Re: Lab4

James Wu (james_wu@telus.net) Tue, 29 Feb 2000 18:57:33 -0800 

From: "James Wu" <james_wu@telus.net>
Subject: Re: Lab4
Date: Tue, 29 Feb 2000 18:57:33 -0800



Hi Jonathan:


> --------------------------------------------------------------------------
-------
> I am a little confused by the specs for the assembly
> code on page 3.
>
> Q.1
> "...a string consisting of your name, student number
> followed by a carriage-return and a line feed"
> Does anyone know how to  put a carriage return and
> line feed in a string?

I have the same question about that, too, but what I did was the following:

'my string, 1234567',0dh, 0ah, 0

0dh (in hex) is the ASCII for carriage return.
0ah (in hex) is the ASCII for line feed.
0 is the ASCII for "null" char.

>
> Q.2
> "returns control to DOS if the current character is
> zero"
>
> Is this because no one has a zero in their student
> number?
>

I recall in Monday's lecture that Dr. Casas mentioned the "zero" refers to
the NULL char in the ASCII set (i.e. ASCII value 0).  I also recall that a
string ends with a NULL char; this is why the assembly program checks for
this string terminating char.  I think the "zero" you are referring to is
the "0" char in the ASCII set (i.e. value 30h).

Hope this helps :)

James