help needed on registers!

[RedDevil]

Hi guys!
I found out a problem in my assembly that i cant push a 8 bit register into the stack. i dont know why buy please do have a look at the code below

DrawBox proc
              
                mov bx,0
                mov dl,79
                mov al,num[bx]
                sub dl,al            
                
                add cx,dl           ;<----Problem here
                push cx
                
                call PointCursor
                pop ax
                
                mov ah,09h
                mov bh,00h
                mov al,20h
                mov cx,10D
                mov bl,20h
                int 10h

                ret

DrawBox endp

i tried to 'add cx,dl' to change it to 16 bit but failed. Can any 1 please do help me with this register problem. i just need to push the correct value i minus into the stack without error. Thanks!!

[chemicalNova]

Not sure I completely understand what you're trying to do. But:

mov cl,dl
mov ch,dh
push cx

?

Phreak

[RedDevil]

Hi «°°phReAk°°»

Thanks for your reply. I've found out what's the problem already. Thanks!

[chemicalNova]

Mind showing the solution to us? I'd like to know exactly what you meant..

Phreak

[RedDevil]

sure! here is the code

DrawMiddleBox proc

					push bx
					mov bx,00h
					mov bl,num[bx]
					call PointCursor2
					pop ax

					mov bx,2
					mov cl,num[bx]		;move the height coordinate into cl
					mov dl,num[bx]		;move the height coordinate into bl
					mov bx,0			;get the inputed value from user
					add dl,num[bx]		;plus the height coordinate with the value inputed
					mov num1[1],dl		;temp storage

					mov num1[0],cl

				DrawLoop:				;loop again to draw the next line
						mov bx,0
						mov al,num[bx]	;draw the number of boxes needed
						mov ah,0

						mov cx,ax
						mov ah,09h
						mov bh,00h
						mov al,20h
						
						mov bl,00h
						int 10h

					add num1[0],1				;increment cl by 1
					
					call PointCursor3
					mov cl,num1[0]
					mov dl,num1[1]
					cmp cl,dl
					jl DrawLoop		;jump back loop if cl is smaller or equal to bl
										
					ret

DrawMiddleBox endp

my code is abit complicated to understand. But i've made alot of changes to my code from the 1st code i've posted. I used an array to store my values 1st becore pushing any value to the stack.
Hope you understand what im trying to do. hehe

[Maven]

sure! here is the code

DrawMiddleBox proc

					push bx
					mov bx,00h
					mov bl,num[bx]
					call PointCursor2
					pop ax

					mov bx,2
					mov cl,num[bx]		;move the height coordinate into cl
					mov dl,num[bx]		;move the height coordinate into bl
					mov bx,0			;get the inputed value from user
					add dl,num[bx]		;plus the height coordinate with the value inputed
					mov num1[1],dl		;temp storage

					mov num1[0],cl

				DrawLoop:				;loop again to draw the next line
						mov bx,0
						mov al,num[bx]	;draw the number of boxes needed
						mov ah,0

						mov cx,ax
						mov ah,09h
						mov bh,00h
						mov al,20h
						
						mov bl,00h
						int 10h

					add num1[0],1				;increment cl by 1
					
					call PointCursor3
					mov cl,num1[0]
					mov dl,num1[1]
					cmp cl,dl
					jl DrawLoop		;jump back loop if cl is smaller or equal to bl
										
					ret

DrawMiddleBox endp

my code is abit complicated to understand. But i've made alot of changes to my code from the 1st code i've posted. I used an array to store my values 1st becore pushing any value to the stack.
Hope you understand what im trying to do. hehe

I noticed two things really about you're code. The first one was you move 0 to a register in order to clear it out. My advice to you is to use xor instead.

Instead of saying mov bx, 00h, say: xor bx, bx. It will set everything to 0 and also clear any dependencies that the register has.

I also don't see any real reason to push anything onto the stack. So why not just say mov ax, bx instead of using push and pop.

[RedDevil]

Hi Maven!

Thanks for your opinion! I'm still very n00b at assembly and still learning. I'll take your advice and see what changes i need to do. Thanks again!