The final assignment (#14) of the C course (20465) at The Open University.
Semester 2022 A
Done by Ben Avrahami and Gal Ben Artzi
The Project was graded 100!
The project was coded and compiled using Ubuntu, but it may run on all Linux versions.
Use makefile to compile the project like this:
make
After preparing assembly files with an .as extension, open terminal and pass file names as arguments (without the file extensions) as following:
As for the files x.as, y.as, hello.as we will run:
assembler x y hello
The assembler will generate output files with the same filenames and the following extensions:
-
.ob- Object file -
.ent- Entries file -
.ext- Externals file
An example of input and output files can be found under the 'tests' folder.
A directive line of the following structure:
-
An optional preceding label. e.g.
PLACE1:. -
A directive:
.data,.string,.struct,.entryor.extern. -
Operands according to the type of the directive.
This directive allocates memory in the data image for storing received integers later in memory (also increases the data counter and updates the symbol table). The parameters of
.dataare valid integers (separated by a comma).
e.g.LABEL1: .data +7, -56, 4, 9.This direcive receives a string as an operand and stores it in the data image. It stores all characters by their order in the string, encoded ny their ASCII values. e.g.
STRING1: .string "abcdef"is a valid directive.This directive outputs a received name of a label to the symbol table, so that later it will be recognized by other assembly files (and they would be able to use it). e.g.
; file1.as .entry HELLO HELLO: add #1, r1This directive receives a name of a label as a parameter and declares the label as being external (defined in another file) and that the current file shall use it.
This way, the directive.extern HELLOinfile2.aswill match the.entrydirective in the previous example.