Smooth palette change (S3K)

; How to use:
        jsr (Create_New_Sprite).l
        bne.s   +
        move.l  #Obj_SmoothPalette,(a1)
        move.w  #4,subtype(a1)
        move.l  #Pal_FDZ3_Rain,$30(a1)
        move.w  #Normal_palette_line_3,$34(a1)
        move.w  #16-1,$38(a1)

; =============== S U B R O U T I N E =======================================

Obj_SmoothPalette:
        subq.w  #1,$2E(a0)
        bpl.s   SmoothPalette_Return
        move.w  subtype(a0),$2E(a0)
        movea.l $30(a0),a1          ; palette pointer
        movea.w $34(a0),a2          ; palette ram
        move.w  $38(a0),d6          ; palette size
        jsr (Pal_FadeToPal).l
        bne.s   SmoothPalette_Return
        move.l  #Delete_Current_Sprite,address(a0)

SmoothPalette_Return:
        rts
; ---------------------------------------------------------------------------
; Smooth palette change
; Inputs:
; a1 = current palette
; a2 = current palette line
; d7 = number of colors
; ---------------------------------------------------------------------------

; =============== S U B R O U T I N E =======================================

Pal_FadeToPal:
        tst.b   (Palette_refade_count).w
        bne.s   Pal_FadeToPal_Loop
        move.b  #7,(Palette_refade_count).w

Pal_FadeToPal_Loop:
        moveq   #0,d5
        move.w  (a1)+,d2
        move.w  (a2),d3
        cmp.w   d2,d3
        beq.s   Pal_FadeToPal_Next
        move.w  d2,d0
        move.w  d3,d1
        andi.w  #$E,d0
        andi.w  #$E,d1
        move.w  #2,d4
        cmp.w   d1,d0
        beq.s   ++
        bhi.s   +
        neg.w   d4
+       add.w   d4,d1
+       or.w    d1,d5
        move.w  d2,d0
        move.w  d3,d1
        andi.w  #$E0,d0
        andi.w  #$E0,d1
        move.w  #$20,d4
        cmp.w   d1,d0
        beq.s   ++
        bhi.s   +
        neg.w   d4
+       add.w   d4,d1
+       or.w    d1,d5
        move.w  d2,d0
        move.w  d3,d1
        andi.w  #$E00,d0
        andi.w  #$E00,d1
        move.w  #$200,d4
        cmp.w   d1,d0
        beq.s   ++
        bhi.s   +
        neg.w   d4
+       add.w   d4,d1
+       or.w    d1,d5
        move.w  d5,(a2)

Pal_FadeToPal_Next:
        addq.w  #2,a2
        dbf d7,Pal_FadeToPal_Loop
        subq.b  #1,(Palette_refade_count).w
        rts
; End of function Pal_FadeToPal