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

[lkcl]

On Thursday, August 8, 2019 at 6:09:28 PM UTC+8, Jacob Lifshay wrote:

> 
> maybe a solution would be to add an extra field to the fp control csr (or isamux?) to allow selecting one of several accurate or fast modes:

No definitely not ISAMUX/ISANS, its purpose is for switching (paging in) actual opcodes.  Not quite true, LE/BE kinda flips in LE variants of LD/ST.

An FP CSR (dedicated or fields) makes more sense I think because it's quite a few bits, and I can see some potential value in the same bits being applied to F, G, H and Q as well.

Hmmm