RomWBW/Source/Images/d_bp/u15/FINDF.MAC

; PROGRAM:  FINDF
; AUTHOR:  RICHARD CONN
; VERSION:  2.0
; DATE:  18 May 84
; PREVIOUS VERSIONS: 1.1 (25 July 83), 1.0 (24 JULY 83)
;
VERS	EQU	20		;version number
z3env	SET	0f400h

;
;	FINDF searches through all of the known disks for one or more
; files matching the passed file specification.  AFNs (Ambiguous File Names)
; are permitted.  FINDF is invoked by the following command line:
;		FINDF afn,afn,afn,... o
; where "afn" refers to the file sought and "o" is none or more of:
;		S - Include System Files
;

;
; System equates:
;
BOOT	EQU	0000H		;CP/M WARM BOOT JUMP VECTOR
BDOS	EQU	BOOT+05H	;CP/M BDOS CALL JUMP VECTOR
TBUFF	EQU	BOOT+80H	;DISK I/O BUFFER
FCB	EQU	BOOT+5CH	;DEFAULT FILE CONTROL BLOCK
CR	EQU	'M'-'@'		;CTL-M FOR CARRIAGE RETURN
LF	EQU	'J'-'@'		;CTL-J FOR LINE FEED
CTRLC	EQU	'C'-'@'		;ABORT
CTRLS	EQU	'S'-'@'		;PAUSE
ESIZE	EQU	12		;12 BYTES/DIR ENTRY

;
; SYSLIB and Z3LIB Routines
;
	ext	z3init,codend
	ext	cout,crlf,print,padc

;
; Environment Definition
;
	if	z3env ne 0
;
; External ZCPR3 Environment Descriptor
;
	jmp	start
	db	'Z3ENV'	;This is a ZCPR3 Utility
	db	1	;External Environment Descriptor
z3eadr:
	dw	z3env
start:
	lhld	z3eadr	;pt to ZCPR3 environment
;
	else
;
; Internal ZCPR3 Environment Descriptor
;
	MACLIB	Z3BASE.LIB
	MACLIB	SYSENV.LIB
z3eadr:
	jmp	start
	SYSENV
start:
	lxi	h,z3eadr	;pt to ZCPR3 environment
	endif

;
; Start of Program -- Initialize ZCPR3 Environment
;
	call	z3init	;initialize the ZCPR3 Env and the VLIB Env
	LXI	H,0		;SAVE STACK PTR
	DAD	SP
	SHLD	STACK
	CALL	CODEND		;DETERMINE FREE SPACE
	SHLD	FNTAB		;FILE NAME TABLE
	LXI	D,512		;1/2 K SPACE
	DAD	D
	SHLD	SCRATCH		;BEGINNING OF SCRATCH AREA
	SPHL			;AND TOP OF STACK
	CALL	GTBIOS		;GET BIOS JUMP TABLE
	CALL 	HELLO		;SIGN ON MESSAGE
	CALL	HELPCHK		;CHECK FOR AND PRINT HELP MESSAGE
	CALL	OPTCHK		;BUILD FILE NAME TABLE AND PROCESS OPTIONS
	CALL	CRLF		;NEW LINE
	CALL	FIND		;DO THE SEARCHES
	CALL	BYE		;SIGN OFF MESSAGE
RETURN:
	LHLD	STACK		;QUIET RETURN
	SPHL
	RET
;
; ** Main Routines **
;

;
; SAY WHO WE ARE
;
HELLO:
	CALL	PRINT
	DB	'FINDF, Version '
	DB	(VERS/10)+'0','.',(VERS MOD 10)+'0'
	DB	0
	RET
;
;  CHECK FOR HELP REQUEST
;
HELPCHK:
	LDA	FCB+1		;GET 1ST BYTE OF FILENAME
	CPI	'/'		;HELP?
	JZ	HCK1
	CPI	' '		;MAKE SURE IT IS NON-BLANK
	RNZ			;OK - KEEP GOING
;	
; IF NO FILE NAME IS SPECIFIED, ABORT WITH NOTICE
;
HCK1:
	CALL 	PRINT
	db	cr,lf,'Syntax:'
	DB	CR,LF,'   FINDF afn,afn,afn,... o'
	db	cr,lf,'Options:'
	DB	CR,LF,'   S - Include System Files'
	DB	0
	JMP	RETURN
;
; CHECKS FOR S OPTION IN COMMAND LINE AND EXTRACTS FILE NAMES INTO TABLE
;
OPTCHK:
	XRA	A	;TURN OFF FLAGS
	STA	SYSTEM	;NO SYSTEM FILES
	STA	FFLAG	;NO FILES FOUND
	STA	ECOUNT	;NO ENTRIES
	STA	FNCOUNT	;NO FILE NAMES
	LHLD	FNTAB	;PT TO TABLE
	XCHG		;... IN DE
	LXI	H,TBUFF+1	;SCAN THRU TBUFF, BUILDING A FILE NAME TABLE
	CALL	SBLANK	;SKIP BLANKS
FNLOOP:
	PUSH	D	;SAVE TABLE PTR
	CALL	GETFN	;EXTRACT FILE NAME
	POP	D
	PUSH	H
	LXI	H,11	;PT TO NEXT TABLE ENTRY
	DAD	D
	XCHG
	POP	H
	LDA	FNCOUNT	;INCREMENT COUNT
	INR	A
	STA	FNCOUNT
	MOV	A,M	;GET TERMINATING CHAR
	INX	H	;PT TO NEXT
	CPI	','	;ANOTHER FOLLOWS?
	JZ	FNLOOP
	DCX	H	;POINT BACK TO DELIM
	CALL	SBLANK	;SKIP TO NON-BLANK
OPTCK1:
	MOV	A,M	;GET OPTION
	CALL	DELCHK	;DONE IF DELIM
	RZ
	CPI	'S'	;SYSTEM?
	JZ	OPTCKS
	CALL	PRINT
	DB	CR,LF,'Invalid Option -- ',0
	MOV	A,M
	CALL	COUT
	JMP	HCK1
OPTCKS:
	MVI	A,0FFH	;SET FLAG
	STA	SYSTEM
	INX	H
	JMP	OPTCK1
GETFN:
	PUSH	D	;FILL TARGET FCB
	MVI	B,11	;11 BYTES
	MVI	A,' '	;SPACE FILL
GETFN0:
	STAX	D	;PUT SPACE
	INX	D
	DCR	B
	JNZ	GETFN0
	POP	D	;PT TO ENTRY AGAIN
	CALL	SCANCOL	;SCAN FOR COLON
	MVI	B,8	;8 CHARS MAX
	CALL	GETFN1	;GET AND FILL ENTRY
	MOV	A,M	;GET CHAR
	CPI	'.'	;DELIM?
	RNZ		;DONE
	INX	H	;PT TO AFTER PERIOD
	MVI	B,3	;3 CHARS MAX AND DO IT AGAIN
GETFN1:
	MOV	A,M	;GET CHAR
	CPI	'.'	;END OF FIELD?
	JZ	GETFN3
	CALL	DELCHK	;CHECK DELIMITER
	RZ
	CPI	'*'	;WILD?
	JZ	GETFNQ
	STAX	D	;STORE CHAR
	INX	H	;PT TO NEXT
	INX	D
	DCR	B	;COUNT DOWN
	JNZ	GETFN1
GETFN2:
	MOV	A,M	;FLUSH CHARS TO DELIM
	CALL	DELCHK	;CHECK FOR DELIMITER
	RZ
	INX	H	;PT TO NEXT
	JMP	GETFN2
GETFN3:
	INX	D	;PT TO AFTER FIELD
	DCR	B	;COUNT DOWN
	JNZ	GETFN3
	RET
GETFNQ:
	MVI	A,'?'	;FILL WITH QUESTION MARKS
	STAX	D
	INX	D
	DCR	B
	JNZ	GETFNQ
	JMP	GETFN2	;SKIP TO DELIM
DELCHK:
	ORA	A	;END OF LINE?
	RZ
	CPI	'.'	;END OF FIELD?
	RZ
	CPI	','	;END OF ENTRY?
	RZ
	CPI	' '
	RET
SBLANK:
	MOV	A,M	;SKIP TO NON-BLANK
	CPI	' '
	RNZ
	INX	H
	JMP	SBLANK
SCANCOL:
	PUSH	D	;SAVE TABLE PTR
	PUSH	H	;SAVE PTR
SCOL1:
	MOV	A,M	;GET CHAR
	INX	H	;PT TO NEXT
	CPI	':'	;COLON?
	JZ	SCOLX
	CALL	DELCHK	;CHECK FOR DELIMITER
	JNZ	SCOL1
SCOL2:
	POP	H	;RESTORE
	POP	D
	RET
SCOLX:
	XCHG		;DE PTS TO AFTER COLON
	POP	H	;GET OLD PTR
	XCHG		;REPLACE IT
	POP	D	;GET TABLE PTR
	RET
;
; LOOK THROUGH DIRECTORY
;
FIND:
	XRA	A		;SELECT FIRST DISK
	STA	FCB
	CALL	NXTDISK		;GET INFO THE FIRST TIME
FIND1:
	RZ			;ABORT IF ERROR
FIND2:
	CALL	NXTSEC		;GET A DIRECTORY SECTOR
	JZ	FIND3		;RETURNS ZERO FLAG IF NO MORE
	CALL	CHKENT		;CHECK IT OUT
	JMP	FIND2		;KEEP IT UP TILL DONE
FIND3:
	CALL	DIRALPHA	;SORT ENTRIES
	CALL	PRFILES		;PRINT SORTED ENTRIES
	LDA	FCB		;NEXT DISK
	INR	A
	STA	FCB
	CALL	NXTDISK		;SELECT NEXT DISK
	JMP	FIND1

;
; SIGN OFF
;
BYE:
	MVI	C,13		;RESET SYSTEM
	CALL	BDOS
	LDA	FFLAG		;GET FILE FOUND FLAG
	ORA	A		;NO FILES FOUND?
	JNZ	RETURN
	CALL	PRINT
	DB	CR,LF,'NO Files Found',0
	JMP	RETURN
;
; CHECKS THE CURRENT 4 DIRECTORY ENTRIES AGAINST ARGUMENT
; IF MATCH, REWRITES SECTOR WITH REACTIVATED 1ST BYTES
;
CHKENT:
	MVI	B,4		;NUMBER OF ENTRIES PER SECTOR
	LXI 	H,TBUFF		;BEGINNING OF BUFFER
CKLUP:
	PUSH	B
	MOV	A,M
	CPI	0E5H		;CHECK FOR UNUSED
	JZ	CKINC
	XRA	A		;A=0
	STA	CLPFLG		;SET FLAG FOR NO ENTRIES FOUND
	LDA	FNCOUNT		;GET NUMBER OF FILE NAMES TO LOOK THRU
	MOV	B,A		;... IN B
	PUSH	H
	LHLD	FNTAB		;PT TO TABLE
	XCHG			;... IN DE
	POP	H
CKLUP1:
	PUSH	B		;SAVE COUNT
	PUSH 	H		;SAVE BEGINNING ADDRESS
	PUSH	D
	CALL	COMPAR		;COMPARE WITH ARGUMENT AND SAVE IF MATCH
	POP	D
	LXI	H,11		;PT TO NEXT ENTRY
	DAD	D
	XCHG
	POP	H
	POP	B
	DCR	B		;COUNT DOWN
	JNZ	CKLUP1
CKINC:
	POP	B
	LXI	D,32		;LENGTH OF ENTRY
	DAD	D
	DCR	B
	JNZ	CKLUP
	LHLD	DIRMAX
	DCX	H		;REDUCE SECTORS LEFT
	SHLD	DIRMAX
	LHLD	SECTOR		;POINT TO NEXT SECTOR
	INX	H
	SHLD	SECTOR
	XCHG
	LHLD	MAXSEC		;REACHED LIMIT?
	INX	H		;ONE MORE
	MOV	A,H		;CHECK HIGH
	CMP	D
	RNZ
	MOV	A,L		;CHECK LOW
	CMP	E
	RNZ
	LHLD	TRACK		;NEXT TRACK
	INX	H
	SHLD	TRACK
	LXI	H,1		;FIRST SECTOR OF NEXT TRACK
	SHLD	SECTOR
	RET
;
; COMPARE 11 BYTES OF DIRECTORY ENTRY AGAINST ARGUMENT; RNZ IF NOT MATCHED
;  DE PTS TO TABLE ENTRY TO COMPARE TO
;
COMPAR:
	LDA	CLPFLG		;GET FOUND FLAG
	ORA	A		;0=NO
	RNZ
	SHLD	TEMP		;Hold pointer in case of match
	INX	H
	XCHG
	MVI	B,11
CMPR1:
	LDAX	D		;GET DIRECTORY ENTRY CHARACTER
	ANI	7FH		;STRIP ANY FLAGS
	CMP	M
	JZ	CMPR2
	MOV	A,M
	CPI	'?'
	RNZ
CMPR2:
	INX	D
	INX	H		;BUMP TO NEXT CHARACTER
	DCR	B
	JNZ	CMPR1		;LOOP FOR 11 CHARACTERS
	PUSH	D		;SAVE ENTRY PTR
	LDAX	D		;GET EXTENT IN B
	MOV	B,A
	LDA	EXTENT		;GET EXTENT MASK
	CMP	B
	POP	D		;GET ENTRY PTR
	JC	CMPR4		;NO MATCH
	LDA	SYSTEM		;INCLUDE SYSTEM FILES?
	ORA	A		;0=NO
	JNZ	CMPR3
	DCX	D		;BACK UP 2 BYTES
	DCX	D
	LDAX	D		;GET T2
	ANI	80H		;CHECK FOR SYS
	RNZ
CMPR3:
	LHLD	TEMP		;CHECK FOR USER LIMIT
	MVI	A,31		;MAX USER
	CMP	M		;BEYOND MAX?
	JC	CMPR4
	LHLD	FCOUNT		;INCREMENT COUNT
	INX	H
	SHLD	FCOUNT
	LHLD	DSTART		;GET PTR TO NEXT ENTRY
	XCHG
	LHLD	TEMP
	MVI	B,ESIZE		;COPY ENTRY
	CALL	MOVE
	XCHG
	SHLD	DSTART		;PTR TO NEXT ENTRY
	XCHG
	LHLD	BDOS+1		;CHECK FOR MEMORY OVERFLOW
	MOV	A,H
	SUI	10		;BELOW CCP
	CMP	D		;PT BEYOND LIMIT?
	JC	MOVFL
	MVI	A,0FFH		;SET FOUND FLAG
	STA	FFLAG
	XRA	A
	RET			;RETURNS 'ZERO' FLAG SET FOR MATCH
CMPR4:
	MVI	A,0FFH		;NO MATCH
	ORA	A
	RET
MOVFL:
	CALL	PRINT
	DB	CR,LF,'ABORT -- Not Enough Memory for Buffers',0
	JMP	RETURN
;
;  ADVANCE TO NEXT DISK
;
NXTDISK:
	LXI	B,TBUFF		;SET DMA ADDRESS
	CALL	SETDMA
	LDA	FCB
	MOV	C,A
	MVI	B,0
	CALL	SELDSK		;MAKE SURE DRIVE IS
	MOV	A,H		;  SELECTED
	ORA	L
	RZ			;ERROR RETURN
	SHLD	DPH		;SAVE THE ADDRESS
	LXI	D,10		;PT TO DPB
	DAD	D
	MOV	E,M		;GET DPB ADDRESS IN HL
	INX	H
	MOV	D,M
	XCHG
	MOV	E,M		;NUMBER OF SECTORS/TRACK
	INX	H		;AS 2-BYTE QUANTITY IN DE
	MOV	D,M
	INX	H
	XCHG
	SHLD	MAXSEC		;SET MAX SECTORS/TRACK
	XCHG
	INX	H
	INX	H
	MOV	A,M		;GET EXM
	STA	EXTENT
	INX	H		;PT TO DRM
	INX	H
	INX	H
	MOV	E,M		;GET NUMBER OF
	INX	H		;  DIRECTORY ENTRIES
	MOV	D,M
	XCHG
	INX	H		;ACCOUNT FOR - 1
	SHLD	DSTART		;SAVE NUMBER OF DIRECTORY ENTRIES
	CALL	SHFHL2		;SHIFT 'HL' RIGHT 2
	SHLD	DIRMAX		;SAVE NUMBER DIRECTORY SECTORS
	LXI	H,5		;NOW POINT TO SYSTEM
	DAD	D		;  TRACK OFFSET
	MOV	A,M		;PICK UP NUMBER OF
	INX	H
	MOV	H,M
	MOV	L,A
	SHLD	TRACK
	LXI	H,1		;SET SECTOR
	SHLD	SECTOR
	LDA	ECOUNT		;LAST NEW LINE?
	ANI	3
	CNZ	CRLF
	CALL	PRINT
	DB	'Disk ',0
	LDA	FCB
	ADI	'A'
	CALL	COUT
	CALL	PRINT
	DB	' --',CR,LF,0
	LHLD	SCRATCH		;PT TO SCRATCH AREA
	SHLD	ORDER		;ADDRESS OF ORDER TABLE
	XCHG
	LHLD	DSTART		;GET NUMBER OF DIRECTORY ENTRIES
	DAD	H		;DOUBLE FOR NUMBER OF BYTES IN ORDER TABLE
	DAD	D		;PT TO FIRST BYTE OF DIRBUF
	SHLD	DIRBUF		;SET PTR
	SHLD	DSTART		;SET LOOP PTR
	LXI	H,0		;SET FILE COUNT
	SHLD	FCOUNT
	XRA	A		;SET COUNT
	STA	ECOUNT
	CMA			;FLIP
	ORA	A		;OK TO CONTINUE
	RET
;
; GET BIOS JUMPS VECTORS FOR EASY REFERENCE
;
GTBIOS:
	LHLD	BOOT+1		;POINTS TO BIOS JUMP TABLE+3
	LXI	D,WBOOT		;WHERE WE WILL KEEP A COPY
	MVI	B,16*3		;MOVE 48 BYTES AND FALL THRU TO MOVE
;
; GENERAL PURPOSE MOVE ROUTINE
; FROM 'HL' TO 'DE' FOR COUNT OF 8
;
MOVE:
	MOV	A,M		;GET A BYTE
	STAX	D		;PUT A BYTE
	INX	D		;INCREMENT TO NEXT
	INX	H
	DCR	B		;COUNT DOWN
	JNZ	MOVE
	RET
;
; READS NEXT SECTOR (GROUP OF FOUR DIRECTORY ENTRIES)
; RETURNS WITH ZERO FLAG SET IF NO MORE
;
NXTSEC:
	LHLD	DIRMAX		;SEE IF MORE SECTORS
	MOV	A,H
	ORA	L
	RZ			;RETURNS ZERO FLAG IF NO MORE
	LHLD	TRACK		;SET TRACK
	MOV	B,H
	MOV	C,L
	CALL	SETTRK
	LHLD	SECTOR		;SET SECTOR
	MOV	B,H
	MOV	C,L
	CALL	TRNSLT
	CALL	SETSEC
	CALL	READ		;READ A SECTOR
	ANI	1		;REVERSE SENSE OF ERROR FLAG
	XRI	1		;RETURNS WITH ZERO FLAG SET
	RET			;IF BAD READ
;
; PRINT FILES IN DIRBUF
;
PRFILES:
	LHLD	FCOUNT		;GET COUNT
	MOV	A,H		;ANY?
	ORA	L
	RZ
	MOV	B,H		;COUNT IN BC
	MOV	C,L
	LHLD	DIRBUF		;PT TO FIRST ONE
PRFLOOP:
	PUSH	B		;SAVE COUNT
	PUSH	H		;SAVE PTR
	CALL	PRINTFCB	;PRINT FCB
	POP	H		;GET REGS BACK
	POP	B
	LXI	D,ESIZE		;PT TO NEXT
	DAD	D
	DCX	B		;COUNT DOWN
	MOV	A,B
	ORA	C
	JNZ	PRFLOOP
	MVI	A,0FFH		;SET OK
	ORA	A
	RET
;
; FCB PRINTING ROUTINE
;
PRINTFCB:
	CALL	PRINT		;2 SPACES
	DB	'  ',0
	MOV	A,M		;GET USER NUMBER
	CALL	PADC		;PRINT IT
	MVI	A,':'
	CALL	COUT
	INX	H
PR0:
	MVI	B,8
	CALL	PR1
	MVI	A,'.'
	CALL	COUT
	MVI	B,3
	CALL	PR1
	LDA	ECOUNT		;INCREMENT COUNT
	INR	A
	STA	ECOUNT
	ANI	3		;EVERY 4
	CZ	CRLF		;NEW LINE
	RET
PR1:
	MOV	A,M
	ANI	7FH
	CALL	COUT
	INX	H
	DCR	B
	JNZ	PR1	
	RET
;
; SHIFT REGS 'HL' RIGHT 2 BITS LOGICAL
;
SHFHL2:
	CALL	SHFHL		;ROTATE RIGHT 1 BIT AND FALL THRU
SHFHL:
	XRA	A		;CLEAR CARRY
	MOV	A,H
	RAR			;SHIFTED BIT IN CARRY
	MOV	H,A
	MOV	A,L
	RAR
	MOV	L,A
	RET
;
; TRANSLATE REG 'BC' FROM LOGICAL TO PHYSICAL SECTOR NUMBER
;
TRNSLT:
	LHLD	DPH		;GET PTR TO DPH
	MOV	E,M		;GET ADDRESS OF XLT
	INX	H
	MOV	D,M
	CALL	SECTRAN		;USE BIOS ROUTINE
	MOV	C,L		;RETURN VALUE IN BC
	MOV	B,H
	RET

;
;  DIRALPHA -- ALPHABETIZES DIRECTORY PTED TO BY HL; BC CONTAINS
;	THE NUMBER OF FILES IN THE DIRECTORY
;
DIRALPHA:
	LHLD	FCOUNT	; GET FILE COUNT
	MOV	A,H	; ANY FILES?
	ORA	L
	RZ
	SHLD	N	; SET "N"
	MOV	B,H	; BC=COUNT
	MOV	C,L
	LHLD	DIRBUF	; PT TO DIRECTORY
;
;  SHELL SORT --
;    THIS SORT ROUTINE IS ADAPTED FROM "SOFTWARE TOOLS"
;    BY KERNIGAN AND PLAUGHER, PAGE 106.  COPYRIGHT, 1976, ADDISON-WESLEY.
;  ON ENTRY, BC=NUMBER OF ENTRIES AND HL=ADDRESS OF FIRST ENTRY
;
SORT:
	XCHG		; POINTER TO DIRECTORY IN DE
	LHLD	ORDER	; PT TO ORDER TABLE
;
;  SET UP ORDER TABLE; HL PTS TO NEXT ENTRY IN ORDER TABLE, DE PTS TO NEXT
;    ENTRY IN DIRECTORY, BC = NUMBER OF ELEMENTS REMAINING
;
SORT1:
	MOV	M,E	; STORE LOW-ORDER ADDRESS
	INX	H	; PT TO NEXT ORDER BYTE
	MOV	M,D	; STORE HIGH-ORDER ADDRESS
	INX	H	; PT TO NEXT ORDER ENTRY
	PUSH	H	; SAVE PTR
	LXI	H,ESIZE	; HL=NUMBER OF BYTES/ENTRY
	DAD	D	; PT TO NEXT DIR1 ENTRY
	XCHG		; DE PTS TO NEXT ENTRY
	POP	H	; GET PTR TO ORDER TABLE
	DCX	B	; COUNT DOWN
	MOV	A,B	; DONE?
	ORA	C
	JNZ	SORT1
;
;  THIS IS THE MAIN SORT LOOP FOR THE SHELL SORT IN "SOFTWARE TOOLS" BY K&P
;

;
;  SHELL SORT FROM "SOFTWARE TOOLS" BY KERNINGHAN AND PLAUGER
;
	LHLD	N	; NUMBER OF ITEMS TO SORT
	SHLD	GAP	; SET INITIAL GAP TO N FOR FIRST DIVISION BY 2

;  FOR (GAP = N/2; GAP > 0; GAP = GAP/2)
SRTL0:
	ORA	A	; CLEAR CARRY
	LHLD	GAP	; GET PREVIOUS GAP
	MOV	A,H	; ROTATE RIGHT TO DIVIDE BY 2
	RAR
	MOV	H,A
	MOV	A,L
	RAR
	MOV	L,A

;  TEST FOR ZERO
	ORA	H
	JZ	SDONE	; DONE WITH SORT IF GAP = 0

	SHLD	GAP	; SET VALUE OF GAP
	SHLD	I	; SET I=GAP FOR FOLLOWING LOOP

;  FOR (I = GAP + 1; I <= N; I = I + 1)
SRTL1:
	LHLD	I	; ADD 1 TO I
	INX	H
	SHLD	I

;  TEST FOR I <= N
	XCHG		; I IS IN DE
	LHLD	N	; GET N
	MOV	A,L	; COMPARE BY SUBTRACTION
	SUB	E
	MOV	A,H
	SBB	D	; CARRY SET MEANS I > N
	JC	SRTL0	; DON'T DO FOR LOOP IF I > N

	LHLD	I	; SET J = I INITIALLY FOR FIRST SUBTRACTION OF GAP
	SHLD	J

;  FOR (J = I - GAP; J > 0; J = J - GAP)
SRTL2:
	LHLD	GAP	; GET GAP
	XCHG		; ... IN DE
	LHLD	J	; GET J
	MOV	A,L	; COMPUTE J - GAP
	SUB	E
	MOV	L,A
	MOV	A,H
	SBB	D
	MOV	H,A
	SHLD	J	; J = J - GAP
	JC	SRTL1	; IF CARRY FROM SUBTRACTIONS, J < 0 AND ABORT
	MOV	A,H	; J=0?
	ORA	L
	JZ	SRTL1	; IF ZERO, J=0 AND ABORT

;  SET JG = J + GAP
	XCHG		; J IN DE
	LHLD	GAP	; GET GAP
	DAD	D	; J + GAP
	SHLD	JG	; JG = J + GAP

;  IF (V(J) <= V(JG))
	CALL	ICOMPARE	; J IN DE, JG IN HL

;  ... THEN BREAK
	JC	SRTL1

;  ... ELSE EXCHANGE
	LHLD	J	; SWAP J, JG
	XCHG
	LHLD	JG
	CALL	ISWAP	; J IN DE, JG IN HL

;  END OF INNER-MOST FOR LOOP
	JMP	SRTL2

;
;  SORT IS DONE -- RESTRUCTURE DIR1 IN SORTED ORDER IN PLACE
;
SDONE:
	LHLD	N	; NUMBER OF ENTRIES
	MOV	B,H	; ... IN BC
	MOV	C,L
	LHLD	ORDER	; PTR TO ORDERED POINTER TABLE
	SHLD	PTPTR	; SET PTR PTR
	LHLD	DIRBUF	; PTR TO UNORDERED DIRECTORY
	SHLD	PTDIR	; SET PTR DIR BUFFER

;  FIND PTR TO NEXT DIR1 ENTRY
SRTDN:
	LHLD	PTPTR	; PT TO REMAINING POINTERS
	XCHG		; ... IN DE
	LHLD	PTDIR	; HL PTS TO NEXT DIR ENTRY
	PUSH	B	; SAVE COUNT OF REMAINING ENTRIES

;  FIND PTR TABLE ENTRY
SRTDN1:
	LDAX	D	; GET CURRENT POINTER TABLE ENTRY VALUE
	INX	D	; PT TO HIGH-ORDER POINTER BYTE
	CMP	L	; COMPARE AGAINST DIR1 ADDRESS LOW
	JNZ	SRTDN2	; NOT FOUND YET
	LDAX	D	; LOW-ORDER BYTES MATCH -- GET HIGH-ORDER POINTER BYTE
	CMP	H	; COMPARE AGAINST DIR1 ADDRESS HIGH
	JZ	SRTDN3	; MATCH FOUND
SRTDN2:
	INX	D	; PT TO NEXT PTR TABLE ENTRY
	DCX	B	; COUNT DOWN
	MOV	A,C	; END OF TABLE?
	ORA	B
	JNZ	SRTDN1	; CONTINUE IF NOT

;  FATAL ERROR -- INTERNAL ERROR; POINTER TABLE NOT CONSISTENT
FERR$PTR:
	CALL	PRINT
	DB	0DH,0AH,'DIRALPHA -- Pointer Error',0
	JMP	RETURN

;  FOUND THE POINTER TABLE ENTRY WHICH POINTS TO THE NEXT UNORDERED DIR1 ENTRY
;    MAKE BOTH POINTERS (PTR TO NEXT, PTR TO CURRENT UNORDERED DIR1 ENTRY)
;    POINT TO SAME LOCATION (PTR TO NEXT DIR1 ENTRY TO BE ORDERED)
SRTDN3:
	LHLD	PTPTR	; GET PTR TO NEXT ORDERED ENTRY
	DCX	D	; DE PTS TO LOW-ORDER POINTER ADDRESS
	MOV	A,M	; MAKE PTR TO NEXT UNORDERED DIR1 PT TO BUFFER FOR
	STAX	D	;   DIR1 ENTRY TO BE MOVED TO NEXT UNORDERED DIR1 POS
	INX	H	; PT TO NEXT PTR ADDRESS
	INX	D
	MOV	A,M	; MAKE HIGH POINT SIMILARLY
	STAX	D

;  COPY NEXT UNORDERED DIR1 ENTRY TO HOLD BUFFER
	MVI	B,ESIZE	; B=NUMBER OF BYTES/ENTRY
	LHLD	PTDIR	; PT TO ENTRY
	LXI	D,HOLD	; PT TO HOLD BUFFER
	PUSH	B	; SAVE B=NUMBER OF BYTES/ENTRY
	CALL	MOVE
	POP	B

;  COPY TO-BE-ORDERED DIR1 ENTRY TO NEXT ORDERED DIR1 POSITION
	LHLD	PTPTR	; POINT TO ITS POINTER
	MOV	E,M	; GET LOW-ADDRESS POINTER
	INX	H
	MOV	D,M	; GET HIGH-ADDRESS POINTER
	LHLD	PTDIR	; DESTINATION ADDRESS FOR NEXT ORDERED DIR1 ENTRY
	XCHG		; HL PTS TO ENTRY TO BE MOVED, DE PTS TO DEST
	PUSH	B	; SAVE B=NUMBER OF BYTES/ENTRY
	CALL	MOVE
	POP	B
	XCHG		; HL PTS TO NEXT UNORDERED DIR1 ENTRY
	SHLD	PTDIR	; SET POINTER FOR NEXT LOOP

;  COPY ENTRY IN HOLD BUFFER TO LOC PREVIOUSLY HELD BY LATEST ORDERED ENTRY
	LHLD	PTPTR	; GET PTR TO PTR TO THE DESTINATION
	MOV	E,M	; GET LOW-ADDRESS POINTER
	INX	H
	MOV	D,M	; HIGH-ADDRESS POINTER
	LXI	H,HOLD	; HL PTS TO HOLD BUFFER, DE PTS TO ENTRY DEST
	CALL	MOVE	; B=NUMBER OF BYTES/ENTRY

;  POINT TO NEXT ENTRY IN POINTER TABLE
	LHLD	PTPTR	; POINTER TO CURRENT ENTRY
	INX	H	; SKIP OVER IT
	INX	H
	SHLD	PTPTR

;  COUNT DOWN
	POP	B	; GET COUNTER
	DCX	B	; COUNT DOWN
	MOV	A,C	; DONE?
	ORA	B
	JNZ	SRTDN
	RET		; DONE

;
;  SWAP (Exchange) the pointers in the ORDER table whose indexes are in
;    HL and DE
;
ISWAP:
	PUSH	H		; SAVE HL
	LHLD	ORDER		; ADDRESS OF ORDER TABLE - 2
	MOV	B,H		; ... IN BC
	MOV	C,L
	POP	H
	DCX	H		; ADJUST INDEX TO 0...N-1 FROM 1...N
	DAD	H		; HL PTS TO OFFSET ADDRESS INDICATED BY INDEX
				;   OF ORIGINAL HL (1, 2, ...)
	DAD	B		; HL NOW PTS TO POINTER INVOLVED
	XCHG			; DE NOW PTS TO POINTER INDEXED BY HL
	DCX	H		; ADJUST INDEX TO 0...N-1 FROM 1...N
	DAD	H		; HL PTS TO OFFSET ADDRESS INDICATED BY INDEX
				;   OF ORIGINAL DE (1, 2, ...)
	DAD	B		; HL NOW PTS TO POINTER INVOLVED
	MOV	C,M		; EXCHANGE POINTERS -- GET OLD (DE)
	LDAX	D		; -- GET OLD (HL)
	XCHG			; SWITCH
	MOV	M,C		; PUT NEW (HL)
	STAX	D		; PUT NEW (DE)
	INX	H		; PT TO NEXT BYTE OF POINTER
	INX	D
	MOV	C,M		; GET OLD (HL)
	LDAX	D		; GET OLD (DE)
	XCHG			; SWITCH
	MOV	M,C		; PUT NEW (DE)
	STAX	D		; PUT NEW (HL)
	RET
;
;  ICOMPARE compares the entry pointed to by the pointer pointed to by HL
;    with that pointed to by DE (1st level indirect addressing); on entry,
;    HL and DE contain the numbers of the elements to compare (1, 2, ...);
;    on exit, Carry Set means ((DE)) < ((HL)), Zero Set means ((HL)) = ((DE)),
;    and Non-Zero and No-Carry means ((DE)) > ((HL))
;
ICOMPARE:
	PUSH	H		; SAVE HL
	LHLD	ORDER		; ADDRESS OF ORDER - 2
	MOV	B,H		; ... IN BC
	MOV	C,L
	POP	H
	DCX	H		; ADJUST INDEX TO 0...N-1 FROM 1...N
	DAD	H		; DOUBLE THE ELEMENT NUMBER TO POINT TO THE PTR
	DAD	B		; ADD TO THIS THE BASE ADDRESS OF THE PTR TABLE
	XCHG			; RESULT IN DE
	DCX	H		; ADJUST INDEX TO 0...N-1 FROM 1...N
	DAD	H		; DO THE SAME WITH THE ORIGINAL DE
	DAD	B
	XCHG

;
;  HL NOW POINTS TO THE POINTER WHOSE INDEX WAS IN HL TO BEGIN WITH
;  DE NOW POINTS TO THE POINTER WHOSE INDEX WAS IN DE TO BEGIN WITH
;	FOR EXAMPLE, IF DE=5 AND HL=4, DE NOW POINTS TO THE 5TH PTR AND HL
; TO THE 4TH POINTER
;
	MOV	C,M		; BC IS MADE TO POINT TO THE OBJECT INDEXED TO
	INX	H		; ... BY THE ORIGINAL HL
	MOV	B,M
	XCHG
	MOV	E,M		; DE IS MADE TO POINT TO THE OBJECT INDEXED TO
	INX	H		; ... BY THE ORIGINAL DE
	MOV	D,M
	MOV	H,B		; SET HL = OBJECT PTED TO INDIRECTLY BY BC
	MOV	L,C

;
;  COMPARE DIR ENTRY PTED TO BY HL WITH THAT PTED TO BY DE;
;	NO NET EFFECT ON HL, DE; RET W/CARRY SET MEANS DE<HL
;	RET W/ZERO SET MEANS DE=HL
;
CMP$ENTRY:
;
;  COMPARE BY FILE NAME, FILE TYPE, EXTENSION, AND USER NUM (IN THAT ORDER)
;
	PUSH	H
	PUSH	D
	INX	H	; PT TO FN
	INX	D
	MVI	B,11	; COMPARE FN, FT
	CALL	COMP
	POP	D
	POP	H
	RNZ
	LDAX	D	; COMPARE USER NUMBER
	CMP	M
	RET
;
;  COMP COMPARES DE W/HL FOR B BYTES; RET W/CARRY IF DE<HL
;	MSB IS DISREGARDED
;
COMP:
	MOV	A,M	; GET (HL)
	ANI	7FH	; MASK MSB
	MOV	C,A	; ... IN C
	LDAX	D	; COMPARE
	ANI	7FH	; MASK MSB
	CMP	C
	RNZ
	INX	H	; PT TO NEXT
	INX	D
	DCR	B	; COUNT DOWN
	JNZ	COMP
	RET
;
;  AS COMP, BUT MATCH ON '?' PTED TO BY HL
;
COMP2:
	MOV	A,M	; GET (HL)
	ANI	7FH	; MASK MSB
	CPI	'?'	; MATCH '?'
	JZ	COMP2A
	MOV	C,A	; ... IN C
	LDAX	D	; COMPARE
	ANI	7FH	; MASK MSB
	CMP	C
	RNZ
COMP2A:
	INX	H	; PT TO NEXT
	INX	D
	DCR	B	; COUNT DOWN
	JNZ	COMP2
	RET

;
;  SORT BUFFERS
;
ORDER:
	DS	2	; PTR TO ORDER TABLE
DIRBUF:
	DS	2	; POINTER TO DIRECTORY
DSTART:
	DS	2	; POINTER TO FIRST DIRECTORY ENTRY
FCOUNT:
	DS	2	; TOTAL NUMBER OF FILES/NUMBER OF SELECTED FILES
HOLD:
	DS	ESIZE	; EXCHANGE HOLD BUFFER FOR FCB'S
PTPTR:
	DS	2	; POINTER POINTER
PTDIR:
	DS	2	; DIRECTORY POINTER
I:
	DS	2	; INDEXES FOR SORT
J:
	DS	2
JG:
	DS	2
N:
	DS	2	; NUMBER OF ELEMENTS TO SORT
GAP:
	DS	2	; BINARY GAP SIZE
;
; THIS IS THE WORKING COPY OF THE BIOS JUMP TABLE
;
WBOOT:	 DS	3
CONST:	 DS	3
CONIN:	 DS	3
CONOUT:	 DS	3
LIST:	 DS	3
PUNCH:	 DS	3
READER:	 DS	3
HOME:	 DS	3
SELDSK:	 DS	3
SETTRK:	 DS	3
SETSEC:	 DS	3
SETDMA:	 DS  	3
READ:	 DS	3
WRITE:	 DS	3
LISTST:	 DS	3
SECTRAN: DS	3
;
STACK:
	DS	2		;LOCATION OF STACK
;
; DATA AREAS
;
FNCOUNT:
	DS	1		;NUMBER OF FILE NAMES FOUND
CLPFLG:	DS	1		;0 FOR NO MATCH LOCALLY
SYSTEM:	DS	1		;0 IF NO SYSTEM FILES
ECOUNT:	DS	1		;COUNT OF ENTRIES PRINTED - 1
FFLAG:	DS	1		;FILE FOUND FLAG (0=NO)
TEMP:	DS	2		;TEMP STORAGE FOR FCB PRINT
;
;  DISK PARAMETER DATA
;
DPH:	DS	2		;ADDRESS OF DPH
DIRMAX:	DS	2		;NUMBER OF SECTORS IN DIRECTORY =
;				;   MAXIMUM NUMBER OF DIRECTORY ENTRIES
;				;   DIVIDED BY 4 (ENTRIES PER SECTOR)
EXTENT:	DS	1		;EXTENT MASK
MAXSEC:	DS	2		;MAXIMUM NUMBER OF SECTORS/TRACK
SECTOR:	DS	2		;CURRENT SECTOR NUMBER
TRACK:	DS	2		;TRACK NUMBER OF DIRECTORY

FNTAB:	DS	2		;FILE NAME TABLE

SCRATCH:
	DS	2		;SCRATCH AREA

	END