From: stephen@vfxforth.com   
      
   On 6 Jul 2025 at 04:52:37 CEST, "dxf"  wrote:   
      
   > On 5/07/2025 6:49 pm, Anton Ertl wrote:   
   >> dxf  writes:   
   >> [8 stack items on the FP stack]   
   >>> Puzzling because of a thread here not long ago in which scientific users   
   >>> appear to suggest the opposite.  Such concerns have apparently been around   
   >>> a long time:   
   >>>   
   >>> https://groups.google.com/g/comp.lang.forth/c/CApt6AiFkxo/m/wwZmc_Tr1PcJ   
   >>   
   >> I have read through the thread.  It's unclear to me which scientific   
   >> users you have in mind.  My impression is that 8 stack items was   
   >> deemed sufficient by many, and preferable (on 387) for efficiency   
   >> reasons.   
   >   
   > AFAICS both Skip Carter (proponent) and Julian Noble were suggesting the   
   > 6 level minimum were inadequate.  A similar sentiment was expressed here   
   > only several months ago.  AFAIK all major forths supporting x87 hardware   
   > offer software stack options.   
   >   
   >> Certainly, of the two points this thread is about, there was a   
   >> Forth200x proposal for standardizing a separate FP stack, and this   
   >> proposal was accepted.  There was no proposal for increasing the   
   >> minimum size of the FP stack; Forth-2012 still says:   
   >>   
   >> |The size of a floating-point stack shall be at least 6 items.   
   >   
   > Only because nothing further was heard.  What became of the review   
   > Elizabeth announced I've no idea.   
   >   
   >> One interesting aspect is that VFX 5.x finally includes an FP package   
   >> by default, and it started by including an SSE2-based FP package which   
   >> supports a deep FP stack.  However, MPE received customer complaints   
   >> about the lower number of significant digits in SSE2 (binary64)   
   >> vs. 387 (80-bit FP values), so they switched the default to the   
   >> 387-based FP package that only has 8 FP stack items.  Apparently no   
   >> MPE customer complains about that limitation.   
   >> ...   
   >   
   > AFAIK x87 hardware stack was always MPE's main and best supported FP   
   > package.  As for SSE2 it wouldn't exist if industry didn't consider   
   > double-precision adequate.  My impression of MPE's SSE2 implementation   
   > is that it's 'a work in progress'.  The basic precision is there but   
   > transcendentals appear to be limited to single-precision.  That'd be   
   > the reason I'd stick with MPE's x87 package.  Other reason is it's now   
   > quite difficult and error-prone to switch FP packages as it involves   
   > rebuilding the system.  The old scheme was simpler and idiot-proof.   
      
   You do not have to rebuild the system to switch. Just read the manual.   
      
   "The old scheme was simpler and idiot-proof." Yes, that's why we   
   did it that way, but a certain "guru" who only does testing kept   
   moaning. If people would prefer us to go back to the old scheme,   
   VFX 6 still has time for changes. The whole idea that compiling   
   one file is improper is very non-Forth, or even anti-Forth.   
      
   I may be getting grumpier as I get older.   
      
   Stephen   
   --   
   Stephen Pelc, stephen@vfxforth.com   
   Wodni & Pelc GmbH   
   Vienna, Austria   
   Tel: +44 (0)7803 903612, +34 649 662 974   
   http://www.vfxforth.com/downloads/VfxCommunity/   
     free VFX Forth downloads   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)