Program Translation

The assembly language statement says the same thing as the machine language instruction, but must be translated into a bit pattern before it can be executed. An assembly language program consists of assembly language statements, statements that define data, and some additional information that helps in the translation. Here is a fragment of an assembly language program and its translation into bit patterns.

machine instructions                             assembly statements

0011 0100 0000 0001 0000 0000 0000 1001          ori  $1, $0, 9
0000 0000 0100 0001 0000 0000 0001 1000          mult $2, $1
0000 0000 0000 0000 0100 0000 0001 0010          mflo $8 
0011 0100 0000 0001 0000 0000 0000 1001          ori  $1, $0, 5
0000 0000 0100 0000 0000 0000 0100 1000          div  $8, $1

Years ago, to run a program written in FORTRAN you used a compiler to translate the program into assembly language. Then you used an assembler to translate the assembly language into machine language. Finally, you loaded the machine language into the computer's memory and executed your program.

Modern compilers usually translate a source program directly into machine language which is contained in a file called an object module (more on this later). But for now let us think about translating FORTRAN into assembly language.

FORTRAN is a high level language. It is intended to run on all types of computers regardless of architecture. FORTRAN statements can be written without knowing the architecture of the computer, and can be run on any computer (after translation).