mirror of
https://github.com/microsoft/MS-DOS.git
synced 2024-11-25 07:05:45 +00:00
420 lines
17 KiB
NASM
420 lines
17 KiB
NASM
TITLE SORT FILTER FOR MS-DOS
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;
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; Sort /R /+n
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; /R -> reverse sort
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; /+n -> sort on column n
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;
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; Written by: Chris Peters
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;
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; Modification History:
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; 3-18-83 MZ Fix CR-LF at end of buffer
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; Fix small file sorting
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; Fix CR-LF line termination bug
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; Comment the Damn source
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;
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FALSE EQU 0
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TRUE EQU NOT FALSE
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;NOTE: "internat" must be false if KANJI version
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internat equ true
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;NOTE: see above
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.xlist
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.xcref
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INCLUDE DOSSYM.ASM
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.cref
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.list
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sys MACRO name ; system call macro
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MOV AH,name
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INT 21h
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ENDM
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save MACRO reglist ; push those registers
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IRP reg,<reglist>
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PUSH reg
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ENDM
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ENDM
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restore MACRO reglist ; pop those registers
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IRP reg,<reglist>
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POP reg
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ENDM
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ENDM
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MAXREC EQU 256 ; MAXIMUM NUL RECORD SIZE
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SPACE EQU 0 ; Offset zero in the allocated block
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BUFFER EQU MAXREC ; Offset MAXREC in the allocated block
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SUBTTL Segments used in load order
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CODE SEGMENT
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CODE ENDS
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CONST SEGMENT PUBLIC BYTE
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CONST ENDS
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CSTACK SEGMENT STACK
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DB 128 DUP (0) ; initial stack to be clear
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CSTACK ENDS
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DG GROUP CODE,CONST,CSTACK
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CODE SEGMENT
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ASSUME CS:DG,DS:NOTHING,ES:NOTHING,SS:CSTACK
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COLUMN DW 0 ; COLUMN TO USE FOR KEY + 1
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SWITCH DB '/'
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SORT:
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;
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; check for proper version number of system
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;
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sys GET_VERSION
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XCHG AH,AL ; Turn it around to AH.AL
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CMP AX,200H ; Version 2.00 only
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JAE OKDOS ; Success
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MOV DX,OFFSET DG:BADVER ; Get error message
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PUSH CS ; Get DS addressability
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POP DS
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sys STD_CON_STRING_OUTPUT ; Send to STDOUT
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PUSH ES ; long segment
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PUSH COLUMN ; offset zero
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LONG_RET PROC FAR
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RET ; long return to OS
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LONG_RET ENDP
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;
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; get proper switch character
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;
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OKDOS:
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MOV AL,0 ; Get current switch character
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sys CHAR_OPER
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MOV SWITCH,DL
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;
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; parse command line
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;
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MOV SI,80H ; pointer to command line
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CLD ; go left to right
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XOR CX,CX
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LODSB
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MOV CL,AL ; CX = length of command line
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SWITCH_LOOP:
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CALL GET_CHAR ; get a character
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CMP AL,SWITCH ; beginning of switch?
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JNZ SWITCH_LOOP ; No, get next character
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CALL GET_CHAR ; get 1st char of switch
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CMP AL,'+' ; Column to sort?
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JZ SWITCH_NUMBER ; Yes, parse a number
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OR AL,20h ; convert to lower case
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CMP AL,'r' ; Reverse sort?
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JNZ SWITCH_LOOP ; No, get next switch
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MOV CS:CODE_PATCH,72h ; sleaze JAE into JB
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JMP SWITCH_LOOP ; get next switch
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SWITCH_NUMBER:
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MOV COLUMN,0 ; start off at 0
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SWITCH_NEXT_NUMBER:
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CALL GET_CHAR ; get supposed digit
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SUB AL,'0' ; convert to number
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JB SWITCH_LOOP ; less than '0'
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CMP AL,9 ; is it a valid digit?
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JA SWITCH_LOOP ; nope, get next switch
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CBW ; make it a full word
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MOV BX,AX ; save byte away
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MOV AX,10 ; decimal number system
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MUL COLUMN ; take previous result
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ADD AX,BX ; add in low order digit
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MOV COLUMN,AX ; save away value
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JMP SWITCH_NEXT_NUMBER ; get next character
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GET_CHAR:
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JCXZ END_GET ; End of line
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DEC CX ; dec char count
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LODSB ; get the character
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RET ; return
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END_GET:
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POP AX ; nuke return on stack
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;
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; set up column for proper sort offset
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;
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END_SWITCH:
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ADD COLUMN,2
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CMP COLUMN,2
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JZ GOT_COL
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DEC COLUMN
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;
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; Get sorting area, no more than 64K
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;
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GOT_COL:
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MOV BX,1000H ; 64K worth of paragraphs
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GET_MEM:
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sys ALLOC ; allocate them from somewhere
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JNC GOT_MEM ; if error, BX has amount free, try to get it
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OR BX,BX ; but, is BX = 0?
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JNZ GET_MEM ; nope, try to allocate it
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JMP SIZERR ; complain
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GOT_MEM:
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MOV DS,AX ; Point DS to buffer
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MOV ES,AX ; and point ES to buffer
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MOV CL,4 ; 2^4 bytes per paragraph
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SHL BX,CL ; Find out how many bytes we have
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;
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; clear out temporary record area
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;
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MOV CX,MAXREC/2 ; Size of temporary buffer (words)
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MOV AX,' ' ; Character to fill with
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MOV DI,SPACE ; Beginning of temp buffer
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REP STOSW ; Blam.
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;
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; read in file from standard input
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;
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MOV DX,BUFFER + 2 ; DX = place to begin reading
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MOV CX,BX ; CX is the max number to read
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SUB CX,MAXREC + 2 ; remember offset of temp buffer
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SORTL:
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XOR BX,BX ; Standard input
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sys READ ; Read it in
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ADD DX,AX ; Bump pointer by count read
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SUB CX,AX ; subtract from remaining the count read
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JZ SIZERR ; if buffer is full then error
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OR AX,AX ; no chars read -> end of file
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JNZ SORTL ; there were chars read. go read again
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JMP SHORT SIZOK ; trim last ^Z terminated record
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SIZERR:
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MOV SI,OFFSET DG:ERRMSG ; not enough memory error
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ERROR_EXIT:
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PUSH CS ; DS addressability
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POP DS
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LODSW ; get length
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MOV CX,AX ; put into appropriate register
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MOV DX,SI ; get output destination
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MOV BX,2 ; output to standard error
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sys WRITE ; and write it out
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MOV AL,1 ; return an error code
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sys EXIT
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;
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; Look for a ^Z. Terminate buffer at 1st ^Z.
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;
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SIZOK:
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MOV BX,DX ; save end pointer
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MOV CX,DX ; get pointer to end of text
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SUB CX,BUFFER+2 ; dif in pointers is count
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MOV AL,1AH ; char is ^Z
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MOV DI,BUFFER+2 ; point to beginning of text
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REPNZ SCASB ; find one
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JNZ NoBack ; nope, try to find CRLF
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DEC BX ; pretend that we didn't see ^Z
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NoBack:
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SUB BX,CX ; sub from endpointer the number left
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SUB BX,2 ; Hope for a CR LF at end
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CMP WORD PTR [BX],0A0Dh ; Was there one there?
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JZ GOTEND ; yep, here is the end
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ADD BX,2 ; nope, bump back to SCASB spot
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CMP BYTE PTR [BX],AL ; Was there ^Z there?
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JZ GOTEND ; yep, chop it
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INC BX ; Nope, skip last char
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GOTEND:
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MOV BP,BX ; BP = filesize-2(CRLF)+temp buffer+2
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MOV WORD PTR DS:[BP],0 ; 0 at end of the file
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;
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; We now turn the entire buffer into a linked list of chains by
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; replacing CRLFs with the length of the following line (with 2 for CRLF)
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;
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MOV BX,BUFFER ; pointer to line head (length)
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MOV DI,BUFFER+2 ; pointer to line text
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REPLACE_LOOP:
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MOV AL,13 ; char to look for is CR
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MOV CX,BP ; count = end pointer
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SUB CX,DI ; chop off start point to get length
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INC CX ; add 1???
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REPLACE_SCAN:
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REPNZ SCASB ; look for CR
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JNZ REPLACE_SKIP ; count exhausted
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CMP BYTE PTR [DI],10 ; LF there?
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JNZ REPLACE_SCAN ; nope, continue scanning
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REPLACE_SKIP:
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MOV AX,DI ; AX to point after CR
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DEC AX ; AX to point to CR
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save <AX> ; save pointer
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SUB AX,BX ; AX is length of line found
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MOV [BX],AX ; stuff it in previous link
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restore <BX> ; get pointer to next
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INC DI ; skip LF???
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JCXZ END_REPLACE_LOOP ; no more to scan -> go sort
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JMP REPLACE_LOOP ; look for next
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END_REPLACE_LOOP:
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MOV WORD PTR [BX],0 ; terminate file with nul
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LEA BP,[BX+2] ; remember the null line at end
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MOV DI,BUFFER ; DI is start of unsorted section
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;
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; begin sort. Outer loop steps over all unsorted lines
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;
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OUTER_SORT_LOOP:
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MOV BX,DI ; BX is start of unsorted section
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MOV SI,BX ; SI is scanning place link
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CMP WORD PTR [BX],0 ; are we at the end of the buffer?
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JNZ INNER_SORT_LOOP ; No, do inner process
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JMP END_OUTER_SORT_LOOP ; yes, go dump out
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;
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; BX points to best guy found so far. We scan through the sorted section
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; to find an appropriate insertion point
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;
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INNER_SORT_LOOP:
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ADD SI,[SI] ; link to next fellow
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MOV AX,[SI] ; get length of comparison guy
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OR AX,AX ; test for end of buffer
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JZ END_INNER_SORT_LOOP ; if zero then figure out insertion
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save <SI,DI> ; save SI,DI
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MOV DI,BX ; DI = pointer to tester link
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SUB AX,COLUMN ; adjust length for column
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JA AXOK ; more chars in tester than column?
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MOV SI,SPACE ; point SI to blank area
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MOV AX,MAXREC ; make AX be max length
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AXOK:
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MOV DX,[DI] ; get length of best guy
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SUB DX,COLUMN ; adjust length for column
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JA DXOK ; there are more chars after column
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MOV DI,SPACE ; point air to a space
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MOV DX,MAXREC ; really big record
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DXOK:
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MOV CX,AX ; AX is shortest record
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CMP AX,DX ; perhaps DX is shorter
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JB SMALL ; nope, leace CX alone
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MOV CX,DX ; DX is shorter, put length in CX
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SMALL:
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ADD DI,COLUMN ; offset into record
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ADD SI,COLUMN ; offset into other record
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if not internat
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REPZ CMPSB ; compare every one
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endif
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if internat
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push bx
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push ax
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mov bx,offset dg:table
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tloop: lodsb
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xlat byte ptr cs:[bx]
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mov ah,al
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mov al,es:[di]
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inc di
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xlat byte ptr cs:[bx]
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cmp ah,al
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loopz tloop
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pop ax
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pop bx
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endif
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restore <DI,SI> ; get head pointers back
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JNZ TESTED_NOT_EQUAL ; didn't exhaust counter, conditions set
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CMP AX,DX ; check string lengths
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TESTED_NOT_EQUAL:
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;
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; note! jae is patched to a jbe if file is to be sorted in reverse!
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;
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CODE_PATCH LABEL BYTE
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JAE INNER_SORT_LOOP ; if this one wasn't better then go again
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MOV BX,SI ; it was better, save header
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JMP INNER_SORT_LOOP ; and scan again
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END_INNER_SORT_LOOP:
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MOV SI,BX ; SI is now the best person
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CMP SI,DI ; check best for current
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JZ END_INSERT ; best equals current, all done
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;
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; SI points to best line found so far
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; DI points to a place to insert this line
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; DI is guaranteed to be < SI
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; make room for line at destination
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;
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MOV DX,[SI] ; get length of line
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save <SI,DI> ; save positions of people
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STD ; go right to left
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MOV CX,BP ; get end of file pointer
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SUB CX,DI ; get length from destination to end
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MOV SI,BP ; start from end
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DEC SI ; SI points to end of file
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MOV DI,SI ; destination is end of file
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ADD DI,DX ; DI points to new end of file
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REP MOVSB ; blam. Move every one up
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CLD ; back left to right
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restore <DI,SI> ; get old source and destination
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;
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; MOVE NEW LINE INTO PLACE
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;
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save <DI> ; save destination
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ADD SI,DX ; adjust for previous movement
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save <SI> ; save this value
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MOV CX,DX ; get number to move
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REP MOVSB ; blam. move the new line in
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restore <SI,DI> ; get back destination and new source
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;
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; DELETE LINE FROM OLD PLACE
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;
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save <DI> ; save destination
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MOV CX,BP ; pointer to end
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ADD CX,DX ; remember bump
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SUB CX,SI ; get count of bytes to move
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INC CX ; turn it into a word
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SHR CX,1 ; or a count of words
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MOV DI,SI ; new destination of move
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ADD SI,DX ; offset of block
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REP MOVSW ; blam, squeeze out the space
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restore <DI> ; get back original destination
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MOV WORD PTR DS:[BP-2],0 ; remake the end of file mark
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END_INSERT:
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ADD DI,[DI] ; link to next guy
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JMP OUTER_SORT_LOOP ; and continue
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;
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; PUT BACK IN THE CR-LF
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;
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END_OUTER_SORT_LOOP:
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MOV DI,BUFFER ; start at beginning (where else)
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MOV CX,[DI] ; count of butes
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INSERT_LOOP:
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ADD DI,CX ; point to next length
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MOV CX,[DI] ; get length
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MOV WORD PTR [DI],0A0DH ; replace length with CRLF
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CMP CX,0 ; check for end of file
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JNZ INSERT_LOOP ; nope, try again
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WRITE_FILE:
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MOV DX,BUFFER+2 ; get starting point
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MOV CX,BP ; pointer to end of buffer
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SUB CX,DX ; dif in pointers is number of bytes
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MOV BX,1 ; to standard output
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sys WRITE ; write 'em out
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JC BADWRT ; some bizarre error -> flag it
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CMP AX,CX ; did we write what was expected?
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JZ WRTOK ; yes, say bye bye
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BADWRT:
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MOV SI,OFFSET dg:ERRMSG2 ; strange write error
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JMP ERROR_EXIT ; bye bye
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WRTOK:
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XOR AL,AL ; perfect return (by convention)
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sys EXIT ; bye!
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CODE ENDS
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CONST SEGMENT PUBLIC BYTE
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EXTRN BADVER:BYTE,ERRMSG:BYTE,ERRMSG2:BYTE
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if internat
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extrn table:byte
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endif
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CONST ENDS
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SUBTTL Initialized Data
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PAGE
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CSTACK SEGMENT STACK
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DB 96 dup (0)
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CSTACK ENDS
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END SORT
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