[LLVMdev] LLVMdev Digest, Vol 77, Issue 41

[Morten Ofstad]

> On Friday, November 26, 2010 4:32 PM
> Jonas Paulsson <jnspaulsson at hotmail.com> wrote:
>
> Well, the reason DSP compilers would benefit from the new type, is that 
> fixed point numbers must not be optimized
> as integers - eg if two saturated fixed point constants would overflow in 
> an addition operation, the result should as
> well be saturated. Doing this in a series of steps with intrinsics would 
> be quite ridiculous as far as performance goes,
> because this is _supported by the DSP in hardware_ in a single instruction 
> :-)

Isn't it better to add instructions for saturated and/or fixed point 
arithmetic? ... At least that would be consistent with the design of having 
separate instructions for signed and unsigned add etc.

- Morten