| Re: [hatari-devel] Re: FPU update |
[ Thread Index |
Date Index
| More lists.tuxfamily.org/hatari-devel Archives
]
Am 21.01.2017 um 09:44 schrieb Toni Wilen <twilen@xxxxxxxxxx>:
>> I now patched SoftFloat to use 68k format for denormals:
>> https://sourceforge.net/p/previous/code/692/
>>
>> I used pre-processor conditions to make my changes reversible and
>> visible. That does not look very clean, but i want to keep it until i
>> am confident, that the patch works under all conditions. I did some
>> very basic testing and it seems to do the job. But i would be happy
>> if someone could review or test this. I don't want to introduce new
>> problems.
>
> I pushed my changes based on QEMU softfloat, with all your patches added
> and slightly adjusted because QEMU softfloat uses different data type names.
>
> Currently all trigonometric and logarithmic functions use native
> c-library functions. (QEMU does not have any)
>
> I tested it quickly with few Amiga demos that use FPU. (mainly basic
> operations like fmove/fadd/fsub/fcmp/fmul/fmdiv etc.. used)
>
Thank you for the information. In the meantime i made some minor changes to addfloatx80sigs, because the initial denormal patch broke it. The first patch is faulty (but explains the second one). With the second i hope if finally works:
https://sourceforge.net/p/previous/code/694/
https://sourceforge.net/p/previous/code/695/
All in all it is very difficult to make changes to SoftFloat. It was obviously optimized for speed and not readability or maintainability. To make it even harder to read, every function uses different approaches for basically identical operations. Sometimes one gets the feeling this was done intentionally.