+
+(defun prefixed-fixnum-string (num pchar len)
+ "Outputs a string of LEN chars with the initial character being
+PCHAR. Leading zeros are printed."
+ (declare (optimize (speed 3) (safety 0) (space 0))
+ (type fixnum v len))
+ (let ((zero-code (char-code #\0))
+ (result (make-string len :initial-element #\0))
+ (pos (1- len)))
+ (declare (fixnum zero-code pos)
+ (simple-string result))
+ (do* ((val num (floor (/ val 10)))
+ (mod (nth-value 1 (floor val 10))
+ (nth-value 1 (floor val 10))))
+ ((or (zerop val) (minusp pos)))
+ (declare (fixnum val mod))
+ (setf (schar result pos) (code-char (+ zero-code mod)))
+ (decf pos))
+ (when pchar
+ (setf (schar result 0) pchar))
+ result))