6. Scaling Factors

You can use scaling to index into arrays with different sizes of elements.

For example, the scaling factor is

• 1 for byte arrays (no scaling needed),

• 2 for word arrays,

• 4 for doubleword arrays,

• and 8 for quadword arrays.

There is no performance penalty for using a scaling factor.

Scaling is illustrated in the following examples:

    mov     eax, darray[edx*4]     ; Load double of double array
    mov     eax, [esi*8][edi]      ; Load double of quad array
    mov     ax, wtbl[ecx+2][edx*2] ; Load word of word array