[fpc-devel] I've asked this before, but perhaps I wasn't specific enough that time: what do ...

Nikolai Zhubr n-a-zhubr at yandex.ru
Sun Dec 19 18:22:56 CET 2021


19.12.2021 19:28, J. Gareth Moreton via fpc-devel:
> To throw my hat into the ring, I'd be willing to help out with
> developing some library routines.  I did experiment once with using a
> truncated and factorised MacLaurin series to calculate Double-precision
> sin and cos simultaneously in native SSE2 (with sin and cos filling two
> elements of the same register), mainly so one wouldn't be forced to use
> the floating-point stack on 64-bit (the speed was about the same).  For
> 128-bit though, I imagine it would have to be fully emulated, down to
> how the mantissa and exponent are interpreted.  I admit I haven't
> studied the sfpu128 unit yet.  If you need "log" and "exp" implmented in
> software, if you can give me the exact requirements and specifications,
> I'll see what I can do.

Well x87 does include log and exp (kind of), so bochs does too. It is 
known to successfully run lots of ancient 86/87 software, so I'd suppose 
this x87 emulation should be pretty much stable.
Apparently, x87 implementation in bochs is not tied to any sort of 
host-side floating-point capabilities, so it is portable. IIRC some 
people reported they used it on ARM.


> Gareth aka. Kit

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