Var db 255       

Var db "qwerty"     

Var:
        db 'q','w','e','r','t','y'
; or
Var:
        db 'q'
        db 'w'
        db 'e'
        db 'r'
        db 't'
        db 'y'    

; create 32BIT integer variable. example:

; variable v, 123 ; output: v dd 123

macro variable name, value
 { name dd value }

; supports: variable v=123. [va] creates
; a variable list of arguments. this
; version just replaces , with =

; variable v=123 ; output: v dd 123 (same)

macro variable [p] { ; p = va list
common               ; do this once
 match a==b, p \{    ; extract a=b from p
  a dd b             ; name dd value
 \}
}

; supports 2+ names/values on same line:

; variable a=1, b=2, c=3

; forward iterates/loops through each
; argument/parameter separated with commas:
; a=1, b=2, c=3

macro variable [p] {
forward              ; for i=0 to va.n {
 match a==b, p \{    ; name=value (p=va[i])
  a dd b
 \}
; ...                ; next va[i++] }
}

; supports variables with no initial value
; and error checking. default=0 if no value
; is specified

; in the following, name=value must be
; matched before name by itself (with no
; =value) or there would be a partial match.

; in the second match, =0 ?s ensures there
; was no previous match: "if ?s=0 then get
; name/a from p". in effect, "=0 ?s"
; creates a chain of "else-if match"s

macro variable [p] {
forward              ; for i=0 to va.n
 define ?s 0
 match a==b, p \{    ; name=value
  a dd b
  define ?s 1        ; success
 \}
 match =0 a, ?s p \{ ; name by itself
  a dd 0             ; name=0
  define ?s 1        ; success
 \}
if ?s eq 0           ; neither match
 'Syntax error'      ; was successful
end if
}

; example variables...

variable a=123, b=456, c, d=789

; output: 4 lines...

; a dd 123
; b dd 456
; c dd 0   ; c=0
; d dd 789    

I started to learn asm just 30 minutes ago, so if my question sounds stupid, please take it easy Let's say, I declare one byte length variable, e.g.

Code:

Var db 255       

This is OK. But, let's say:

Code:

Var db "qwerty"     

How can one-byte variable contain a 6 byte length string?

uart777, many thanks, this will come in handy.

Any questions? Please don't hesitate to ask.

There are different ways to define labels. The simplest is to follow the name of label by the colon. It defines the label whose value is equal to offset of the point where it’s defined. ... The other way is to follow the name of label (without a colon) by some data directive. It defines the label with value equal to offset of the beginning of defined data

Var1 db 255    

Var1: db 255    

data1   db 0
data2:  db 0

        mov  eax, [data1]
        mov  al,  [data1]
        mov  eax, dword [data1]
        mov  eax, [data2]    

data1 db 0
data2: db 0

data1   db 0
data2:  db 0
data3 = 1

        mov  eax, [data3]    

use32
label a at eax*2+ecx; sizeless, but different ;-)
mov eax, [a+1000-eax+3*ecx]    

Code:

Var db "qwerty"     

How can one-byte variable contain a 6 byte length string?

varx    db  100h dup(0) 

vary    db  100h dup('blablabla')
    

Code:

label a at eax*2+ecx; sizeless, but different