ORG   $C000
Entry:
RAM_ADDR	EQU $840	
COUNTREG	EQU $820	
CNTVAL	EQU 4	
CNTVAL1	EQU 5	
  LDS  #RAMEnd+1	
  LDAA #$20
  STAA PPAGE	
  CALL COPY_DATA
  LDAA #$21
  STAA PPAGE	
  CALL CAL_CHKSUM
  LDAA #$22
  STAA PPAGE	
  CALL TEST_CHKSUM
  BRA  $
  ORG PAGE_20Start
COPY_DATA
  LDX  #$8500	
  LDY  #$860	
  LDAA #CNTVAL
  STAA COUNTREG 
B5 LDAA 1,X+ 
  STAA 1,Y+  
  DEC  COUNTREG
  BNE  B5		
  RTC		
	ORG PAGE_21Start
CAL_CHKSUM
  LDAA #CNTVAL		
  STAA COUNTREG
  LDX  #$860	
  CLRA		
B2 ADDA 1,X+ 	
  DEC  COUNTREG
  BNE  B2		
  NEGA		
  STAA 0,X	
  RTC		
	ORG PAGE_22Start
TEST_CHKSUM
  BSET DDRB,%11111111
  LDAA #CNTVAL+1
  STAA COUNTREG
  LDX  #$860 
  CLRA		
B3 ADDA 1,X+ 	
  DEC  COUNTREG
  BNE  B3		
  CMPA #0		
  BEQ  G_1	
  LDAA #'B'	
  STAA PORTB	
  RTC
G_1 LDAA #'G'	
  STAA PORTB	
  RTC
	ORG $8500
MYBYTE FCB $25, $62, $3F, $52, $00