Re: Any more graceful way to saturate adds?

On Apr 22, 1:01 pm, Terje Mathisen  <spamt...@[EMAIL PROTECTED]
> wrote:
> BTW, there is a very sneaky way to avoid that initial jump:
>
> Instead of
>
>   jmp short start
>   next:
>     stosb
> start:
>
> you can instead write:
>
>    mov al,0AAh
> org $-1         ; Back up one byte into the immediate constant above
> next:
>    stosb
>
> I.e. on the first iteration we do a dummy two-byte instruction with a
> one-byte immediate, which we then make sure contains the STOSB opcode
byte.
>
> The gain is that we save one opcode byte (MOV instead of JMP SHORT) and
> a taken branch, so the actual cost of rotating the loop like this is 8
> cycles on the first iteration, instead of 17, and each iteration saves
> two opcode bytes or 8 cycles.

I hate to seem more daft than I already am, but after re-reading the
above for a week I still don't get the trick.  I thought ORG was for
specifying where the assembler assumes the binary code will get
loaded; how does that save two opcode bytes per iteration?