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Bignum bug?

    Date: 21 September 1980 20:44-EDT
    From: Fred W. Helenius <FH at MIT-MC>
    If you compile the following function (which is intended to add two
    .  .  .
    (defun add-rats (a b)
	   (let (((c . d) a)
		 ((e . f) b))
		(let ((hcf (gcd d f)))
		     (cons (plus (times c (quotient f hcf))
				 (times e (quotient d hcf)))
			   (times (quotient d hcf) f)))))
    (setq exp
	  '(apply 'add-rats '((716087101460491 . 1041496283283456)
			      (103334765625 . 197568495616))))
    .  .  .
    I suppose this is a bug.  The function works fine in the interpreter,
    and compiled for most arguments.  For your convenience, the function
    definition, the result of its compilation, and the definition of exp
    may be found in FH;BUG DEFN, BUG FASL, and BUG EXP, respectively.
I took the liberty of changing your BUG EXP file so that the bug would be
visible in LISP as well as MACSYMA (i.e., I added the necessary decimal
point after the numbers).  This result is actually due to a bug in LISP,
and I've just patched it (GCD was clobbering a random register).