DrawSpriteXxY

;===========================================================
DrawSpriteXxY:
;===========================================================
;Inputs:
;     A is the method:
;        0=Overwrite
;        1=AND
;        2=XOR
;        3=OR
;        4=Swap
;        5=Erase
;     B is the width (in bytes)
;     C is the height (in pixels)
;     DE points to the sprite data
;     HL points to the output location
;Outputs:
;     HL is A*12 larger (next sprite down?)
;     DE points to the next byte after the sprite data
;     A is 0
;     B is not changed
;     C is 12-B
;===========================================================
          push af             ;F5
          ld a,c              ;79
          di                  ;F3
          ex af,af'           ;08
          ld a,12             ;3E0C
          sub b               ;90
          ld c,a              ;4F
          pop af              ;F1
OverwriteXxY:
          or a                ;B7
          jr nz,ANDXxY        ;2010
            ex af,af'         ;08
              ex de,hl        ;EB
              push bc         ;C5
                ldi           ;EDA1
                inc bc        ;03
                djnz $-3      ;10FB
              ex de,hl        ;EB
              add hl,bc       ;09
              pop bc          ;C1
              dec a           ;3D
              jr nz,$-11      ;20F3
            ret               ;C9
ANDXxY:
          dec a               ;3D
          jr nz,XORXxY        ;2011
            ex af,af'           ;08
              push bc             ;C5
              push af             ;F5
                ld a,(de)           ;1A
                and (hl)            ;A6
                ld (hl),a           ;77
                inc de              ;13
                inc hl              ;23
                djnz $-5            ;10F9
              add hl,bc           ;09
              pop af              ;F1
              pop bc              ;C1
              dec a               ;3D
              jr nz,$-13          ;20F1
            ret                 ;C9
XORXxY:
          dec a               ;3D
          jr nz,ORXxY         ;2011
            ex af,af'           ;08
              push bc             ;C5
              push af             ;F5
                ld a,(de)           ;1A
                xor (hl)            ;AE
                ld (hl),a           ;77
                inc de              ;13
                inc hl              ;23
                djnz $-5            ;10F9
              add hl,bc           ;09
              pop af              ;F1
              pop bc              ;C1
              dec a               ;3D
              jr nz,$-13          ;20F1
            ret                 ;C9
ORXxY:
          dec a               ;3D
          jr nz,SwapXxY       ;2011
            ex af,af'           ;08
              push bc             ;C5
              push af             ;F5
                ld a,(de)           ;1A
                or (hl)             ;B6
                ld (hl),a           ;77
                inc de              ;13
                inc hl              ;23
                djnz $-5            ;10F9
            add hl,bc           ;09
            pop af              ;F1
            pop bc              ;C1
            dec a               ;3D
            jr nz,$-13          ;20F1
            ret                 ;C9
SwapXxY:
          dec a               ;3D
          jr nz,EraseXxY      ;2011
            ex af,af'           ;08
            ld c,12             ;0E0C
              push bc             ;C5
              push af             ;F5
                ld a,(de)           ;1A
                ldi                 ;EDA0
                dec hl              ;2B
                ld (hl),a           ;77
                inc hl              ;23
                djnz $-6            ;10F8
              add hl,bc           ;09
              pop af              ;F1
              pop bc              ;C1
              dec a               ;3D
              jr nz,$-14          ;20F0
            ret                 ;C9
EraseXxY:
            ex af,af'           ;08
              push bc             ;C5
              push af             ;F5
                ld a,(de)           ;1A
                cpl                 ;2F
                and (hl)            ;A6
                ld (hl),a           ;77
                inc de              ;13
                inc hl              ;23
                djnz $-6            ;10F8
              add hl,bc           ;09
              pop af              ;F1
              pop bc              ;C1
              dec a               ;3D
              jr nz,$-14          ;20F0
            ret                 ;C9