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<title>01 TAJGA FASM Tutorial</title>
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<center><b>CHAPTER 1 - Getting started</b></center><br><br>
Here i predict you have some basic information about what are bytes and some
idea what is ASCII code. Maybe i will describe ASCII in later versions of
tutorial.<br><br>
First try to compile empty source file. Just create empty file "empty.asm"
and write
<blockquote class="console">
fasm empty.asm empty.bin
</blockquote>
into command line. You should see that
file "empty.bin" is created, and it's length is zero.<br><br>
Now we will create binary file containing some data. Create text file
containing line
<blockquote class="code"><pre>
db <font color=#bb0000>'a'</font>
</pre></blockquote>
and compile it (i hope you already know how). When you look at created file
you should see it is 1 byte long and it contains character "a". <br><br>
Now let's analyze (?) source:
<code>db</code> is "directive" (directive is command to compiler, remember this!) which
means "define byte". So this directive will put byte into destination file.
Value of byte should follow this directive. For example <code>db 0</code> will insert
byte of value 0 to destination file. But if you want to enter some character,
you would have to remember it's ASCII value. In this case, you can enter the
character enclosed in apostrophes (') and compiler will "get" it's value for
you. This is that code works.<br><br>
<blockquote class="term">
<b>directive</b><br>
command to compiler
</blockquote>
Now let's make file with more than one character. It will be:
<blockquote class="code"><pre>
db <font color=#bb0000>'1'</font>
db <font color=#bb0000>'2'</font>
db <font color=#bb0000>'3'</font>
</pre></blockquote>
How this work is clear, i think, it stores three bytes into destination file,
which should now contain simple line with <code>123</code>. By the way you can't write
<blockquote class="code"><pre>
db <font color=#bb0000>'1'</font> db <font color=#bb0000>'2'</font> db <font color=#bb0000>'3'</font>
</pre></blockquote>
because every directive must be on separate line. But if you want to define
more bytes, you can use simple <code>db</code> directive followed by more values,
sperated by commas (,):
<blockquote class="code"><pre>
db <font color=#bb0000>'1'</font><font color=#333399>,<font color=#bb0000>'2'</font>,<font color=#bb0000>'3'</font></font>
</pre></blockquote>
This will produce file with <code>123</code> too.<br><br>
But what if you want to define something longer, for example file containing
<code>This is my first long string in FASM</code>? You could write
<blockquote class="code"><pre>
db <font color=#bb0000>'T'</font><font color=#333399>,<font color=#bb0000>'h'</font>,<font color=#bb0000>'i'</font>,<font color=#bb0000>'s'</font></font> etc...
</pre></blockquote>
but it is not very nice. For this reason, if you want define more
consecutive characters using <code>db</code> , you can use this form:
<blockquote class="code"><pre>
db <font color=#bb0000>'This is my first long string in FASM'</font>
</pre></blockquote>
So you have to enclose whole text in quotes. You can use this too:
<blockquote class="code"><pre>
db <font color=#bb0000>'This is my first long string in '</font><font color=#333399>,<font color=#bb0000>'FASM'</font></font>
</pre></blockquote>
or
<blockquote class="code"><pre>
db <font color=#bb0000>'Thi'</font><font color=#333399>,<font color=#bb0000>'s is my first lo'</font>,<font color=#bb0000>'ng string in'</font>,<font color=#bb0000>' FASM'</font></font>
</pre></blockquote>
etc.<br><br>
<blockquote class="term">
<b>string, quoted string</b><br>
Text enclosed in apostrophes is called "string". In general, "string" is
array of characters. Term used for string inside source code is called
"quoted string".
</blockquote>
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