Heading Details

Posted on 2004-03-26
Last Modified: 2012-03-15
Hello, thanks for reading my question.

I was wondering if someone could explain what "heading details" were, and why they are required by some assemblers and not others.

I seem to remember trying to write a simple program, but it wouldnt assemble because it was requiring all this additional code (that didn't seem to make much sense to me).  Is this the same thing?

I hope my question makes sense.  I'm kinda new to assembly and have a lot of questions...

Thanks in advance.

Question by:michaelman
LVL 12

Accepted Solution

stefan73 earned 25 total points
ID: 10685254
Hi michaelman,
You mean all the lines about code model and such?

They're required for the assembler in order to create a binary - this information is used to create the appropriate sections, relocation entries, etc.


LVL 12

Expert Comment

ID: 10685263
Provide an example, and I'll see.

Author Comment

ID: 10685334
The following code was included in MASM.  The file is called "minimum.asm", which leads me to believe its the smallest code that can be assebled (?).

At any rate, none of the tutorials I have read provide much information about the first few lines:

                 model tiny

                   org 100h
                   jmp start
                  mov ax, 4c00h
                  int 21h

Assisted Solution

manish_regmi earned 25 total points
ID: 10690511
 those "heading details" are required by the assembler the output you want.
.model tiny is a model directive. it will tell the assembler to use tiny memory model.
The executable code contains segments code, data and stack.
so you need to tell the assembler to put which code in which segment.

hi, if you are newbie, the book below will be a good start

regards manish

Expert Comment

ID: 10698970
        org 100h

this tells the assembler that the code segment (area of memory that will hold the instructions as opposed to data) begins at address 100 hex.
org 100h simply means origin 100h.

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