MOV and expression source

[Magnum]

Consider LEA as a "trickster", it is not meant to be used regularly for that purpose. You can only multiply registers with 2, 4 and 8 using lea. It is just an option if you want to simplify things every now and then.

Lea is more versatile than that.
LEA can multiply a register by 2,3,4,5,8, and 9.


lea          ebx,[ebx+ebx*8]

[zemtex]

Consider LEA as a "trickster", it is not meant to be used regularly for that purpose. You can only multiply registers with 2, 4 and 8 using lea. It is just an option if you want to simplify things every now and then.

Lea is more versatile than that.
LEA can multiply a register by 2,3,4,5,8, and 9.


lea          ebx,[ebx+ebx*8]

The use of constants when multiplying must be 2, 4 or 8.

[frktons]

Consider LEA as a "trickster", it is not meant to be used regularly for that purpose. You can only multiply registers with 2, 4 and 8 using lea. It is just an option if you want to simplify things every now and then.

Lea is more versatile than that.
LEA can multiply a register by 2,4 or 8.

lea          ebx,[ebx+ebx*8]

The use of constants when multiplying must be 2, 4 or 8.

:lol Magnum is the name on an icecream and he was so sweet and cold to add
some odd numbers to yours.  :lol

Now I've make the sentence in bold characters, just to remember it.  :U

Frank

[Tedd]

The 'scale' value can only 2, 4, or 8, but you may also use lea to get the effect of multiplying by 3, 5, and 9.

lea eax,[2*eax + eax]  { (2*n + n) = 3*n }
lea eax,[4*eax + eax]  { (4*n + n) = 5*n }
lea eax,[8*eax + eax]  { (8*n + n) = 9*n }


With a little extra work, you can also get 7 by copying the value, negating it, and then using that in the 'base' part.




Addressing form is [scale*index + base + displacement] -- all complex forms must be reducible to this form for the assembler to allow it. (Complex constant expressions are allowed only if they can be reduced to a single constant at assembly time, i.e. all values are known.)