My task is to sum AX and BX to AX, without using "MOV" or "LEA" operands. I am bit stuck here, can you help me please?
; AX need to be 15, using ONLY 'mov' and 'lea'.
; Do NOT use arithmetic instrutions (add, inc, mul, etc.)
mov ax,10
mov bx,4
lea cx,ax
lea cx, [cx+bx]
What am i doing wrong? sorry for my mistakes, i am a newbie.
The not so obvious thing about lea in 16-bit addressing mode today is that not any register can be used as src operand. If I recall correctly, you can only add base pointer (bp) or index (bx) to source or destination index (si or di) registers. dest operand can be any general-purpose register.
The following are allowed:
lea ax, [si + bx]
lea ax, [di + bx]
lea ax, [si + bp]
lea ax, [di + bp]
At this point I believe you've already got how to do the task:
mov si, ax ; si = ax
lea ax, [si + bx] ; ax = ax + bx