sal reg,variable

[Ric]

does anyone know if it is possible to shift a register by a variable instead of an immediate value?
eg
sal dword [mem], eax
I can always make a loop to do it but it would be nice if i could do it in one line.
Regards Ric

[RichardRussell]

does anyone know if it is possible to shift a register by a variable instead of an immediate value?

Yes. In IA-32:

Code: Select all

0FA31CF9 D3 25 F3 20 A3 0F              sal dword [mem], cl

or in x86-64:

Code: Select all

000000000D791D17 D3 25 F4 03 00 00               sal dword [rel mem], cl

[Ric]

Thanks for the swift reply Richard