From: fbkotler@nospicedham.myfairpoint.net   
      
   On 08/06/2021 01:11 PM, R.Wieser wrote:   
   > Moderator, Frank : I'm not sure if questions about the x87 FPU are permitted   
   > here.  If not than please just discard.  If they are than please remove this   
   > line. :-)   
      
   Hi Rudy,   
   Consider the line removed.   
   I think x87 is on topic. If necessary, I so rule it. :)   
   I don't know the answer, though...   
   Best.   
   Frank   
   >   
   > Hello all,   
   >   
   > I've just been writing some basic code to parse a simple float, and realized   
   > that I had no idea how to check if the x87 FPU was empty after I was done -   
   > as a simple measure to check if my code cleaned up correctly.   
   >   
   > I've been looking at using the ST bits in the FPU status word, but had to   
   > find that they (unexpectedly) didn't end at zero after I done my thing :   
   >   
   > minimal example:   
   >   
   > fld1    ;Load   
   > fld1   
   >   
   > fstp st(2)   ;Swap ST(0) and ST(1) <-- this is the culprit   
   >   
   > fstp st(0)    ;Discard   
   > fstp st(0)   
   >   
   > At this point all the ST bits are set, indicating a minus one, not zero.   
   >   
   > My questions at this point are:   
   >   
   > 1) Have I done anything wrong in the above ?   I don't think so, but "you   
   > never know" ....   
   >   
   > 2) How do I, for debugging purposes, check the FPU stack ?   
   >   
   > Regards,   
   > Rudy Wieser   
   >   
   >   
      
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