;
;
; PRINT SIZE OF A DISK FILE ARGUMENT IN K BYTES.
;
; ROBERT A. VAN VALZAH
;
; 7/16/77
;
*
*
***************************************************************
*
*	CP/M ASSEMBLER LIBRARY PROCEDURES
*
*	INITIALIZATION OF TRANSIENT PROGRAM
*
*	FILE NAME:	THEAD.LIB
*
*	7/16/77
*
*
*	THIS LIBRARY CAN BE USED TO SET UP A STANDARD
*  CP/M PROGRAM.  TO USE, TYPE THE PROGRAM HEADER AND 
*  PROGRAM CONSTANTS (EQUATES), THEN READ IN THE LIBRARY.
*  TO RETURN TO CP/M EXECUTE A JUMP TO EXIT.
*  USERS MAIN PROGRAM MUST BE LABLED MAIN (OR CHANGE JMP)
*  STACK SIZE IS SET TO 64 BYTES.
*
* 
*	BDOS I/O EQUATES
*
INCON	EQU	1	;READ CONSOLE FUNCTION NO.
OUTCON	EQU	2	;WRITE CONSOLE FUNCTION NO.
INTAPE	EQU	3	;INPUT FROM TAPE READER FUNCTION NO.
OUTTAPE	EQU	4	;OUTPUT TO PUNCH FUNCTION NO.
OUTBUF	EQU	9	;OUTPUT STRING TERMINATED BY $
INBUF	EQU	10	;INPUT BUFFER FUNCTION NO.
BDOS	EQU	5	;BDOS ENTRY POINT
*
*	CONTROL CHARACTERS
*
CR	EQU	0DH	;CARRIAGE RETURN
LF	EQU	0AH	;LINE FEED
CNTRL	EQU	-40H	;CONTROL KEY OFFSET (I.E.  CNTRL+'C')
*
*	EXECUTION
*
	ORG	100H
START:	LXI	H,0
	DAD	SP
	SHLD	OLDSP	;SAVE CP/M'S STACK POINTER
	LXI	SP,STKTOP
	JMP	MAIN
*
*
*	RETURN TO OPERATING SYSTEM
EXIT:	LHLD	OLDSP	;RETURN CP/M'S STACK POINTER
	SPHL
	RET		;RETURN TO SYSTEM
*
*	STACKS
*
OLDSP	DS	2	;RESERVED FOR SYSTEM STACK POINTER
STACK	DS	64	;SPACE FOR USER STACK
STKTOP	EQU	$	;STACK WORKS UP FROM HERE
*
*			END THEAD.LIB
***************************************************************
*
*
*
*
***************************************************************
*
*	CP/M ASSEMBLER LIBRARY PROCEDURES
*
*	DISK I/O EQUATES THRU CP/M
*
*	FILE NAME DISKIOEQ.LIB
*
*	7/16/77
*
*
BUFF	EQU	0080H	;DEFAULT DISK I/O BUFFER
*
*	FILE CONTROL BLOCK DEFINITION AND SUB-DEFINITIONS
*
FCB	EQU	005CH	;DEFAULT FILE CONTROL BLOCK
*
FCBDN	EQU	FCB+0	;DISK NAME, 0=LOGGED IN DISK, 1=A, 2=B
FCBFN	EQU	FCB+1	;FILE NAME (8 CHARACTERS)
FCBFT	EQU	FCB+9	;FILE TYPE (3 CHARACTERS)
FCBEX	EQU	FCB+12	;FILE EXTENT, 0=FIRST 16K, 1=NEXT 16K
FCBRC	EQU	FCB+15	;RECORD COUNT, 80H=FULL EXTENT
FCBNR	EQU	FCB+32	;NEXT RECORD TO BE READ
*
*	BDOS FUNCTION NUMBER EQUATES
*
OPENFF	EQU	15	;OPEN FILE FUNCTION, 255=NOT FOUND
CLOSFF	EQU	16	;CLOSE FILE FUNCTION, 255=NOT FOUND
SRCHF	EQU	17	;SEARCH FOR FILE, 255=NO MATCH
SRCHN	EQU	18	;SEARCH FOR NEXT OCCURRENCE
DELTFF	EQU	19	;DELETE FILE FUNCTION
READRF	EQU	20	;READ NEXT RECORD FUNCTION, 0=READ OK,
			;1=READ PAST END OF FILE,
			;2=READING UNWRITTEN DATA IN RANDOM
			;ACCESS
WRITRF	EQU	21	;WRITE RECORD FUNCTION, 0=WRITE OK,
			;1=ERROR IN EXTENDING FILE,
			;2=NO MORE DISK DATA SPACE (>240K)
			;255=NO MORE DIRECTORY SPACE
MAKEFF	EQU	22	;MAKE FILE FUNCTION, 255=NO DIR. SPACE
*
*
*			END DISKIOEQ.LIB
***************************************************************
*
*
;
; MESSAGES
;
LENMES:	DB	'FILE LENGTH: $'
KMES:	DB	'K$'
NOFILM:	DB	'NO SUCH FILE$'
;
MAIN:
	MVI	B,0	;CLEAR SIZE SUM REG
OPEN:
	PUSH	B	;SAVE SUM SO FAR
	LXI	D,FCB	;OPEN AN EXTENT OF THE FILE
	MVI	C,OPENFF
	CALL	BDOS
	POP	B	;GET SUM SO FAR BACK
	CPI	255	;ABLE TO FIND THAT FILE?
	JZ	NOTHER	;NOPE - GIVE ERROR AND EXIT
;
;	FCBRC NOW CONTAINS THE NUMBER OF 128 BYTE RECORDS
;	IN THIS EXTENT OF THE FILE.  THUS, DIVIDING BY 8
;	WE CAN GET THE EXTENT LENGTH IN K BYTES.  BUT THE
;	DISK IS ALLOCATED IN 1K CHUNKS, SO A LENGTH OF 4.5K
;	BYTES REALLY HAS 5K BYTES ALLOCATED FOR IT.
;	THEREFORE, WE MUST ROUND UP TO GET THE TRUE AMMOUNT
;	OF DISK SPACE ALLOCATED FOR A FILE.
;
	LDA	FCBRC	;GET RECORD COUNT
	ADI	0000$0111B	;CAUSE CARRY INTO BIT 3 IF
			;LENGTH IS NOT AN EVEN K (ROUND UP).
	ANI	1111$1000B	;REMOVE ANY FRACTION LEFT
	RRC		;DIVIDE RESULT BY 8
	RRC
	RRC
	ADD	B	;ADD TO OLD SUM
	MOV	B,A	;UPDATE NEW SUM
	LDA	FCBEX	;PREPARE TO OPEN NEXT EXTENT IF THIS
	INR	A	;ONE IS FULL
	STA	FCBEX
	LDA	FCBRC	;EXTENT IS FULL IF RC=128
	CPI	128
	JZ	OPEN	;IS FULL - OPEN AND ADD NEXT EXTENT
;
;	REACHED LAST EXTENT, FILE LENGTH IN K BYTES IN IN B.
;
	PUSH	B	;SAVE LENGTH
	LXI	D,LENMES	;PRINT "FILE LENGTH: "
	MVI	C,OUTBUF
	CALL	BDOS
	POP	B	;GET LENGTH BACK
	MOV	A,B	;LENGTH -> A
	CALL	DECA	;PRINT A AS A NUMBER 0 - 255
	LXI	D,KMES	;PRINT "K"
	JMP	PRARET	;PRINT AND RETURN
NOTHER:			;COMES HERE IF FILE CAN'T BE FOUND
	LXI	D,NOFILM
PRARET:			;PRINT MESSAGE AT DE AND EXIT
	MVI	C,OUTBUF
	CALL	BDOS
	JMP	EXIT
;
;	DECA PRINTS THE NUMBER IN THE A REG AS A DECIMAL
;	NUMBER 0 - 255.  CLOBBERS A AND E.
;
DECA:
	MVI	E,-1 AND 255	;INITIALIZE QUOTITENT
;
;	THIS LOOP DIVIDES THE A REG BY 10 THRU MULTIPLE
;	SUBTRACTION.  QUOTIENT IS LEFT IN E REG,
;	REMAINDER-10 IS LEFT IN A.
;
LOOP:
	INR	E	;ADD ONE TO QUOTIENT FOR EACH SUBTRACT
	SUI	10
	JNC	LOOP	;HAVEN'T UNDERFLOWED YET
;
	ADI	'0' + 10	;CONVERT REMAINDER TO ASCII
	PUSH	PSW	;PUT THIS DIGIT ON THE STACK
	MOV	A,E	;GET REMAINDER -> A
	ORA	A	;DONE WITH ALL DIGITS?
	CNZ	DECA	;NO - DO THIS AGAIN WITH THE REMAINDER
;
;	THE ASCII NUMBER IS NOW UP ON THE STACK, MSD FIRST
;	TO COME OFF.  BDOS WILL PROBABLY RETURN HERE.
;
	POP	PSW
	MOV	E,A
	MVI	C,OUTCON
	JMP	BDOS
;
	END	ENTRY