HI MY FELLOW NAIRALAND
PLEASE I WAS GIVEN AN ASIEGNMENT ON THIS TOPIC 2 PASS ASSEMBLER. (computer programming)
PLEASE WHO CAN HELP ME ON AND EXPLAIN THIS TO ME, THE USES, FUNCTION, IMPORTANTS ETC

I WILL BE GRATEFUL.

THANKS
email is scanteebest@yahoo.co.uk

please help me is very urgent.

thanks one more

Hi,

Though you did not specify the platform/architecture you are building an assembler for, the idea is somewhat platform independent. . .(have different possible approach).

In basic, the assembler generates machine codes from an assembly language code. A simply way of achieving this is through the 2-pass organization. The need for this arises from consideration of the assembler functions and the nature of assembly language code. The primary ones being:
[list]
[li]The assembler generates machine code output.[/li]
[li]The assembler generates memory addresses for program labels.[/li]
[li]Assembly language control structures(jumps) cannot be written without forward reference. A forward reference occurs when you use a label in an operand that appears earlier in the code than its definition.[/li]
[/list]

Clearly now, the reasons for the 2-pass organization is necessitated by the facts that:
[list]
[li]The memory address for a label cannot be assigned until its definition has been read.[/li]
[li]Code generation for jumps and branches requires knowing the address of the jump or branch target.[/li]
[/list]

During the first pass, the assembler is assigning memory addresses to labels. Machine code is generated during the second pass.


Assembler technology is so wide to be covered here in full details. Please, the links below refers you to sites where you can find more information about this, as well as some basic algorithm for this.
[url=http://www.d.umn.edu/~gshute/asm/assemblers.html]Link 1: Basic Descriptions [/url]
Link 2: Difference between 1-pass and 2-pass
Link 3: Sample Algorithm
[url=http://www.cs.uiowa.edu/~rus/Courses/SysSoft/Notes/chap16a2.pdf]Link 4: Book For Assembly Principles[/url]

Like I said, this is just the basic/algorithm I have provided. You will then need to develop the actual assembler in your choice high-level programming language.

Cheers! and do google for some more info.