PAGE    60, 132

TITLE   HDR     22-Feb-85       Device Driver Header                    |



;-----------------------------------------------------------------------|

;                                                                       |

;       Device Driver Library                                           |

;               Device Driver Header                                    |

;                                                                       |

;-----------------------------------------------------------------------|

;       REVISION HISTORY                                                |

;                                                                       |

; Number    DD-MMM-YY             WHO                   WHY             |

;-------|---------------|-----------------------|-----------------------|

; 0.0   |   22-Feb-85   | Frank Whaley          | Initial Release       |

;-----------------------------------------------------------------------|



        PAGE

;-----------------------------------------------------------------------|

;       Equates                                                         |

;-----------------------------------------------------------------------|



StkSiz  EQU     2048                    ; local stack size



        PAGE

;-----------------------------------------------------------------------|

;       Group Selection                                                 |

;-----------------------------------------------------------------------|



PGROUP  Group   PROG, TAIL

DGROUP  Group   DATA, DTAIL



PROG    Segment Para Public 'PROG'

PROG    EndS



DATA    Segment Para Public 'DATA'      ; define first

DATA    EndS



        Assume  CS:PROG, DS:DATA, ES:DATA, SS:DATA



        PAGE

;-----------------------------------------------------------------------|

;       Program Segment                                                 |

;-----------------------------------------------------------------------|



PROG    Segment Para Public 'PROG'



        Extrn   Init:Near,      MediaChe:Near,  BuildBPB:Near

        Extrn   IoCtlIn:Near,   Input:Near,     ndInput:Near

        Extrn   InputSta:Near,  InputFlu:Near,  Output:Near

        Extrn   OutVerif:Near,  OutStatu:Near,  OutFlush:Near

        Extrn   IoCtlOut:Near,  DevOpen:Near,   DevClose:Near

        Extrn   RemMedia:Near



        ORG     0



HDR     Proc    Far



;-----------------------------------------------------------------------|

;       Device Header                                                   |

;-----------------------------------------------------------------------|



        DD      -1                      ; -> next device

;       DW      theAttribute            ; you must enter attribute field

        DW      8000H                   ; character only device

        DW      Strategy                ; -> device strategy

        DW      Interrupt               ; -> device interrupt

;       DB      theName                 ; you must put something here

        DB      "MON     "              ; mono



;-----------------------------------------------------------------------|

;       Code Segment Variables                                          |

;-----------------------------------------------------------------------|



RHptr   DD      (?)                     ; -> Request Header

ssEntry DW      (?)                     ; entry SS

spEntry DW      (?)                     ; entry SP



        PAGE

;-----------------------------------------------------------------------|

;       Device Strategy                                                 |

;                                                                       |

;       ENTRY : ES:BX -> Request Header                                 |

;                                                                       |

;       EXIT :  Request Header copied to ReqHdr                         |

;               all registers preserved                                 |

;                                                                       |

;-----------------------------------------------------------------------|



Strategy:



        MOV     Word Ptr CS:RHptr,BX    ; save request header ptr

        MOV     Word Ptr CS:RHptr   2,ES



        PUSHF                           ; ( 1) save the world

        PUSH    ES                      ; ( 2)

        PUSH    DS                      ; ( 3)

        PUSH    SI                      ; ( 4)

        PUSH    DI                      ; ( 5)

        PUSH    CX                      ; ( 6)

        PUSH    BX                      ; ( 7)



        MOV     SI,BX

        MOV     BX,ES

        MOV     DS,BX                   ; DS:SI -> Request Header



        MOV     BX,Offset PGROUP:TAIL

        MOV     CL,4

        SHR     BX,CL

        MOV     CX,CS

        ADD     BX,CX

        MOV     ES,BX

        MOV     DI,Offset DGROUP:ReqHdr ; ES:DI -> ReqHdr



        CLD

        XOR     CH,CH

        MOV     CL,[SI]

        REP     MOVSB                   ; copy Request Header



        POP     BX                      ; ( 6) restore

        POP     CX                      ; ( 5)

        POP     DI                      ; ( 4)

        POP     SI                      ; ( 3)

        POP     DS                      ; ( 2)

        POP     ES                      ; ( 1)

        POPF                            ; ( 0)

        RET



        PAGE

;-----------------------------------------------------------------------|

;       Device Interrupt                                                |

;                                                                       |

;       ENTRY : anything                                                |

;                                                                       |

;       EXIT :  all registers preserved                                 |

;                                                                       |

;-----------------------------------------------------------------------|



Interrupt:



        PUSH    DS                      ; ( 1) save the world

        PUSH    ES                      ; ( 2)

        PUSH    AX                      ; ( 3)

        PUSH    BX                      ; ( 4)

        PUSH    CX                      ; ( 5)

        PUSH    DX                      ; ( 6)

        PUSH    SI                      ; ( 7)

        PUSH    DI                      ; ( 8)

        PUSH    BP                      ; ( 9)



        MOV     CS:ssEntry,SS           ; save entry SS

        MOV     CS:spEntry,SP           ; and SP



        MOV     AX,Offset PGROUP:TAIL   ; set our DS, SS, BP, and SP

        MOV     CL,4

        SHR     AX,CL

        MOV     CX,CS

        ADD     AX,CX

        MOV     BX,Offset DGROUP:MyStack

        MOV     DS,AX

        MOV     ES,AX

        MOV     SS,AX

        MOV     SP,BX

        MOV     BP,BX



        ;

        ; call our function

        ;

        MOV     AL,ReqHdr   2           ; AL = Command Code

        SHL     AL,1

        CBW

        MOV     SI,Offset DGROUP:FuncTab

        ADD     SI,AX

        CALL    Word Ptr [SI]



        ;

        ; copy back Request Header

        ;

        LES     DI,RHptr                ; ES:DI -> original space

        MOV     SI,Offset DGROUP:ReqHdr ; DS:SI -> our (updated) copy

        CLD

        XOR     CH,CH

        MOV     CL,[SI]

        REP     MOVSB                   ; copy Request Header



        MOV     SS,CS:ssEntry           ; restore original stuff

        MOV     SP,CS:spEntry



        POP     BP                      ; ( 8) restore

        POP     DI                      ; ( 7)

        POP     SI                      ; ( 6)

        POP     DX                      ; ( 5)

        POP     CX                      ; ( 4)

        POP     BX                      ; ( 3)

        POP     AX                      ; ( 2)

        POP     ES                      ; ( 1)

        POP     DS                      ; ( 0)

        RET



HDR     EndP



PROG    EndS



TAIL    Segment Public 'PROG'           ; for finding end of code segment

TAIL    EndS



        PAGE

;-----------------------------------------------------------------------|

;       Data Segment                                                    |

;-----------------------------------------------------------------------|



DATA    Segment Para Public 'DATA'



        Public  ReqHdr



        DB      StkSiz DUP (?)          ; our stack, overflows into code

MyStack Label   Word



FuncTab Label Word

        DW      Offset PGROUP:Init

        DW      Offset PGROUP:MediaChe

        DW      Offset PGROUP:BuildBPB

        DW      Offset PGROUP:IoCtlIn

        DW      Offset PGROUP:Input

        DW      Offset PGROUP:ndInput

        DW      Offset PGROUP:InputSta

        DW      Offset PGROUP:InputFlu

        DW      Offset PGROUP:Output

        DW      Offset PGROUP:OutVerif

        DW      Offset PGROUP:OutStatu

        DW      Offset PGROUP:OutFlush

        DW      Offset PGROUP:IoCtlOut

        DW      Offset PGROUP:DevOpen

        DW      Offset PGROUP:DevClose

        DW      Offset PGROUP:RemMedia



ReqHdr  DB      256 DUP (?)             ; copy of Request Header



DATA    EndS



DTAIL   Segment Public 'DATA'           ; for finding end of data segment

DTAIL   EndS



        END     HDR                     ; of HDR.ASM