Please read this page from the main YASEP interface
MOV : MOVe
This instruction copies either
 -  a register's content (si4) (short register
        or extended register forms)
 
-  a 4-bit immediate value (short immediate or extended immediate forms)
 
-  a 16-bit value (long immediate form with YASEP16)
 
-  a 20-bit value (long immediate form with YASEP32)
to the destination register (snd).