.model tiny
.486
smart
.code
org 0100h
start:
jmp tsr
db 'LPT'
Tsr:
cli
cmp ax,1234h
jne nomore
mov ax,4321h
jmp itsok
nomore:
push bx
mov bl,ah
xor bh,bh
shl bx,1
mov bx,cs:[bx].tables
mov cs:current,bx
pop bx
call cs:current
itsok:
jnc noerror
push bp
mov bp,sp
or byte ptr [bp+6],1b
pop bp
mov ax,cs
shl eax,16
mov ax,cs:current
jmp endofint
noerror:
push bp
mov bp,sp
and byte ptr [bp+6],0FEh
pop bp
endofint:
sti
iret
current dw 0
tables   dw getlptin
         dw getlptout
         dw getlptinout
         dw setlptin
         dw setlptout
         dw setlptinout
         dw getlpt
         dw getfirstlpt
         dw setemettor
         dw setreceptor
         dw settimeout
         dw gettimeout
         dw receivelpt
         dw sendlpt
         dw receivelptblock
         dw sendlptblock
         dw receivecommand
         dw sendcommand

;envois une commande al
sendcommand:
push ax bx cx di 
mov bl,al
xor bh,bh
shl bx,1
add bx,offset cmde
call cs:[bx]
pop di cx bx ax
ret
cmde  dw nothing
      dw getram

;recupŠre la ram en ds:si de cx distant caractŠres en es:di local
getram:
push ax bx cx ds
mov bx,offset command
mov cs:[bx+2],ds
mov cs:[bx],si
mov cs:[bx+4],cx
push cs
pop ds
mov si,bx
mov cx,6
call sendlptblock
call receivelptblock
pop ds cx bx ax
ret

;Re‡ois une commande et l'execute
Receivecommand:
push ax bx cx di es
push cs
pop es
mov di,offset command
call receivelptblock
mov bl,al
xor bh,bh
shl bx,1
add bx,offset cmd
call cs:[bx]
pop es di cx bx ax
ret
command db 25 dup (0)
cmd dw nothings
    dw sendram

nothings:
ret

Sendram:
push ax cx si ds
mov si,es:[di]
mov ax,es:[di+2]
mov ds,ax
mov cx,es:[di+4]
call sendlptblock
pop ds si cx ax
ret


;---------Segment Adress-----------
Bios equ 040h
;---------Offset Adress------------
Lptadr equ 008h
Timer equ 06Ch
;---------Constant-----------------
onesec equ 18
tensec equ 182
Ack equ 00
Nack equ 0FFh
maxtry equ 10
tokenstart equ 0
tokennext equ 1
tokenstop equ 2  
tokenbad equ 3
tokenresend equ 4


Initlpt:
push ax ecx
call StartTimer
cmp emettor,0
je receptinit
mov al,10000b
call SetLptOut
waitinit1:
call EndTimer
cmp cx,cs:timeout
ja errorinit
call getlptIn
cmp al,00000b
jnz waitinit1
jmp endinit
receptinit:
call EndTimer
cmp cx,cs:timeout
ja errorinit
call getlptIn
cmp al,00000b
jnz receptinit
mov al,10000b
call SetLptOut
endinit:
clc
pop ecx ax
ret
errorinit:
stc
pop ecx ax   
ret


;-Envoie DL       (dh)    JNE si problŠme  JNC error timeout
Sendlpt:
push ax bx ecx
call StartTimer
mov dh,dl
mov al,dl
and al,0Fh
call SetLptOut
waitSend:
call EndTimer
cmp cx,cs:timeout
ja errorsend
call getlptIn
bt ax,4
jnc waitsend
and al,0Fh
mov bl,al
call StartTimer  ;/////
mov al,dh
shr al,4
or al,10000b
call SetLptOut
waitSend2:
call EndTimer
cmp cx,cs:timeout
ja errorsend
call getlptIn
bt ax,4
jc waitsend2
and al,0Fh
shl al,4
add bl,al
cmp dl,bl
pop ecx bx ax
clc
ret
errorsend:
pop ecx bx ax
stc
ret


;-Re‡ois DL       (dh)   
Receivelpt:
push ax bx ecx 
call StartTimer
waitreceive:
call EndTimer
cmp cx,cs:timeout
ja errorreceive
call getlptIn
bt ax,4
jnc waitreceive
and al,0Fh
mov dl,al
call SetLptOut
call StartTimer  ;/////
waitreceive2:
call EndTimer
cmp cx,cs:timeout
ja errorreceive
call getlptIn
bt ax,4
jc waitreceive2
and al,0Fh
mov dh,al
shl dh,4
add dl,dh
or al,10000b
call SetlptOut
clc
pop ecx bx ax
ret
errorreceive:
stc
pop ecx bx ax 
ret

;-AX
SetTimeout:
mov cs:Timeout,dx
ret

timeout dw tensec

getTimeout:
mov dx,cs:Timeout
ret    

SetEmettor:
mov cs:Emettor,1
ret 
    
Emettor db 0

SetReceptor:
mov cs:Emettor,0
ret

;->bx  Nøport->Adresse dx 
GetLpt:
push ax bx ds
mov ax,bios
mov ds,ax
dec bx
shl bx,1
mov dx,ds:[Lptadr+bx]
mov cs:lpt,dx
pop ds bx ax
ret
lpt dw 0

;->bx  Nøport->Adresse dx
GetFirstLpt:
push ax ds
mov ax,bios
mov ds,ax
xor bx,bx
findlpt:
mov dx,ds:[Lptadr+bx]
cmp dx,0
jne oklpt
add bx,2
cmp bx,4
jbe findlpt
oklpt:
mov cs:lpt,dx
pop ds ax
ret

;->
StartTimer:
push ax ecx ds
mov ax,Bios
mov ds,ax
mov ecx,ds:[timer]
mov cs:times,ecx
pop ds ecx ax
ret
times dd 0

;->Ecx time elapsed
EndTimer:
push ax ds
mov ax,Bios
mov ds,ax
mov ecx,ds:[timer]
sub ecx,cs:times
mov ecx,0
pop ds ax
ret

;->
GetLptOut:
push dx
mov dx,cs:lpt
in al,dx
pop dx
ret

GetLptIn:
push dx
mov dx,cs:lpt
inc dx
in al,dx
shr al,3
pop dx
ret

GetLptInOut:
push dx
mov dx,cs:lpt
add dx,2
in al,dx
and al,11111b
pop dx
ret

SetLptOut:
push dx
mov dx,cs:lpt
out dx,al
pop dx
ret

SetLptIn:
push dx
mov dx,cs:lpt
inc dx
out dx,al
pop dx
ret

SetLptInOut:
push dx
mov dx,cs:lpt
add dx,2
out dx,al
pop dx
ret

;R‚alise un checksum 8 bits sur donn‚es DS:SI, nb CX r‚sultat dans dl
Checksum8:
push cx si 
check:
add dl,[si]
inc si
dec cx
jnz check
pop si cx
ret

;DS:SI pointeur sur donn‚es, CX nombres de donn‚es, AL token
SendLptBlock:
push ax bx cx edx si edi bp
mov dx,cx
shl edx,16
mov dh,al
call checksum8
mov edi,edx
xor dh,dh
mov bp,dx
mov ah,maxtry
retry:
mov bl,4
xor al,al
header:
mov dx,di
call sendlpt
setne al
jc outt
rol edi,8
dec bl
jnz header
cmp al,0
jne notgood
mov dl,ACK
jmp allsend
notgood:
mov dl,NACK
allsend:
call sendlpt
setne al
jc outt
cmp al,0
je okheader
dec ah
jnz retry
jmp outt
okheader:
cmp cx,0
je endoftrans
mov di,maxtry
retry2:
mov bx,cx
xor ax,ax
body:
mov dl,[si+bx-1]
add ah,dl
call sendlpt
setne al
jc outt
dec bx
jnz body
cmp al,0
jne notgood2
mov dl,ACK
jmp allisend
notgood2:
mov dl,NACK
allisend:
call sendlpt
setne al
jc outt
cmp al,0
je endoftrans
dec di
jnz retry2
outt:
stc
endoftrans:
mov al,ah
xor ah,ah
cmp bp,ax
pop bp edi si edx cx bx ax
ret

;Receptionne en es:di les donn‚es au nombres de CX token AL   (AH)  (ECX)
receiveLptBlock:
push bx dx si bp
mov ah,maxtry
retrye:
mov bl,4
headere:
call receivelpt
jc outte
mov cl,dl
rol ecx,8
dec bl
jnz headere
call receivelpt
jc outte
cmp dl,ACK
je okheadere
dec ah
jnz retrye
jmp outte
okheadere:
mov al,ch
xor ch,ch
mov bp,cx
rol ecx,16
cmp cx,0
je endoftranse
mov si,maxtry
retrye2:
mov bx,cx
xor ah,ah
bodye:
call receivelpt
jc outte
mov es:[di+bx-1],dl
add ah,dl
dec bx
jnz bodye
call receivelpt
jc outte
cmp dl,ACK
je endoftranse
dec si
jnz retrye2
outte:
stc
endoftranse:
mov bl,ah
xor bh,bh
cmp bp,bx
pop bp si dx bx 
ret               
end start