;CHECKSUM ANY CP/M FILE
 0100           	ORG	100H
 0100 C31901    	JMP	START
 0103 434B53554DID	DB	'CKSUM AS OF 7/20/77',0DH,0AH,'$'
                ;INIT LOCAL STACK
 0119 210000    START	LXI	H,0
 011C 39        	DAD	SP
 011D 22F401    	SHLD	STACK
 0120 31F401    	LXI	SP,STACK
                ;PRINT ID MESSAGE
 0123 110301    	LXI	D,ID
 0126 0E09      	MVI	C,PRINT
 0128 CD0500    	CALL	BDOS
                ;OPEN THE FILE
 012B 115C00    	LXI	D,FCB
 012E 0E0F      	MVI	C,OPEN
 0130 CD0500    	CALL	BDOS
 0133 3C        	INR	A
 0134 C25601    	JNZ	LINE
 0137 CD4B01    	CALL	ERXIT
 013A 2B2B46494C	DB	'++FILE NOT FOUND$'
 014B D1        ERXIT	POP	D	;GET MSG
 014C 0E09      	MVI	C,PRINT
 014E CD0500    	CALL	BDOS
 0151 2AF401    EXIT	LHLD	STACK
 0154 F9        	SPHL		;RESTORE STACK
 0155 C9        	RET
                ;OPENED OK
 0156 3E0D      LINE	MVI	A,0DH
 0158 CDC001    	CALL	TYPE
 015B 3E0A      	MVI	A,0AH
 015D CDC001    	CALL	TYPE
 0160 0610      	MVI	B,16	;# OF HEX PER LINE
 0162 C5        LOOP	PUSH	B	;SAVE DIGIT COUNT
 0163 CDCD01    	CALL	FREAD
 0166 B7        	ORA	A
 0167 C27E01    	JNZ	CKERR
 016A 218000    	LXI	H,80H
 016D AF        	XRA	A
 016E 86        CKSLP	ADD	M
 016F 2C        	INR	L
 0170 C26E01    	JNZ	CKSLP
 0173 CDA301    	CALL	XOB
 0176 C1        	POP	B
 0177 05        	DCR	B
 0178 C26201    	JNZ	LOOP
 017B C35601    	JMP	LINE
                ;NON-ZERO DISK RETURN CODE
 017E 3D        CKERR	DCR	A
 017F CA9801    	JZ	EOF
 0182 CD4B01    	CALL	ERXIT
 0185 2A2B2B4449	DB	'*++DISK READ ERROR$'
 0198 CD4B01    EOF	CALL	ERXIT
 019B 0D0A2B2B45	DB	0DH,0AH,'++EOF$'
 01A3 F5        XOB	PUSH	PSW
 01A4 1F        	RAR
 01A5 1F        	RAR
 01A6 1F        	RAR
 01A7 1F        	RAR
 01A8 CDB501    	CALL	NIBBL
 01AB F1        	POP	PSW
 01AC CDB501    	CALL	NIBBL
 01AF 3E20      	MVI	A,' '
 01B1 CDC001    	CALL	TYPE
 01B4 C9        	RET
 01B5 E60F      NIBBL	ANI	0FH
 01B7 FE0A      	CPI	10
 01B9 DABE01    	JC	ISNUM
 01BC C607      	ADI	7
 01BE C630      ISNUM	ADI	'0'
 01C0 C5        TYPE	PUSH	B
 01C1 D5        	PUSH	D
 01C2 E5        	PUSH	H
 01C3 5F        	MOV	E,A
 01C4 0E02      	MVI	C,WRCON
 01C6 CD0500    	CALL	BDOS
 01C9 E1        	POP	H
 01CA D1        	POP	D
 01CB C1        	POP	B
 01CC C9        	RET
                ;FILE READ
 01CD 115C00    FREAD	LXI	D,FCB
 01D0 0E14      	MVI	C,READ
 01D2 CD0500    	CALL	BDOS
 01D5 C9        	RET		;PROG SHOULD CHECK STAT
 01D6           	DS	30
 01F4           STACK	DS	2
                ;
                ; BDOS EQUATES (VERSION 3)
                ;
 0001 =         RDCON	EQU	1
 0002 =         WRCON	EQU	2
 0009 =         PRINT	EQU	9
 000F =         OPEN	EQU	15	;0FFH=NOT FOUND
 0010 =         CLOSE	EQU	16	;   "	"
 0011 =         SRCHF	EQU	17	;   "	"
 0012 =         SRCHN	EQU	18	;   "	"
 0013 =         DELT	EQU	19	;NO RET CODE
 0014 =         READ	EQU	20	;0=OK, 1=EOF
 0015 =         WRITE	EQU	21	;0=OK, 1=ERR, 2=?, 0FFH=NO DIR SPC
 0016 =         MAKE	EQU	22	;0FFH=BAD
 0017 =         REN	EQU	23	;0FFH=BAD
 001A =         STDMA	EQU	26
 0005 =         BDOS	EQU	5
 005C =         FCB	EQU	5CH