Re: Any more graceful way to saturate adds?

Terence wrote:
> On Apr 13, 5:29 am, Robert Redelmeier <red...@[EMAIL PROTECTED]
> wrote:
> 
>> CF is also set with two byte adds.
> 
> But this never occurs with adding one byte to one bye in two-byte
> registers (with zero bits to the left). The objective is to count to
> no more than 254 since 255 itself is the overflow signal.

That's a red herring:

It really doesn't matter if you say:

   if ((sum = a+b) > 254) sum = 255;

or if you write:

   if ((sum = a+b) > 255) sum = 255;

Please notice that as long as the sum is above 254, saturation will 
always return 255, and at that point there is no way to determine if 
this was the result of saturation after overflow, or simply because the 
sum actually was 255!

OK?

Terje

-- 
- <Terje.Mathisen@[EMAIL PROTECTED]
>
"almost all programming can be viewed as an exercise in caching"