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

lkcl . luke.leighton at gmail.com
Thu Aug 8 15:01:15 BST 2019

On Thu, Aug 8, 2019 at 11:00 AM Andrew Waterman <andrew at sifive.com> wrote:

>> wait... hang on: there are now *four* potential Platforms against which this statement has to be verified.  are you saying that for a *UNIX* platform that correctly-rounded transcendentals are potentially undesirable?
> The sentence you quoted began with the adjective "ISA-level".  We happily provide correctly rounded transcendental math on Linux as-is.

i am very confused.  we seem to be talking at cross-purposes, and i
have no idea where the confusion lies.

it appears that you are rejecting the possibility of providing
ISA-level support for transcendental and trigonometric operations for
*four* possible platform scenarios just because "correctly rounded
transcendental math is provided on linux".  this has me utterly

particularly when, even *on* one of those platforms - the standard
UNIX Platform - Jacob pointed out that there may exist
High-Performance Server scenarios that would want the increased
performance - *on linux* - that such ISA-level support would provide.

i apologise: i don't understand what is going on.

why would even *one* argument "we provide accurate SOFTWARE math
libraries on linux" be reasonable cause to reject HARDWARE support for
the same?

why would that argument be relevant for THREE OTHER completely
different Platform Profiles?

i don't understand.


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