[libre-riscv-dev] [isa-dev] Re: FP transcendentals (trigonometry, root/exp/log) proposal

Andrew Waterman andrew at sifive.com
Fri Aug 9 06:39:36 BST 2019

On Thu, Aug 8, 2019 at 8:12 PM lkcl <luke.leighton at gmail.com> wrote:

> On Thursday, August 8, 2019 at 10:14:58 PM UTC+8, andrew wrote:
> > As I mentioned earlier, an instruction being useful is not by itself a
> justification for adding it to the ISA. Where’s the quantitative case for
> these instructions?
> 3D is a Billion dollar mass volume market, proprietary GPUs are going
> after mass volume, inherently excluding the needs of (profitable) long-tail
> markets.

That’s a business justification, not an architectural one, and in any case
it’s a justification for different instructions than the ones you’ve
proposed. The market you’re describing isn’t populated with products that
have ISA-level support for correctly rounded transcendentals; they favor
less accurate operations or architectural support for approximations and
iterative refinement.

> L.
> --
> You received this message because you are subscribed to the Google Groups
> "RISC-V ISA Dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to isa-dev+unsubscribe at groups.riscv.org.
> To view this discussion on the web visit
> https://groups.google.com/a/groups.riscv.org/d/msgid/isa-dev/65871042-2e4a-4a76-869d-e785f5d8bd16%40groups.riscv.org
> .

More information about the libre-riscv-dev mailing list