Value is assigned to it when its declared the

value is assigned to it when it’s declared.
The pseudoinstructions
db
,
dw
,
dd
,
dq
,
dt
,
ddq
and
do
help us to
initialize a memory location with some data, and with using labels
when can mimic the concept of initialized variables in C. As an exam-
ple, let’s consider
db
which declares and initializes a byte of data, the
second letter of
db
means bytes.
23 db ’a’
The above example reserves a byte in the memory, this is the
decla-ration step, then the character
a
will be stored on this reserved
byte of the memory, which is the initialization step.
5888 db ’a’, ’b’, ’c’
In the above example we have used comma to declare three bytes
and store the values
a
,
b
and
c
respectively on them, also, on memory
23
In linguistics, which is the science that studies languages, a prefix is a word
(actually a morpheme) that is attached in the beginning of another word and
changes its meaning, for example, in un do, un is a prefix.
24
For example, in algorithm design which is a branch of computer science, the term
pseudo code means a code that is written in a fake programming language. Another
example is the word pseudo science: A statement is a pseudoscience when it is
claimed to be a scientific fact, but in reality it is not, that is, it doesn’t follow the
scientific method.
25 Unless, of course, they are provided in the other assembler as pseudoinstructions.
26 It is important to note that declaring a function in C differs from defining a function,
the following declares a function: int foo(); You can see that the code block (the
implementation) of foo is not a part of the declaration, once the code block of the
function is presented, we say this is the definition of the function.

1.5 writing the boot loader 30
these values will be stored contiguously, that is, one after another, the
memory location (hence, the memory address) of the value
b
will be
right after the memory location of value
a
and the same rule applies for
c
. Since
a
,
b
and
c
are of the same type, a character, we can write the
previous code as the following and it gives as the same result.
5888
db ’abc’
Also, we can declare different types of data in the same source line,
given the above code, let’s say that we would like to store the number
0
after the character
c
, this can be achieved by simply using a comma.
1 db ’abc’, 0
Now, to make this data accessible from other parts of the code, we
can use a label to represent the starting memory address of this
data. Consider the following example, it defines the label
our
_
variable
,
after that, we can use this label to refer to the initialized data.
1 our
_
variable db ’abc’, 0
repeating with
times
To repeat some source line multiple times, we
can use the pseudoinstruction
times
which takes the num-ber of
repetitions as first operand and the instruction that we would like to
execute repeatedly as second operand. The following example prints
S
five times on the screen.