An assembly language (or assembler) is a low-level programming language for a computer or other programmable equipment in which there is a correlation between the language and the instruction for machine architecture code. Each machine-oriented language (in professional terminology - “collector”) refers to a specific computer architecture. In contrast, most high-level programming languages are cross-platform, but require interpretation or compilation.
Platform-oriented code can also be called a symbolic language or a set of instructions executed directly by the computer’s central processor. Each program executed by the processor consists of a series of instructions. Machine code is by definition the lowest level of programming visible to a programmer.
Using
, , , . . , . «» , .
1947 ARC2 . SOAP (Symbolic Optimal Assembly Program) IBM 650, 1955 .
. Burroughs MCP (1961 .), Executive Systems Problem Oriented Language (ESPOL). - , IBM, -. COBOL FORTRAN , 1990- .
, . , , . , , , .
, , . . «» . 1980- . . - , . , .
IBM PC DOS, Turbo Pascal , Lotus 1-2-3.
- — 1980- 1990- ( MSX, Sinclair ZX Spectrum, Commodore 64, Commodore Amiga Atari ST). , BASIC , . (IDE) . , Radio Shack TRS-80 , . .
.
. , . .
, . «» x86 . , . , RISC, , CPU.
, Fortran, Algol, Cobol Lisp, 1950- , . , , . , , . , , , , , .
There are two types of assembler programming based on the number of passes through the source (the number of read attempts) to create an object file.
Single-pass assemblers go through the source code once. Any character used before it is defined will require errata at the end of the object code.Multipass assemblers create tables with all characters and their values in the first passes, and then apply the table in subsequent passes to generate the code.— . ( ) . , , ( , ) .
?
, , - ( , - ), . . , . , .
, x86/IA-32 8- . — 10110, 3- , . AL 000, AL 01100001.
: ? «0» «1» , .
: 10110000 01100001.
— . . . (). . , .
. , , , . , , , . .
, . , , , .
, , . , , , . — , :
, , , . , ( ) . . .
— , . , NOP, , .
, .
, . , . ( ) , . .
, , , , , . , , . , .
, . , , .
( ) . , , . , . GOTO. , .
NASM , , , , . .
, , , . , . «» ( ) , , , .