evans, David (2006). University of Virginia.
Retrieved 18 November 2010. Note: AMD manufactured second-source Intel 8086, 8088, and 80286 CPUs, and perhaps 8080A and/or 8085A CPUs, under license from Intel, but starting with the 80386, Intel refused to share their x86 CPU designs with anyone—AMD sued about this for breach of contract—and AMD designed, made, and sold 32-bit and 64-bit x86-family CPUs without Intel's help or endorsement. (PDF). SPARC, International. Archived from (PDF) on 2011-12-10. Retrieved on 2013-07-21.
Microsoft Corporation. Retrieved March 19, 2011. 'The following minor restriction or limitation is in effect with regard to the use of 1401 Autocoder when coding macro instructions.' . Griswold, Ralph E. The Macro Implementation of SNOBOL4.
San Francisco, CA: W. Freeman and Company, 1972 ( ), Chapter 1. Microsoft Corp.
Retrieved 2010-06-22. MVS Software. Retrieved May 25, 2009. Answers.com. Retrieved 2008-06-19. Provinciano, Brian.
Retrieved February 10, 2019. ^ Andrew D. Booth; Kathleen H. Britten (September 1947). Birkbeck College, London.
Retrieved 10 February 2019. The non-original ideas, contained in the following text, have been derived from a number of sources. It is felt, however, that acknowledgement should be made to Prof. John von Neumann and to Dr. Herman Goldstein for many fruitful discussions. see TALK page for details.
Campbell-Kelly, Martin (April 1982). 'The Development of Computer Programming in Britain (1945 to 1955)'. IEEE Annals of the History of Computing. 4 (2): 121–139. Salomon. Retrieved 2012-01-17. Campbell-Kelly, Martin (1980).
'Programming the EDSAC'. IEEE Annals of the History of Computing. 2 (1): 7–36. 1985 Computer Pioneer Award 'For assembly language programming' David Wheeler. (1949). 'The EDSAC - an Electronic Calculating Machine'.
Journal of Scientific Instruments. 26 (12): 385–391. Retrieved 2012-01-17. Archived from on 2008-07-13.
Retrieved 2008-07-25. Barry Kauler (1997). Always the debate rages about the applicability of assembly language in our modern programming world.
Paul Hsieh. Design changes tend to affect performance more than.
One should not skip straight to assembly language until. TIOBE Software.
Rusling, David A. Retrieved Mar 11, 2012.
^. New York Times, John Markoff. Retrieved 2010-03-04. Archived from on 2010-02-05. Retrieved 2010-03-04. Archived from on 2010-03-16.
Retrieved 2010-03-04. Randall Hyde.
Archived from on 2008-06-16. Retrieved 2008-07-03. Archived from on 2010-04-02. Retrieved 2010-03-04. Click, Cliff.
Retrieved May 1, 2014. From the original on 2 July 2008. Retrieved 2008-07-03. Retrieved 2010-03-04.
Apa Itu Implementasi
Archived from on 2012-03-04. Retrieved 2010-09-29. Retrieved 2016-06-01. Hyde, Randall (1996-09-30). Archived from on 2010-03-25. Retrieved 2010-03-05.Further reading. 'An online book full of helpful ASM info, tutorials and code examples' by the ASM Community, archived at the internet archive.
Jonathan Bartlett:. Bartlett Publishing, 2004.Also available online. Robert Britton: MIPS Assembly Language Programming.
Prentice Hall, 2003. Jeff Duntemann: Assembly Language Step-by-Step. Wiley, 2000. Randall Hyde: The Art of Assembly Language.
No Starch Press, 2003.Draft versions as PDF and HTML. Charles W. 2015. Peter Norton, John Socha, Peter Norton's Assembly Language Book for the IBM PC, Brady Books, NY: 1986. Michael Singer, PDP-11. Assembler Language Programming and Machine Organization, John Wiley & Sons, NY: 1980. Dominic Sweetman: See MIPS Run.
Morgan Kaufmann Publishers, 1999. John Waldron: Introduction to RISC Assembly Language Programming. Addison Wesley, 1998.
Dennis Yurichev:External links.
The professor that taught me system programming used what he called 'atomic-C' as a stepping stone between C and assembly. The rules for atomic-C are (to the best of my recollection):.
How To Learn Assembly
only simple expressions allowed, i.e. A = b + c; is allowed a = b + c + d; is not allowed because there are two operators there. only simple boolean expressions are allowed in an if statement, i.e.