HPAVC/HPAVC CD-ROM.iso/pc/PCACHSRC.ZIP/DRIVER2.ASM

Assembly Source File | 1990-07-12 | 11.3 KB | 417 lines

    ;DRIVER2.SYS           B.Kauler,89
    ;simple device driver
    ;.....
    code_seg  segment para    public  'code'
    main_proc proc    far
      assume  cs:code_seg,es:code_seg,ds:code_seg
      org 0   ;required for device drivers.
    begin:
    ;...........................................
    ;this area is the DEVICE HEADER....
    next_dev   dd -1      ;no other device drivers
    attribute  dw 8000h   ;character device.
    strategy   dw dev_str ;addr of 1st DOS call.
    interrupt  dw dev_int ;addr of 2nd DOS call.
    dev_name   db "PRN     " ;name of the driver.
    ;...........................................
    ;this is the LOCAL WORKSPACE AREA....
    rh_off   dw ?  ;Request Header offset.
    rh_seg   dw ?  ;Request Header segment.
    messages db 07h
             db "Simple character device driver"
             db 0Dh,0Ah,07h,"$"
    ;...........................................
    ;this is the STRATEGY procedure area...
    dev_str:
        push   ds         ;save DS.
        push   cs         ;to avoid segment
        pop    ds         ;         override.
        mov    rh_seg,es  ;save Req.Header seg.
        mov    rh_off,bx  ;save Req.Head offset.
        pop    ds         ;restore DS.
        ret
    ;..........................................
    ;this is the INTERRUPT procedure.....
    dev_int:
        push    ds      ;save registers.
        push    es      ;       /
        push    ax      ;       /
        push    bx      ;       /
        push    cx      ;       /
        push    dx      ;       /
        push    di      ;       /
        push    si      ;       /
        push   cs       ;to avoid segment
        pop    ds       ;    override.
    ;.......................
    ;I would like to dump the Req.Hdr
    ;to the printer....
        call dump
    ;.......................
    ;I will not assume that the second call to the
    ;driver will still have the addr. of the Req.
    ;Hdr. in ES:BX. Load it from workspace...
        mov     es,rh_seg
        mov     bx,rh_off
    ;.......................
    ;perform branch based on the command passed in
    ;the Request Header...
        mov     al,es:[bx+2] ;get command code.
        cmp     al,0         ;check for zero.
        je      initialise
        cmp     al,8         ;check for o/p
        jne     nogo
        jmp      data_out
    nogo: cmp   al,10   ;check o/p status.
        je      out_status
    ;just return the DONE-bit set in status
    ;byte of Req.Hdr, for these commands....
        cmp al,1
        je  done
        cmp al,2
        je  done
        cmp al,4
        je  done
        cmp al,5
        je  done
        cmp al,6
        je  done
        cmp al,7
        je  done
        cmp al,11
        je  done
        cmp al,13
        je  done
        cmp al,14
        je  done
    ;for any other command,return error...
        jmp     errors
    done:
      mov es:word ptr [bx+3],0100h ;return status.
      jmp finish
    ;......................................
    out_status:
    ;DOS functions that access the printer
    ;most likely check the output status, so I
    ;had better respond to this command....
    ;Bit-9 in the status-word of the Req.Hdr
    ;=0 if not busy. Bit-8 =1 job done....
     mov es:word ptr [bx+3],0100h
     jmp finish
    ;...............
    initialise:
    ;perform required initialisation action...
        mov     dx,offset messages ;message
        mov     ah,9               ;to screen.
        int     21h                ;/
    ;............
      mov es:word ptr [bx+3],0100h ;return status.
    ;............
    ;it seems that DOS will also require to know
    ;where the driver ends....
        mov     ax,offset the_end ;end prog.
        mov es:[bx+14],ax ;break-addr for DOS.
        mov es:[bx+16],cs ;     /
    ;.......................
    ;I would like to display some info about
    ;where this driver starts and ends in
    ;memory...
        push cs
        pop  dx
        mov  di,offset msga
        call hex2asc
        mov  ah,9
        mov  dx,offset msgb
        int  21h
        jmp  goon1
    msgb db "driver loaded at segment "
    msga db "0000h",0Dh,0Ah,"$"
    goon1: mov  dx,offset begin
        mov  di,offset msgc
        call hex2asc
        mov  ah,9
        mov  dx,offset msgd
        int 21h
        jmp goon2
    msgd db "and starting offset :"
    msgc db "0000h",0Dh,0Ah,"$"
    goon2: mov  dx,offset the_end
        mov  di,offset msge
        call hex2asc
        mov  ah,9
        mov  dx,offset msgf
        int 21h
        jmp goon3
    msgf db "and ending offset :"
    msge db "0000h",0Dh,0Ah,"$"
    goon3:
    ;.......................
    ;also I would like to dump the Req.Hdr
    ;to the printer....
        call dump
    ;...................
        jmp finish
    ;.................................
    data_out:
    ;Processing the OUTPUT command...
    ;note that an offset of 13dec from the
    ;beginning of the Req Hdr is the start of
    ;the dynamic portion.
    ;first get the byte count....
      mov cx,es:[bx+18]
    ;now get the data address....
      mov di,es:[bx+14]
      mov ax,es:[bx+16]
      mov es,ax
    ;now transfer the data....
      push bx           ;save BX.
      push es           ;save ES.
      mov bx,0
    next_char:
      mov al,es:[di]
      inc di
      mov ah,0Eh        ;display char.
      int 10h           ;       /
      loop next_char
      pop es            ;restore ES.
      pop bx            ;restore BX.

      mov es:word ptr [bx+3],0100h ;return status.

      jmp finish
    ;..................................
    errors:
      ;put an "E" onto screen....
      push bx
      mov bx,0
      mov ax,0E45h
      int 10h
      pop bx
      mov es:word ptr [bx+3],8103h ;return status
    ;......................................
    finish:
        pop si           ;restore all reg's.
        pop di
        pop dx
        pop cx
        pop bx
        pop ax
        pop es
        pop ds
        ret
    ;......................................
    hex2asc proc near
    ;hex to ascii conversion, for display...
    ;requires DX=binary number,DI=addr.ASCII
    ;string. Returns nothing.
        push cx
        push ax
        mov cx,4
    h1: push cx
        mov  cl,4
        rol  dx,cl
        mov  al,dl
        and  al,0Fh
        cmp  al,0Ah
        jge  h2
        add  al,30h
        jmp  h3
    h2: add  al,37h
    h3: mov  cs:[di],al
        inc  di
        pop  cx
        loop h1
        pop  ax
        pop  cx
        ret
    hex2asc  endp
    ;......................................
    dump proc near
    ;a problem I have had with debugging
    ;these drivers is knowing what DOS has
    ;sent to the driver via the Req. Hdr.
    ;This routine will (hopefully) print out
    ;the contents of the Req.Hdr.
    ;Make sure the printer is turned on and
    ;paper inserted.
        mov  ax,cs:rh_seg
        mov  es,ax
        mov  bx,cs:rh_off
        mov  al,es:[bx+2]  ;get command
        mov  ah,0
        rol  al,1
        mov  di,offset cmtab
        add  di,ax
        mov  ax,[di]
        call prtmsg
        ;display the req.Hdr....
        mov  dl,es:[bx]
        mov  dh,0
        mov  di,offset crh1
        call hex2asc
        mov  dl,es:[bx+1]
        mov dh,0
        mov  di,offset crh2
        call hex2asc
        mov  dl,es:[bx+2]
        mov  dh,0
        mov  di,offset crh3
        call hex2asc
        mov  dx,es:word ptr [bx+3]
        mov  di,offset crh4
        call hex2asc
        mov  ax,offset crh
        call prtmsg
        ;display req hdr unique to each
        ;command...
        mov  al,es:[bx+2]
        cmp  al,0
        jne  d1
    d1: cmp  al,1
        jne  d2
        mov  dl,es:[bx+14]
        mov  dh,0
        mov  di,offset cp1a
        call hex2asc
        mov  ax,offset cp1
        call prtmsg
        jmp  dexit
    d2: cmp  al,2
        jne  d3
    d3: cmp  al,3
        jne  d4
    d4: cmp  al,4
        jne  d5
        mov  dx,es:word ptr [bx+18]
        mov  di,offset cp4a
        call hex2asc
        mov  dx,es:word ptr [bx+20]
        mov  di,offset cp4b
        call hex2asc
        mov  ax,offset cp4
        call prtmsg
        jmp  dexit
    d5: cmp  al,5
        jne  d6
    d6: cmp  al,6
        jne  d7
    d7: cmp  al,7
        jne  d8
    d8: cmp  al,8
        jne  d9
        mov  dx,es:word ptr [bx+18]
        mov  di,offset cp4a
        call hex2asc
        mov  dx,es:word ptr [bx+20]
        mov  di,offset cp4b
        call hex2asc
        mov  ax,offset cp4
        call prtmsg
        jmp  dexit
    d9: cmp  al,9
        jne  da
        mov  dx,es:word ptr [bx+18]
        mov  di,offset cp4a
        call hex2asc
        mov  dx,es:word ptr [bx+20]
        mov  di,offset cp4b
        call hex2asc
        mov  ax,offset cp4
        call prtmsg
        jmp  dexit
    da: cmp  al,0Ah
        jne  dbb
    dbb: cmp al,0Bh
        jne  dc
    dc: cmp  al,0Ch
        jne  ddd
    ddd: cmp al,0Dh
        jne  de
    de: cmp  al,0Eh
        jne  dff
    dff: cmp  al,0Fh
        jne  d10
    d10: cmp al,10h
        jne  dexit
    dexit: ret
    dump   endp
    ;.....
    crh db " len "
    crh1  db "0000",0Dh,0Ah
          db " unit "
    crh2  db "0000",0dh,0ah
          db " cmd "
    crh3  db "0000",0dh,0ah
          db " status "
    crh4  db "0000",0dh,0ah,"$"
    cp1   db " media status "
    cp1a  db "0000",0dh,0ah,"$"
    cp4   db " count "
    cp4a  db "0000",0dh,0ah
          db " start "
    cp4b  db "0000",0dh,0ah,"$"
    cm0   db "initialisation",0dh,0ah,"$"
    cm1   db "media_check   ",0dh,0ah,"$"
    cm2   db "get_bpb       ",0dh,0ah,"$"
    cm3   db "ioctl_in      ",0dh,0ah,"$"
    cm4   db "input         ",0dh,0ah,"$"
    cm5   db "nd_input      ",0dh,0ah,"$"
    cm6   db "input_status  ",0dh,0ah,"$"
    cm7   db "input_flush   ",0dh,0ah,"$"
    cm8   db "output        ",0dh,0ah,"$"
    cm9   db "output_verify ",0dh,0ah,"$"
    cma   db "output_status ",0dh,0ah,"$"
    cmb   db "output_flush  ",0dh,0ah,"$"
    cmcc  db "ioctl_out     ",0dh,0ah,"$"
    cmd   db "open          ",0dh,0ah,"$"
    cme   db "close         ",0dh,0ah,"$"
    cmf   db "removable     ",0dh,0ah,"$"
    cm10  db "output_busy   ",0dh,0ah,"$"
    cmtab label word
          dw cm0
          dw cm1
          dw cm2
          dw cm3
          dw cm4
          dw cm5
          dw cm6
          dw cm7
          dw cm8
          dw cm9
          dw cma
          dw cmb
          dw cmcc
          dw cmd
          dw cme
          dw cmf
          dw cm10
    ;...............
    prtmsg proc near
    ;requires AX=address of string to be
    ;printed. Returns nothing.
        push dx
        push si
        mov  dx,0
        mov  si,ax
    prt1: mov ah,0
        mov  al,[si]
        cmp  al,"$"
        je   prt2
        int  17h
        inc  si
        jmp  prt1
    prt2: pop si
        pop  dx
        ret
    prtmsg endp
    ;....................................
    the_end:
    ;..........................................
    main_proc    endp
    code_seg     ends
                 end    begin
    ;*****end of device driver******
    ;..........................................