English Amiga Board


Go Back   English Amiga Board > Support > support.WinUAE

 
 
Thread Tools
Old 09 November 2016, 23:12   #1
michaljarz
Registered User

 
Join Date: Jul 2014
Location: Katowice/Poland
Posts: 46
Emulated FPU precision

Hi.
Last time I run Mand2000:
http://aminet.net/gfx/fract/Mand2000demo.lha

When I started to zoom fractal, I saw some distortion. I compared it with my Amiga, where it turned out that everything was OK. The problem arises only when emulation is enabled the FPU. When the WinUAE does not use the FPU then everything is OK.

Screenshots show what's going on.
Problems arise when zoomed in row x 44 and larger.

EDIT: I tested different settings (JIT on/off, 040/881/882 fpu, more compatible, unimplemented fpu instructions), each time the same effect.
(sorry for my english, I often use the translator)
Attached Thumbnails
Click image for larger version

Name:	mand_1.jpg
Views:	165
Size:	51.6 KB
ID:	50777   Click image for larger version

Name:	mand_2.jpg
Views:	154
Size:	71.0 KB
ID:	50778   Click image for larger version

Name:	mand_3.jpg
Views:	145
Size:	71.9 KB
ID:	50779   Click image for larger version

Name:	mand_4.jpg
Views:	154
Size:	67.3 KB
ID:	50780  

Last edited by michaljarz; 09 November 2016 at 23:22.
michaljarz is offline  
Old 10 November 2016, 00:33   #2
PeterK
Registered User
 
Join Date: Apr 2005
Location: Hangover
Posts: 2,630
The difference between floatingpoint calculations in WinUAE and on a real Amiga with an FPU is that the FPU emulation in WinUAE is restricted to DoublePrecision (64 bit) and a real FPU can perform ExtendedPrecision (80 bit) too. This limitation is caused by the VC-compilers. VisualC can not handle ExtendedPrecision.

Last edited by PeterK; 10 November 2016 at 10:49.
PeterK is offline  
Old 10 November 2016, 10:33   #3
Toni Wilen
WinUAE developer
 
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 45
Posts: 23,672
It gets updated if someone writes assembly wrappers for all required FPU functions..

Multiprecision math libraries are not the answer because they are slower.
Toni Wilen is offline  
 


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Lua interpreter with arbitrary precision math. Thorham Coders. Releases 19 06 January 2020 23:13
Chrome gets emulated. amiga_Forever Retrogaming General Discussion 2 30 November 2014 13:05
Logitech Precision gamepad hasn't worked since 2.3.3 Sigma support.WinUAE 13 20 March 2013 09:29
File timestamps lose precision in shared folders mark_k support.WinUAE 9 06 February 2013 16:25
System you would like to see emulated next Ian Retrogaming General Discussion 18 08 November 2001 08:16

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +2. The time now is 17:00.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Page generated in 0.07214 seconds with 14 queries