Label? - Forums - ASM Community



.DATA
Items label word
	db	BLOCK,	COLOR1,	176,  40,  40,  40
	db	BLOCK,	COLOR1,	214,   1,   1,   1
	db	BLOCK,	COLOR1,	176,  40,  40,	40
	db	BLOCK,	COLOR1,	214,   1,  1,	 1
end


 Hi there, a moment ago I was studying someone else code
 and I ecountered the code above. What I want to know is
 the second line (Items label word) what does it do (and
 the meaning of it) and how you would access it.

 Thanx for your help.

Posted on 2001-04-25 20:56:00 by disease_2000

Label?

It creates a label. The type it gets is the one in the LABEL directive. Notice that the given label is declared to be of type WORD, but that the first data is created as a BYTE type. There's probably some optimization going on where the values in the table are loaded/modified/stored two bytes at time, instead of one at a time. If it were written as


Items db   BLOCK,   COLOR1,   176,  40,  40,  40
      db   BLOCK,   COLOR1,   214,   1,   1,   1
      db   BLOCK,   COLOR1,   176,  40,  40,   40
      db   BLOCK,   COLOR1,   214,   1,  1,    1

then everywhere you wanted to move two bytes requires writing the WORD PTR type override, as follows:


      mov  ax,word ptr Items    ; get block and color of first entry
      mov  bx,word ptr Items[2] ; get next two numbers
      mov  cx,word ptr Items[4] ; get last two numbers of first entry

With the LABEL directive, you can eliminate WORD PTR in the three example moves. If MASM allowed


Items dw   0 dup(?)  ; Don't generate any data

it would accomplish the same task.

Posted on 2001-04-25 21:52:00 by tank

Label?

Thanx, you've made it very clear (good explaination!)

Posted on 2001-04-25 22:48:00 by disease_2000