gforth/float.fs - diff

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-version 1.26, 1999/05/06 21:33:32
+version 1.27, 1999/05/15 20:00:20
  Line 193  IS interpreter-notfound
  \ : facosh   fdup fdup f* 1.0e0 f- fsqrt f+ fln ;
  \ : fasinh   fdup fdup f* 1.0e0 f+ fsqrt f/ fatanh ;
- \ !! factor out parts
+ : f~abs ( r1 r2 r3 -- flag ) \ gforth
- : f~ ( f1 f2 f3 -- flag ) \ float-ext
+     \G Approximate equality with absolute error: |r1-r2|<r3.
+     frot frot f- fabs fswap f< ;
+ : f~rel ( r1 r2 r3 -- flag ) \ gforth
+     \G Approximate equality with relative error: |r1-r2|<r3*|r1+r2|.
+         frot frot fover fabs fover fabs f+ frot frot
+         f- fabs frot frot f* f< ;
+ : f~ ( r1 r2 r3 -- flag ) \ float-ext
+     \G ANS Forth medley: r3>0: @code{f~abs}; r3=0: r1=r2; r3<0: @code{fnegate f~abs}.
      fdup f0=
      IF
-         fdrop f= EXIT
+         fdrop f=  \ !! this does not work, because 0=-0 with f= on Linux-Intel
+                   \ the standard says they should compare unequal
+                   \ the comparison should be done with COMPARE
+         EXIT
      THEN
      fdup f0>
      IF
-         frot frot f- fabs fswap
+         f~abs
      ELSE
-         fnegate frot frot fover fabs fover fabs f+ frot frot
+         fnegate f~rel
-         f- fabs frot frot f*
+     THEN ;
-     THEN
-     f< ;
  : f.s ( -- ) \ gforth f-dot-s
      \G Display the number of items on the floating-point stack,