LDA - Load Accumulator from Memory ;flags(N,Z)
LDA #opr ;A <= opr ;(IMM) 8 bit immediate
LDA opr ;A <= (opr) ;(DIR) 8 bit direct
LDA opr ;A <= (opr) ;(EXT) 16 bit extended
LDA ,X ;A <= (X) ;(IX) indexed no offset
LDA opr,X ;A <= (opr + X) ;(IX1) indexed w/8 bit offset
LDA opr,X ;A <= (opr + X) ;(IX2) indexed w/16 bit offset