swap    %d1
    move.l  %d1,%d0
    and.l   #0xff00ff00,%d0 /* |rrrrrggg|00000000|rrrrrggg|00000000| */
    eor.l   %d0, %d1        /* |00000000|gggbbbbb|00000000|gggbbbbb| */
    lsr.l    #8,%d0         /* |00000000|rrrrrggg|00000000|rrrrrggg| */
    move.l  %d0,%d5
    and.l   #0x00f800f8,%d5 /* |00000000|rrrrr000|00000000|rrrrr000| */
    add.l   %d0,%d5         /* |0000000r|rrrr0ggg|0000000r|rrrr0ggg| */
    move.w  %d5,(%a1)
    lsl.l    #1,%d1         /* |0000000g|ggbbbbb0|0000000g|ggbbbbb0| */
    move.w  %d1,(%a1)
    swap    %d5
    swap    %d1
    move.w  %d5,(%a1)
    move.w  %d1,(%a1)