page 60,132 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; Copyright (C) 1984 David Micon ; ; This code may be freely copied or modified, but not sold for ; profit. ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; title data path name dpath CR equ 0dh intseg segment at 0 org 21h*4 int21 label word intseg ends code segment para assume cs:code org 100h start: jmp loaddpath oldint21 dd ? ;old interrupt lstptr dw ? ;dir lst ptr defdrv db ? ;default drive func db ? ;interrupt function alsave db ? ;interrupt al loadflag db ? ;load interrupt flag even dpathid equ 4213h id dw 0 newint21 label far sti cmp ah,0fh ;open? je doint0f ;yes cmp ah,17h ;rename? je doint0f ;yes jmp oldint21 doint0f: mov func,ah ;save function mov alsave,al ;save al pushf call oldint21 ;do open cmp al,0 ;in current dir? jne notincurrent ;no iret notincurrent: mov lstptr,81h ;initialize lstptr mov ah,19h int 21h ;get default drive mov defdrv,al ;save default drive push dx push si push ds push cs pop ds mov si,0 mov byte ptr [si],'\' ;put in initial char inc si ;to next char xor dl,dl ;do default drive mov ah,47h int 21h ;get current directory pop ds pop si pop dx lstloop: push di push ds push cs pop ds ;ds=cs mov di,ds:lstptr cmp byte ptr [di],0 ;done? je lstdone ;yes push dx mov dl,defdrv ;get default drive mov ah,0eh int 21h ;set default drive cmp byte ptr [di+1],':' ;drive change needed? jne nochgdrv ;no mov dl,[di] ;get drive letter and dl,0dfh ;make upper case sub dl,'A' ;convert to binary mov ah,0eh int 21h ;change default drive nochgdrv: mov dx,di ;point to string mov ah,3bh int 21h ;change default directory pop dx pop ds pop di jc nxtlst ;br if dir does not exist mov ah,func ;set function mov al,alsave ;restore al pushf call oldint21 ;do function cmp al,0 ;function ok? je leave ;yes nxtlst: push cx push di push es push cs pop es ;es=cs mov di,lstptr ;get list ptr mov cx,80h ;set count mov al,0 repnz scasb ;look for null mov lstptr,di ;set new list ptr pop es pop di pop cx jmp lstloop lstdone: pop ds pop di mov ah,func ;put in func mov al,0ffh leave: push ax push dx push ds push cs pop ds ;ds=cs mov dl,defdrv mov ah,0eh int 21h ;restore default drive mov dx,0 mov ah,3bh int 21h ;set dir pop ds pop dx pop ax iret loaddpath: call srchdpath ;dpath installed? jnc loaded ;yes mov loadflag,1 ;set load flag push cs pop es jmp short procargs loaded: mov loadflag,0 ;reset load flag mov ax,es ;get search seg xor dx,dx ;clear high part mov cx,4 shftlp: shl ax,1 ;shift low rcl dx,1 ;shift high loop shftlp add ax,di ;add offset adc dx,0 ;add possible carry sub ax,(offset id-offset start)+102h ;sub offset sbb dx,0 ;sub possible borrow mov cx,4 shftlp1: shr dx,1 ;shift high rcr ax,1 ;shift low loop shftlp1 mov es,ax ;point to old segment procargs: push cs pop ds ;ds=cs mov si,81h ;point to src mov di,si ;point to dst cld ;move forward mov byte ptr es:[di-1],1 ;make byte before 1st arg non-zero firstlp: lodsb cmp al,' ' ;blank? je firstlp ;yes cmp al,CR ;CR? jne argloopst ;no cmp loadflag,0 ;loaded? je prtdpath ;yes mov dx,offset noloadmsg mov ah,9 int 21h ;print msg int 20h prtdpath: mov dx,offset dpathmsg mov ah,9 int 21h ;print dpath msg dec si ;move back push es pop ds ;ds=es mov si,81h ;point to beginning of path names prtloop: lodsb ;get byte cmp al,0 ;null? je prtpathend ;yes mov dl,al mov ah,2 int 21h ;print char jmp prtloop prtpathend: mov dl,';' mov ah,2 int 21h ;print semicolon cmp byte ptr [si],0 ;at end? jne prtloop ;no push cs pop ds ;ds=cs mov dx,offset crlfmsg mov ah,9 int 21h ;print CRLF int 20h argloopst: dec si ;move back argloop: lodsb ;get arg char cmp al,CR ;CR? je docr ;yes cmp al,' ' ;space? je argloop ;yes, skip cmp al,';' ;semicolon? jne notsemi ;yes mov al,0 ;set null notsemi: stosb ;put char in dst jmp argloop docr: mov al,0 cmp al,byte ptr es:[di-1] ;already null at end? je nullatend ;yes stosb ;put in null nullatend: stosb ;put in null cmp loadflag,0 ;load? jne doload ;yes int 20h doload: mov dx,offset loadmsg mov ah,9 int 21h mov id,dpathid mov ax,intseg mov ds,ax assume ds:intseg mov ax,int21+2 ;get int seg mov word ptr oldint21+2,ax ;save it mov ax,int21 ;get int offset mov word ptr oldint21,ax ;save it mov int21+2,cs ;set new int seg mov int21,offset newint21 ;set new int offset assume ds:nothing mov dx,offset loaddpath int 27h srchdpath proc near xor ax,ax ;start at segment 0 cld blkloop: mov es,ax ;set segment mov cx,4000h ;set count mov di,0 mov ax,dpathid loop1: repnz scasw ;look for 1st word jnz nxtblk ;no dpath found in this 32k block push cx ;save cnt push di ;save ptr mov si,offset id+2 ;set code offset mov cx,(offset loaddpath-offset id)-2 repz cmpsb ;see if rest is here pop di ;restore ptr pop cx ;restore cnt jnz loop1 ;search unsuccessful clc ;set found flag ret nxtblk: mov ax,es ;get es add ax,800h ;to next block mov dx,cs cmp ax,dx ;done? jb blkloop ;no stc ;set not found flag ret srchdpath endp loadmsg db 'Resident part of dpath loaded',13,10,'$' noloadmsg db 'Dpath not loaded' crlfmsg db 13,10,'$' dpathmsg db 'DPATH=$' code ends end start ied co