Add   Code         Mnemonics                      Description
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8FC4  		   10 		ORG  &H8FC4	; Initial address
8FC4  CD 7E 00	   20 		CALL &H72	; Change to screen 2
8FC7  21 00 90	   30        	LD   HL,&H9000	; RAM address (images already mixed)
8FCA  01 00 18	   40 		LD   BC,&H1800	; Size of the block
8FCD  11 00 00	   50 		LD   DE,0	; VRAM address (pattern)
8FD0  CD 5C 00	   60 		CALL &H5C	; Write RAM block to VRAM
8FD3  21 00 A8	   70 		LD   HL,&HA800	; RAM address (images already mixed)
8FD6  01 00 18	   80 		LD   BC,&H1800	; Size of the block
8FD9  11 00 20	   90 		LD   DE,&H2000	; VRAM address (color)
8FDC  CD 5C 00	  100 		CALL &H5C	; Write RAM block to VRAM
8FDF  21 00 C0	  110 INICIO:	LD   HL,&HC000	; RAM address (map A)
8FE2  01 00 03	  120 		LD   BC,&H300	; Size of the block
8FE5  11 00 18	  130 		LD   DE,&H1800 	; VRAM address (name table)
8FE8  CD 5C 00	  140 		CALL &H5C	; Write RAM block to VRAM
8FEB  21 00 C3	  150 		LD   HL,&HC300	; RAM address (map B)
8FEE  01 00 03	  160 		LD   BC,&H300	; Size of the block
8FF1  11 00 18	  170 		LD   DE,&H1800	; VRAM address (name table)
8FF4  CD 5C 00	  180 		CALL &H5C	; Write RAM block to VRAM
8FF7  CD 9C 00	  190 		CALL &H9C	; Check keyboard
8FFA  28 E3	  200 		JR   Z,INICIO	; if key NOT pressed go to INICIO
8FFC  CD 78 00	  210 		CALL &H6C	; Change to screen 0
8FFF  C9	  220 		RET 		; Return to Basic

First it copies images A and B already mixed to pattern/color tables.
Then, the program alternates images on screen.

Created by Marcelo Silveira
http://marmsx.msxall.com
