(defvar BN_DIGIT_SIZE 16)
(defvar #:system:NO_BYTE_IN_DIGIT (div BN_DIGIT_SIZE 8))

(defmacro defC (name ltype type)
   (let ( (Cname (concat "_" name)) (Lname (implode (explode name))) )
      `(progn
         (defextern ,Cname
            ,(nsubst 'string 'N (nsubst 'fix 'I (subst 't 'Ad ltype)))
            ,(cassq type '((N . string) (I . t) (Ad . t))) )
         (synonymq ,Lname ,Cname)
         (remfn ',Cname)
         ',Lname )))

(unless (featurep 'kern)
	(cond ((eq 0 (getglobal "_BnAlloc"))
	    (let ( (l #:system:path) f )
	      (while (and l (null (probefile
				   (setq f (catenate (car l) "kern.o")))))
		(nextl l))
	      (ifn l
		   (error 'kern "Je ne trouve pas kern.o dans le path" ())
		   (cload f) ))))
	(add-feature 'kern) )

    '(defC "BnAlloc"                     (I)                 N)
    '(defC "BnCreate"                    (Ad I)              N)
    '(defC "BnFree"                      (N)                 Fix)
    '(defC "BnGetType"                   (N)                 Ad)
    '(defC "BnSetType"                   (N Ad)              U)
    '(defC "BnGetSize"                   (N)                 I)
    (defC "BnSetToZero"                 (N I I)             U)
    (defC "BnAssign"                    (N I N I I)         U)
    (defC "BnSetDigit"                  (N I Fix)           U)
    (defC "BnGetDigit"                  (N I)               Fix)
    (defC "BnNumDigits"                 (N I I)             I)
    (defC "BnNumLeadingZeroBitsInDigit" (N I)               Fix)
    (defC "BnDoesDigitFitInWord"        (N I)               Fix)
    (defC "BnIsDigitZero"               (N I)               Fix)
    (defC "BnIsDigitNormalized"         (N I)               Fix)
    (defC "BnIsDigitOdd"                (N I)               Fix)
    (defC "BnCompareDigits"             (N I N I)           Fix)
    (defC "BnComplement"                (N I I)             U)
    (defC "BnAndDigits"                 (N I N I)           U)
    (defC "BnOrDigits"                  (N I N I)           U)
    (defC "BnXorDigits"                 (N I N I)           U)
    (defC "BnShiftLeft"                 (N I I N I Fix)     U)
    (defC "BnShiftRight"                (N I I N I fix)     U)
    (defC "BnAddCarry"                  (N I I Fix)         Fix)
    (defC "BnAdd"                       (N I I N I I Fix)   Fix)
    (defC "BnSubtractBorrow"            (N I I Fix)         Fix)
    (defC "BnSubtract"                  (N I I N I I Fix)   Fix)
    (defC "BnMultiplyDigit"             (N I I N I I N I)   Fix)
    (defC "BnDivideDigit"               (N I N I N I I N I) U)
)

(defun BnAlloc (i)
  (makestring (mul #:system:NO_BYTE_IN_DIGIT i) 0))

(defun BnCreate (Ad i)
  (let ( (n (makestring (mul #:system:NO_BYTE_IN_DIGIT i) 0)) )
    (typestring n Ad)
    n ))

(defun BnFree (n))

(defun BnGetType (n)
   (typestring n))

(defun BnSetType (n Ad)
   (typestring n Ad))

(defun BnGetSize (n)
  (div (slen n) #:system:NO_BYTE_IN_DIGIT))

(defvar #:KerN:tampon (BnCreate 'n 2))
(defun #:N:prin (s)
   (let ( cnt )
      (with ( (obase 16) )
         (for (i (sub1 (BnGetSize s)) -1 0)
            (BnAssign #:KerN:tampon 0 s i 1)
            (setq cnt 0)
            (while (< cnt BN_DIGIT_SIZE)
               (BnShiftLeft #:KerN:tampon 0 1 #:KerN:tampon 1 4)
               (prin (BnGetDigit #:KerN:tampon 1))
               (incr cnt 4) )))))