anchor.diff:  ;;; Encodes block using specified huffman tables, returns new pred (DC prediction value)
   ;;; and last code written to stream for padding
   (defun encode-block (block tables pred s)
  -  (declare #.*optimize* (type fixnum pred newpred diff dcpos)
  +  (declare #.*optimize* (type fixnum pred)
              (type (simple-vector *) block))
     (let* ((ehufsi-dc (first (first tables)))
            (ehufco-dc (second (first tables)))
  
positive.code: ;;; to the Independent JPEG Group - colorspace conversion and DCT algorithms were adopted from their sources;
  ;;; to Jeff Dalton for his wise paper "Common Lisp Pitfalls".
  
  (defpackage #:jpeg (:use #:common-lisp))
  (in-package #:jpeg)
  
  (eval-when (compile)
    (export '(encode-image decode-image jpeg-to-bmp)))
  
  (declaim (inline csize write-stuffed quantize get-average zigzag encode-block llm-dct descale crunch colorspace-convert subsample
                   inverse-llm-dct dequantize upsample extend recieve decode-ac decode-dc decode-block izigzag write-bits))
  
negative.code: 
  ;;; Function that maps value into SSSS
  (defun csize (n)
      (declare #.*optimize* (type fixnum n))
      (svref *csize* (plus n 1023)))
  
  ;;; zigzag ordering
  