234 lines
7.3 KiB
NASM
234 lines
7.3 KiB
NASM
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;-----------------------------------------------------------------------|
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;
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; Device Driver Library
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; Device Driver Header
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;
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;-----------------------------------------------------------------------|
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PAGE
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;-----------------------------------------------------------------------|
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; Equates
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;-----------------------------------------------------------------------|
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StkSiz EQU 2048 ; local stack size
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PAGE
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;-----------------------------------------------------------------------|
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; Group Selection
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;-----------------------------------------------------------------------|
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PGROUP Group PROG, TAIL
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DGROUP Group DATA, DTAIL
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PROG Segment Para Public 'PROG'
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PROG EndS
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DATA Segment Para Public 'DATA' ; define first
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DATA EndS
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Assume CS:PROG, DS:DATA, ES:DATA, SS:DATA
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PAGE
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;-----------------------------------------------------------------------|
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; Program Segment
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;-----------------------------------------------------------------------|
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PROG Segment Para Public 'PROG'
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Extrn Init:Near, MediaChe:Near, BuildBPB:Near
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Extrn IoCtlIn:Near, Input:Near, ndInput:Near
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Extrn InputSta:Near, InputFlu:Near, Output:Near
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Extrn OutVerif:Near, OutStatu:Near, OutFlush:Near
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Extrn IoCtlOut:Near, DevOpen:Near, DevClose:Near
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Extrn RemMedia:Near
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ORG 0
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HDR Proc Far
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;-----------------------------------------------------------------------|
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; Device Header
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;-----------------------------------------------------------------------|
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DD -1 ; -> next device
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; DW theAttribute ; you must enter attribute field
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DW 8000H ; character only device
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DW Strategy ; -> device strategy
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DW Interrupt ; -> device interrupt
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; DB theName ; you must put something here
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DB "MON " ; mono
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;-----------------------------------------------------------------------|
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; Code Segment Variables
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;-----------------------------------------------------------------------|
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RHptr DD (?) ; -> Request Header
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ssEntry DW (?) ; entry SS
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spEntry DW (?) ; entry SP
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PAGE
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;-----------------------------------------------------------------------|
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; Device Strategy
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;
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; ENTRY : ES:BX -> Request Header
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;
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; EXIT : Request Header copied to ReqHdr
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; all registers preserved
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;
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;-----------------------------------------------------------------------|
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Strategy:
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MOV Word Ptr CS:RHptr,BX ; save request header ptr
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MOV Word Ptr CS:RHptr + 2,ES
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PUSHF ; (+1) save the world
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PUSH ES ; (+2)
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PUSH DS ; (+3)
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PUSH SI ; (+4)
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PUSH DI ; (+5)
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PUSH CX ; (+6)
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PUSH BX ; (+7)
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MOV SI,BX
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MOV BX,ES
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MOV DS,BX ; DS:SI -> Request Header
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MOV BX,Offset PGROUP:TAIL
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MOV CL,4
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SHR BX,CL
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MOV CX,CS
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ADD BX,CX
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MOV ES,BX
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MOV DI,Offset DGROUP:ReqHdr ; ES:DI -> ReqHdr
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CLD
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XOR CH,CH
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MOV CL,[SI]
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REP MOVSB ; copy Request Header
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POP BX ; (+6) restore
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POP CX ; (+5)
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POP DI ; (+4)
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POP SI ; (+3)
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POP DS ; (+2)
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POP ES ; (+1)
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POPF ; (+0)
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RET
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PAGE
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;-----------------------------------------------------------------------|
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; Device Interrupt
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;
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; ENTRY : anything
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;
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; EXIT : all registers preserved
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;
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;-----------------------------------------------------------------------|
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Interrupt:
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PUSH DS ; (+1) save the world
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PUSH ES ; (+2)
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PUSH AX ; (+3)
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PUSH BX ; (+4)
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PUSH CX ; (+5)
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PUSH DX ; (+6)
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PUSH SI ; (+7)
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PUSH DI ; (+8)
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PUSH BP ; (+9)
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MOV CS:ssEntry,SS ; save entry SS
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MOV CS:spEntry,SP ; and SP
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MOV AX,Offset PGROUP:TAIL ; set our DS, SS, BP, and SP
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MOV CL,4
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SHR AX,CL
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MOV CX,CS
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ADD AX,CX
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MOV BX,Offset DGROUP:MyStack
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MOV DS,AX
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MOV ES,AX
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MOV SS,AX
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MOV SP,BX
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MOV BP,BX
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;
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; call our function
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;
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MOV AL,ReqHdr + 2 ; AL = Command Code
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SHL AL,1
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CBW
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MOV SI,Offset DGROUP:FuncTab
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ADD SI,AX
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CALL Word Ptr [SI]
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;
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; copy back Request Header
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;
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LES DI,RHptr ; ES:DI -> original space
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MOV SI,Offset DGROUP:ReqHdr ; DS:SI -> our (updated) copy
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CLD
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XOR CH,CH
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MOV CL,[SI]
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REP MOVSB ; copy Request Header
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MOV SS,CS:ssEntry ; restore original stuff
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MOV SP,CS:spEntry
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POP BP ; (+8) restore
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POP DI ; (+7)
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POP SI ; (+6)
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POP DX ; (+5)
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POP CX ; (+4)
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POP BX ; (+3)
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POP AX ; (+2)
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POP ES ; (+1)
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POP DS ; (+0)
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RET
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HDR EndP
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PROG EndS
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TAIL Segment Public 'PROG' ; for finding end of code segment
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TAIL EndS
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PAGE
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;-----------------------------------------------------------------------|
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; Data Segment
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;-----------------------------------------------------------------------|
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DATA Segment Para Public 'DATA'
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Public ReqHdr
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DB StkSiz DUP (?) ; our stack, overflows into code
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MyStack Label Word
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FuncTab Label Word
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DW Offset PGROUP:Init
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DW Offset PGROUP:MediaChe
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DW Offset PGROUP:BuildBPB
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DW Offset PGROUP:IoCtlIn
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DW Offset PGROUP:Input
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DW Offset PGROUP:ndInput
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DW Offset PGROUP:InputSta
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DW Offset PGROUP:InputFlu
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DW Offset PGROUP:Output
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DW Offset PGROUP:OutVerif
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DW Offset PGROUP:OutStatu
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DW Offset PGROUP:OutFlush
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DW Offset PGROUP:IoCtlOut
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DW Offset PGROUP:DevOpen
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DW Offset PGROUP:DevClose
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DW Offset PGROUP:RemMedia
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ReqHdr DB 256 DUP (?) ; copy of Request Header
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DATA EndS
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DTAIL Segment Public 'DATA' ; for finding end of data segment
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DTAIL EndS
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END HDR ; of HDR.ASM
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