* @const scaf_piece *mu@ = scaled approximation to @1/l@
* @size_t npiece@ = number of pieces in @l@
* @unsigned piecewd@ = nominal width of a piece in bits
- * @scaf_piece *scratch@ = @3*npiece + 1@ scratch pieces
+ * @scaf_piece *scratch@ = @3*npiece@ scratch pieces
*
* Returns: ---
*