anchor.diff:  
   (defstruct encoding inst (spec 0) rd rs rt (imm 0) (fixed 0) fs ft fd (type 0) func)
   
  -;;
   ;; encode instruction
  -;;
   
   (defun encode-ee-instruction (stream instruction)
     (let ((instruction-info (gethash (first instruction) *mips-instructions*)))
  
positive.code: (make-ee-instructions (make-encoding :spec #b010001 :fixed 0 :rt 16 :fs 11 :inst 21 :type 10 :func #'fpu-type3) 
                        '((mfc1 #b00000) (mtc1 #b00100)))
  
  ;;
  ;; cop-0 instructions
  ;;
  
  (make-ee-instructions (make-encoding :spec #b010000 :fixed #x1000000 :inst 16 :type 3 :func #'inst-type3) 
                        '((bc0f #b00000) (bc0fl #b00010) (bc0t #b00001) (bc0tl #b00011)))
  
negative.code: (def-inst-type fpu-type2 ((fd fs))) 
  (def-inst-type fpu-type3 ((rt fs))) 
  
  
  ;; Registers all instructions 
  
  (make-ee-instructions (make-encoding :inst 26 :rs 16 :rt 21 :imm 0 :type 0 :func #'inst-type0)
                        '((addi #b001000) (addiu #b001001) (andi #b001100) (daddi #b011000) (daddiu #b011001)
                          (ori #b001101) (slti #b001010) (sltiu #b001011) (xori   #b001110)
                          (lb  #b100000) (lbu #b100100) (ld  #b110111) (ldl #b011010) (ldr #b011011)
                          (lwl #b100010) (lh  #b100001) (lhu #b100101) (lw  #b100011) (lq  #b011110)
                          (lwl #b100010) (lwr #b100110) (lwu #b100111) (sb  #b101000) (sd  #b111111) 
                          (sdl #b101100) (sdr #b101101) (sh  #b101001) (sw  #b101011) (swl #b101010) 
                          (swr #b101110) (sq  #b011111)))
  
  (make-ee-instructions (make-encoding :inst 26 :rs 21 :rt 16 :imm 0 :type 0 :func #'inst-type0)
                        '((beq  #b000100) (beql #b000100) (bne  #b000101) (bnel #b010101)))
  