- (let ((thresh (/ (abs divisor) 2)))
- (cond ((or (> rem thresh)
- (and (= rem thresh) (oddp tru)))
- (if (minusp divisor)
- (values (- tru 1) (+ rem divisor))
- (values (+ tru 1) (- rem divisor))))
- ((let ((-thresh (- thresh)))
- (or (< rem -thresh)
- (and (= rem -thresh) (oddp tru))))
- (if (minusp divisor)
- (values (+ tru 1) (- rem divisor))
- (values (- tru 1) (+ rem divisor))))
- (t (values tru rem)))))))
+ (if (zerop rem)
+ (values tru rem)
+ (let ((thresh (/ (abs divisor) 2)))
+ (cond ((or (> rem thresh)
+ (and (= rem thresh) (oddp tru)))
+ (if (minusp divisor)
+ (values (- tru 1) (+ rem divisor))
+ (values (+ tru 1) (- rem divisor))))
+ ((let ((-thresh (- thresh)))
+ (or (< rem -thresh)
+ (and (= rem -thresh) (oddp tru))))
+ (if (minusp divisor)
+ (values (+ tru 1) (- rem divisor))
+ (values (- tru 1) (+ rem divisor))))
+ (t (values tru rem))))))))