Le 05/12/2017 à 22:24, william lin a écrit : > > > On Tue, Dec 5, 2017 at 2:01 PM, Laurent Vivier <laur...@vivier.eu > <mailto:laur...@vivier.eu>> wrote: > > Le 05/12/2017 à 18:42, Andreas Grabher a écrit : > > > > Am 05.12.2017 um 10:46 schrieb Laurent Vivier <laur...@vivier.eu > <mailto:laur...@vivier.eu> > > <mailto:laur...@vivier.eu <mailto:laur...@vivier.eu>>>: > > > >> Le 05/12/2017 à 09:56, william lin a écrit : > >>> On Wed, Nov 29, 2017 at 9:19 AM, Thomas Huth <h...@tuxfamily.org > <mailto:h...@tuxfamily.org> > >>> <mailto:h...@tuxfamily.org <mailto:h...@tuxfamily.org>> > >>> <mailto:h...@tuxfamily.org <mailto:h...@tuxfamily.org>>> wrote: > >>> > >>> On 29.11.2017 15:17, Laurent Vivier wrote: ... > >>> > >>> So we can't use these C code directly as it uses helpers from 2b. > >>> However, would it be > >>> ok to write our own set of C code along with the necessary > helpers using > >>> the C and asm > >>> code as reference? (would be part of 2a) > >> > >> I've ported all the functions written by Andreas to QEMU/softfloat 2a > >> and it doesn't need any helpers from 2b. > >> > >> What we need to know is what is the license of his code and if it has > >> been written based on the NetBSD code (BSD license) or from the > libFPSP > >> (proprietary code) [but I think the code is the same...] > >> > >> Thanks, > >> Laurent > > > The functions we are looking for in particular are the transcendental > and trig functions > for floatx80. (sin, cos, twotox, etc..) > > For some context: > We need and implementation of those functions for x86 as it currently > converts floatx80 to > double before calling into glibc and then converting back to floatx80. > This results > in inaccuracies for calculations that use x87 instructions for > intermediate operations. > (https://bugs.launchpad.net/qemu/+bug/645662) > > > I searched through the archive and found your code for this patch: > > https://lists.gnu.org/archive/html/qemu-devel/2017-01/msg03766.html > > ... > > +void HELPER(sincos_FP0_FP1)(CPUM68KState *env) > +{ > + floatx80 res; > + long double val, valsin, valcos; > + > + val = floatx80_to_ldouble(FP0_to_floatx80(env)); > + > + sincosl(val, &valsin, &valcos); > + res = ldouble_to_floatx80(valsin); > + floatx80_to_FP0(env, res); > + res = ldouble_to_floatx80(valcos); > + floatx80_to_FP1(env, res); > +} > > ... > > In relation to the bug, this implementation would provide more accurate > results, but not be consistent with actual x87 hardware. > > If these are not the code you are referring to, then can you please > point to us the > correct ones?
The code ported from "previous" to QEMU can be found here: https://github.com/vivier/qemu-m68k/blob/m68k-dev/fpu/softfloat.c#L7422 but it needs some more polishing. Thanks, Laurent
