title: logical shift and rotate
body: <p>i have a problem here understand this part of the code. can anyone explain me how this two orders (lsl and rol)works?</p>
  
  <p>main:       </p>
  
  <pre><code>        clr r0
          clr r22 ; 
          LDI ZL,LOW(AEMS)
          ldi zh,HIGH(AEMS)
          lsl zl
          rol zh
          mov r22,zl
  </code></pre>
  
  <p>aems contains : 
  AEMS:.db $74,$91 ;7491
  .db $76,$28 ;7628</p>