514 lines
14 KiB
NASM
514 lines
14 KiB
NASM
title LOCATE (EXE2BIN)
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;Loader for EXE files under 86-DOS
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;The following switch allows use with the "old linker", which put a version
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;number where the new linker puts the number of bytes used in the last page.
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;If enabled, this will cause a test for 0004 at this location (the old linker
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;version number), and if equal, change it to 200H so all of the last page
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;will be used.
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;VER. 1.5
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; 05/21/82 Added rev number
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;
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;VER. 1.6
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; 07/01/82 A little less choosy about size matches
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;
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;VER. 2.0 Rev. 1 M.A.Ulloa
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; 10/08/82 Modified to use new 2.0 system calls for file i/o
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;
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; Rev. 2 M.A.Ulloa
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; 10/27/82 Added the DOS version check
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FALSE EQU 0
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TRUE EQU NOT FALSE
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OLDLINK EQU 0 ;1 to enable, 0 to disable
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.xlist
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INCLUDE DOSSYM.ASM
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.list
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subttl Main Code Area
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page
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code segment byte
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code ends
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DATA SEGMENT PUBLIC BYTE
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EXTRN bad_vers_err:BYTE,NOTFND:BYTE,NOROOM:BYTE,DIRFULL:BYTE
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EXTRN CANTFIX:BYTE,RDBAD:BYTE,FULL:BYTE,PROMPT:BYTE,CRLF:BYTE
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make db "MAUlloa/Microsoft/V20"
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rev db "2"
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file1_ext db ".EXE",00h
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file2_ext db ".BIN",00h
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per1 db 0
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per2 db 0
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file1 db 64 dup(?)
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handle1 dw 1 dup(?)
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file2 db 64 dup(?)
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handle2 dw 1 dup(?)
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INBUF DB 5,0
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DB 5 DUP(?)
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;The following locations must be defined for storing the header:
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RUNVAR LABEL BYTE ;Start of RUN variables
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RELPT DW ?
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LASTP LABEL WORD
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RELSEG DW ?
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SIZ LABEL WORD ;Share these locations
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PAGES DW ?
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RELCNT DW ?
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HEADSIZ DW ?
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DW ?
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LOADLOW DW ?
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INITSS DW ?
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INITSP DW ?
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DW ?
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INITIP DW ?
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INITCS DW ?
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RELTAB DW ?
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RUNVARSIZ EQU $-RUNVAR
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DATA ENDS
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STACK SEGMENT WORD STACK
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DB 80H DUP (?)
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STACK ENDS
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ZLOAD SEGMENT
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ZLOAD ENDS
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LOAD EQU ZLOAD
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CODE SEGMENT BYTE
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ASSUME CS:CODE
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LOCATE PROC FAR
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JMP SHORT LOCSTRT
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HEADER DB "Vers 2.00"
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LOCSTRT:
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MOV SI,81H
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PUSH DS
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XOR AX,AX
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PUSH AX ;Push return address to DS:0
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;Code to print header
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; PUSH DS
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; MOV DX,DATA
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; MOV DS,DX
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; MOV DX,OFFSET HEADER
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; MOV AH,STD_CON_STRING_OUTPUT
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; INT 21H
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; POP DS
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;----- Check Version Number --------------------------------------------;
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mov ah,Get_Version
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int 21h
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cmp al,2
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jge vers_ok ; version >= 2, enter locate
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push ds
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mov dx,data
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mov ds,dx
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mov dx,offset bad_vers_err
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MOV AH,STD_CON_STRING_OUTPUT
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INT 21H
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pop ds
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ret ;long return to DOS
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;-----------------------------------------------------------------------;
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vers_ok:
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MOV BX,WORD PTR DS:2 ;Get size of memory
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MOV DX,DATA
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MOV ES,DX
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assume es:data
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;-----------------------------------------------------------------------;
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;----- Get the first file name
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call kill_bl
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jnc sj01
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mov ds,dx
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jmp bad_file
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sj01:
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mov di,offset file1
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sj0:
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lodsb ;get character of file name
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cmp al,' '
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je sj2
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cmp al,0dh
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je sj2
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cmp al,'.' ;an extension separator found?
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jne sj1
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mov es:[per1],-1
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sj1:
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stosb
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jmp short sj0
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sj2:
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dec si
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mov byte ptr es:[di],00h ;nul terminate the filename
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call kill_bl
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jc no_second
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;----- Get the second file name
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mov di,offset file2
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sj3:
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lodsb ;get character of file name
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cmp al,' '
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je sj5
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cmp al,0dh
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je sj5
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cmp al,'.' ;an extension separator found?
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jne sj4
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mov es:[per2],-1
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sj4:
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stosb
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jmp short sj3
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sj5:
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mov byte ptr es:[di],00h ;nul terminate
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jmp short check_ext
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;----- Copy file1 to file2
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no_second:
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mov ds,dx
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assume ds:data
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mov si,offset file1
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mov di,offset file2
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sj6:
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lodsb
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cmp al,'.'
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je sj7
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cmp al,00h
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je sj7
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stosb
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jmp short sj6
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sj7:
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mov byte ptr [di],00h
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;----- Check that files have an extension, otherwise set default
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check_ext:
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mov ds,dx
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assume ds:data
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cmp [per1],-1
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je file1_ok
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mov si,offset file1
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sj8:
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lodsb
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cmp al,00h
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jne sj8
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mov di,si
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mov si,offset file1_ext
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call put_ext
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file1_ok:
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cmp [per2],-1
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je file2_ok
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mov si,offset file2
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sj9:
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lodsb
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cmp al,00h
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jne sj9
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mov di,si
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mov si,offset file2_ext
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call put_ext
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jmp short file2_ok
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;----- Fill in the default extent
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put_ext proc near
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dec di
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mov cx,5 ;move extent: period,extent,null
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rep movsb
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ret
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put_ext endp
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;----- Find the first non-blank
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kill_bl proc near
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cld
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sj10:
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lodsb
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cmp al,' '
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je sj10
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dec si
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cmp al,0dh
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clc
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jne sj11
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stc
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sj11:
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ret
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kill_bl endp
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file2_ok:
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;-----------------------------------------------------------------------;
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mov dx,offset file1
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mov ah,open
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mov al,0 ;ror reading only
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INT 21H ;Open input file
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jc bad_file
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mov [handle1],ax
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jmp exeload
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bad_file:
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MOV DX,OFFSET NOTFND
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xERROR:
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MOV AH,STD_CON_STRING_OUTPUT
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INT 21H
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RET ;FAR return to MS-DOS
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TOOBIG:
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MOV DX,OFFSET NOROOM
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JMP xERROR
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BADEXE:
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MOV DX,OFFSET CANTFIX
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ERRORJ: JMP xERROR
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EXELOAD:
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MOV DX,OFFSET RUNVAR ;Read header in here
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MOV CX,RUNVARSIZ ;Amount of header info we need
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push bx
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mov bx,[handle1]
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MOV AH,read
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INT 21H ;Read in header
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pop bx
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CMP [RELPT],5A4DH ;Check signature word
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JNZ BADEXE
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MOV AX,[HEADSIZ] ;size of header in paragraphs
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ADD AX,31 ;Round up first
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CMP AX,1000H ;Must not be >=64K
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JAE TOOBIG
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AND AX,NOT 31
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MOV CL,4
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SHL AX,CL ;Header size in bytes
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push dx
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push cx
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push ax
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push bx
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mov dx,ax
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xor cx,cx
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mov al,0
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mov bx,[handle1]
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mov ah,lseek
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int 21h
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pop bx
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pop ax
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pop cx
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pop dx
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XCHG AL,AH
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SHR AX,1 ;Convert to pages
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MOV DX,[PAGES] ;Total size of file in 512-byte pages
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SUB DX,AX ;Size of program in pages
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CMP DX,80H ;Fit in 64K?
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JAE TOOBIG
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XCHG DH,DL
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SHL DX,1 ;Convert pages to bytes
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MOV AX,[LASTP] ;Get count of bytes in last page
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OR AX,AX ;If zero, use all of last page
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JZ WHOLEP
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IF OLDLINK
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CMP AX,4 ;Produced by old linker?
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JZ WHOLEP ;If so, use all of last page too
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ENDIF
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SUB DX,200H ;Subtract last page
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ADD DX,AX ;Add in byte count for last page
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WHOLEP:
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MOV [SIZ],DX
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ADD DX,15
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SHR DX,CL ;Convert bytes to paragraphs
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MOV BP,LOAD
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ADD DX,BP ;Size + start = minimum memory (paragr.)
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CMP DX,BX ;Enough memory?
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JA TOOBIG
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MOV DX,OFFSET CANTFIX
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MOV AX,[INITSS]
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OR AX,[INITSP]
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OR AX,[INITCS]
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ERRORNZ:
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jz xj
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JMP ERRORJ ;Must not have SS, SP, or CS to init.
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xj: MOV AX,[INITIP]
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OR AX,AX ;If IP=0, do binary fix
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JZ BINFIX
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CMP AX,100H ;COM file must be set up for CS:100
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JNZ ERRORNZ
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push dx
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push cx
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push ax
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push bx
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mov dx,100h ;chop off first 100h
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xor cx,cx
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mov al,1 ;seek from current position
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mov bx,[handle1]
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mov ah,lseek
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int 21h
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pop bx
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pop ax
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pop cx
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pop dx
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SUB [SIZ],AX ;And count decreased size
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CMP [RELCNT],0 ;Must have no fixups
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JNZ ERRORNZ
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BINFIX:
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XOR BX,BX ;Initialize fixup segment
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;See if segment fixups needed
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CMP [RELCNT],0
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JZ LOADEXE
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GETSEG:
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MOV DX,OFFSET PROMPT
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MOV AH,STD_CON_STRING_OUTPUT
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INT 21H
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MOV AH,STD_CON_STRING_INPUT
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MOV DX,OFFSET INBUF
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INT 21H ;Get user response
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MOV DX,OFFSET CRLF
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MOV AH,STD_CON_STRING_OUTPUT
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INT 21H
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MOV SI,OFFSET INBUF+2
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MOV BYTE PTR [SI-1],0 ;Any digits?
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JZ GETSEG
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DIGLP:
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LODSB
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SUB AL,"0"
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JC DIGERR
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CMP AL,10
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JB HAVDIG
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AND AL,5FH ;Convert to upper case
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SUB AL,7
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CMP AL,10
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JB DIGERR
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CMP AL,10H
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JAE DIGERR
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HAVDIG:
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SHL BX,1
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SHL BX,1
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SHL BX,1
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SHL BX,1
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OR BL,AL
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JMP DIGLP
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DIGERR:
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CMP BYTE PTR [SI-1],0DH ;Is last char. a CR?
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JNZ GETSEG
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LOADEXE:
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XCHG BX,BP ;BX has LOAD, BP has fixup
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MOV CX,[SIZ]
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MOV AH,read
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push di
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mov di,[handle1]
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PUSH DS
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MOV DS,BX
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XOR DX,DX
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push bx
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mov bx,di
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INT 21H ;Read in up to 64K
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pop bx
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POP DS
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pop di
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Jnc HAVEXE ;Did we get it all?
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MOV DX,OFFSET RDBAD
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jmp xERROR ;Non fatal, print warning
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HAVEXE:
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CMP [RELCNT],0 ;Any fixups to do?
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JZ STORE
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MOV AX,[RELTAB] ;Get position of table
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push dx
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push cx
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push ax
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push bx
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mov dx,ax
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xor cx,cx
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mov al,0
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mov bx,[handle1]
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mov ah,lseek
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int 21h
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pop bx
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pop ax
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pop cx
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pop dx
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MOV DX,OFFSET RELPT ;4-byte buffer for relocation address
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RELOC:
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MOV DX,OFFSET RELPT ;4-byte buffer for relocation address
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MOV CX,4
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MOV AH,read
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push bx
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mov bx,[handle1]
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INT 21H ;Read in one relocation pointer
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pop bx
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Jnc RDCMP
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JMP BADEXE
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RDCMP:
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MOV DI,[RELPT] ;Get offset of relocation pointer
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MOV AX,[RELSEG] ;Get segment
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ADD AX,BX ;Bias segment with actual load segment
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MOV ES,AX
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ADD ES:[DI],BP ;Relocate
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DEC [RELCNT] ;Count off
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JNZ RELOC
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STORE:
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MOV AH,CREAT
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MOV DX,OFFSET file2
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xor cx,cx
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INT 21H
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Jc MKERR
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mov [handle2],ax
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MOV CX,[SIZ]
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MOV AH,write
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push di
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mov di,[handle2]
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PUSH DS
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MOV DS,BX
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XOR DX,DX ;Address 0 in segment
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push bx
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mov bx,di
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INT 21H
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pop bx
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POP DS
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pop di
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Jc WRTERR ;Must be zero if more to come
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MOV AH,CLOSE
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push bx
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mov bx,[handle2]
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INT 21H
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pop bx
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RET
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WRTERR:
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MOV DX,OFFSET FULL
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JMP xERROR
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MKERR:
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MOV DX,OFFSET DIRFULL
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JMP xERROR
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LOCATE ENDP
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CODE ENDS
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END LOCATE
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