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name dev
page 60,132
title 'DEV --- Report installed device drivers'
; DEV --- a utility to report device header information for
; all installed device drivers
;
; Requires PC-DOS or MS-DOS 2.0.
;
; Used in the form:
; A>DEV
;
; version 1.0 December 12, 1984
; Copyright (c) 1984 by Ray Duncan
cr equ 0dh ;ASCII carriage return
lf equ 0ah ;ASCII line feed
blankequ20h;ASCII space code
eomequ'$';end of string marker
csegsegmentpara public 'CODE'
assumecs:cseg,ds:data,es:data,ss:stack
dev proc far ;entry point from PC-DOS
push ds ;save DS:0000 for final
xor ax,ax ;return to PC-DOS
push ax
mov ax,data ;make our data segment
movds,ax;addressable via DS and ES.
mov es,ax
mov ah,30h;check version of PC-DOS.
int 21h
cmp al,2
jae dev1;proceed, DOS 2.0 or greater.
mov dx,offset msg2 ;DOS 1.x --- print error message.
jmpdev6
dev1:movcx,ax;save DOS version number.
movah,15;now try and open the "NUL" device.
movdx,offset nulfcb
int21h
oral,al;opened successfully?
jzdev2;yes, jump.
movdx,offset msg1;no, print error msg and exit.
jmpdev6
dev2:;Pick up double pointer to device
;driver chain out of reserved
;area in fcb. This area is mapped
;differently in DOS 2.x and DOS 3.x.
cmpcl,2;is this DOS 2.x?
jadev3;no, jump.
movbx,word ptr nulfcb+25
moves,word ptr nulfcb+27
jmpdev4
dev3:;come here if DOS 3.0 or greater.
movbx,word ptr nulfcb+26
moves,word ptr nulfcb+28
dev4:callheader;print sign-on message and
;column headings.
dev5:;trace through the device chain
callprdev;print device header information
;for driver pointed to by ES:BX.
;pick up addr of next header.
lesbx,dword ptr es:[bx]
cmpbx,-1;found last one yet?
jnedev5;no, try next.
movdx,offset msg3;yes, print "end of device chain".
dev6: movah,9;print the string whose address
int21h;is in DX.
ret;then return to DOS.
dev endp
headerprocnear;print out headings for device
movdx,offset hdr;driver information.
movah,9
int21h
ret
headerendp
prdevprocnear;print out device driver info.
;ES:BX is pointer to device header,
;which must be preserved.
movax,es;convert segment of device header
movdi,offset inf1
callhexasc
movax,bx;convert offset of device header.
movdi,offset inf2
callhexasc
movax,es:[bx+4];get attribute word, save a
pushax;copy of it, then convert it.
movdi,offset inf3
callhexasc
movax,es:[bx+6];convert ptr to device strategy.
movdi,offset inf4
callhexasc
movax,es:[bx+8];convert ptr to device int handler.
movdi,offset inf5
callhexasc
;if not char device, clear out name
;field and set number of units.
popax;get back attribute word.
testax,08000h;is bit 15 = 1 ?
jnzprdev7;yes, it's character dev, jump.
;no, it's block device.
;set flag to skip device name.
mov byte ptr inf8,eom
moval,es:[bx+10];pick up number of units.
aam;convert to ASCII decimal and
addax,'00';store into output string.
movbyte ptr inf7+1,al
movbyte ptr inf7,ah
;set type = B for Block
movbyte ptr inf6,'B'
jmpprdev9
prdev7:;if char device, move its 8-character
;name into the output string.
xorsi,si
prdev8:moval,es:[si+bx+10]
mov[si+inf8],al
incsi
cmpsi,8
jneprdev8
;remove # of units field.
movword ptr inf7,' '
;set type = C for Character.
movbyte ptr inf6,'C'
prdev9: movdx,offset inf;now print device information
movah,9;and exit.
int21h
ret
prdevendp
hexascprocnear;convert binary word to hex ASCII.
;call with AX=binary value
; DI=addr to store string
;returns AX, CX, DI destroyed.
pushax;save copy of original value.
moval,ah
callbtoa;convert upper byte.
adddi,2;increment output address.
popax
callbtoa;convert lower byte.
ret;return to caller.
hexascendp
btoaprocnear;convert binary byte to hex ASCII.
;call with AL=binary value
; DI=addr to store string
;returns AX, CX destroyed.
movah,al;save lower nibble.
movcx,4;shift right 4 positions
shral,cl;to get upper nibble.
callascii;convert 4 bits to ASCII equivalent
mov[di],al;store into output string.
moval,ah;get back lower nibble.
andal,0fh
callascii;convert 4 bits to ASCII
mov [di+1],al;and store into output string.
ret;back to caller.
btoaendp
asciiprocnear;convert 4 lower bits of AL
addal,'0';into the equivalent ASCII char.
cmpal,'9';in the range {0...9,A...F}
jleascii2;and return char. in AL.
addal,'A'-'9'-1;"fudge factor" for range A-F.
ascii2:ret;return to caller.
asciiendp
cseg ends
data segment para public 'DATA'
msg1dbcr,lf
db'Failed to open NUL device.'
dbcr,lf,eom
msg2 db cr,lf
db 'Requires DOS version 2 or greater.'
db cr,lf,eom
msg3dbcr,lf
db'End of device chain.'
dbcr,lf,eom
hdrdbcr,lf
db'Addr Attr '
db'Str Int Type Units Name '
dbeom
inf dbcr,lf
inf1db'XXXX:';seg device header
inf2db'XXXX ';offs device header
inf3db'XXXX ';attribute
inf4db'XXXX ';strategy
inf5db'XXXX ';interrupt handler
inf6db'X ';type (block or char)
inf7db'XX ';units (if block device)
inf8db' ';name (if char device)
dbeom
;fcb to open NUL device
nulfcbdb0;drive
db'NUL';name of NUL device
db8 dup (' ')
db25 dup (0)
data ends
stack segment para stack 'STACK'
db 64 dup (?)
stack ends
end dev
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