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compiling pcl on Coral Common Lisp

   From: Kevin_Crowston@XV.MIT.EDU
   Date: 17 Aug 89 14:52:40 EDT
   Sender: Kevin_Crowston@XV.MIT.EDU

   Quite some time ago, I mentioned I had problems compiling
   PCL on a Mac with an accelerator board.  Through the kindness
   of TSI, the board manufacturer, I have discovered that
   Allegro, when running on a 68020, assumes the existance of
   an FPU chip.  Putting in the FPU chip solves the problem.

this isn't quite right.  Mac Allegro never assumed that 68020 implied an
FPU chip.  Rather, it assumes that unimplemented instruction traps
get processed correctly.  On a machine without an FPU, executing an FPU
instruction should cause an unimplemented instruction trap, which Lisp
than catches, redirecting things to SANE.  Unfortunately, some accellerator
board manufactures play with the exception handling so that unimplemented
instruction traps don't occur  properly.

In any case, putting in an FPU chip solves the problem.