mirror of
https://github.com/microsoft/MS-DOS.git
synced 2024-12-01 18:15:47 +00:00
439 lines
12 KiB
NASM
439 lines
12 KiB
NASM
;
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; Device call routines for MSDOS
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;
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INCLUDE DOSSEG.ASM
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IFNDEF KANJI
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KANJI EQU 0 ;FALSE
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ENDIF
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CODE SEGMENT BYTE PUBLIC 'CODE'
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ASSUME SS:DOSGROUP,CS:DOSGROUP
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.xlist
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.xcref
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INCLUDE DOSSYM.ASM
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INCLUDE DEVSYM.ASM
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.cref
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.list
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TITLE DEV - Device call routines
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NAME Dev
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i_need IOXAD,DWORD
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i_need IOSCNT,WORD
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i_need DEVIOBUF,4
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i_need IOCALL,BYTE
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i_need IOMED,BYTE
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i_need IORCHR,BYTE
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i_need CALLSCNT,WORD
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i_need DMAAdd,DWORD
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i_need NullDevPt,DWORD
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i_need CallDevAd,DWORD
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i_need Attrib,BYTE
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i_need NULDEV,DWORD
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i_need Name1,BYTE
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i_need DevPt,DWORD
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i_need DPBHead,DWORD
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i_need NumIO,BYTE
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i_need ThisDPB,DWORD
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i_need DevCall,DWORD
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i_need VerFlg,BYTE
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SUBTTL IOFUNC -- DO FUNCTION 1-12 I/O
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PAGE
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IOFUNC_RETRY:
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ASSUME DS:NOTHING,ES:NOTHING
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invoke restore_world
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procedure IOFUNC,NEAR
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ASSUME DS:NOTHING,ES:NOTHING
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; Inputs:
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; DS:SI Points to FCB
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; AH is function code
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; = 0 Input
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; = 1 Input Status
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; = 2 Output
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; = 3 Output Status
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; = 4 Flush
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; AL = character if output
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; Function:
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; Perform indicated I/O to device or file
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; Outputs:
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; AL is character if input
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; If a status call
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; zero set if not ready
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; zero reset if ready (character in AL for input status)
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; For regular files:
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; Input Status
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; Gets character but restores fcb_RR field
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; Zero set on EOF
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; Input
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; Gets character advances fcb_RR field
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; Returns ^Z on EOF
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; Output Status
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; Always ready
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; AX altered, all other registers preserved
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MOV WORD PTR [IOXAD+2],SS
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MOV WORD PTR [IOXAD],OFFSET DOSGROUP:DEVIOBUF
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MOV WORD PTR [IOSCNT],1
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MOV WORD PTR [DEVIOBUF],AX
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IOFUNC2:
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TEST [SI.fcb_DEVID],080H
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JNZ IOTODEV
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JMP IOTOFILE
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IOTODEV:
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invoke save_world
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PUSH DS
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PUSH SS
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POP ES
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PUSH SS
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POP DS
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ASSUME DS:DOSGROUP
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XOR BX,BX
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MOV [IOCALL.REQSTAT],BX
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MOV BYTE PTR [IOMED],BL
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MOV BX,OFFSET DOSGROUP:IOCALL
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MOV CX,(DEVRD SHL 8) OR DRDWRHL
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OR AH,AH
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JZ DCALLR
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MOV CX,(DEVRDND SHL 8) OR DRDNDHL
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DEC AH
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JZ DCALLR
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MOV CX,(DEVWRT SHL 8) OR DRDWRHL
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DEC AH
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JZ DCALLO
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MOV CX,(DEVOST SHL 8) OR DSTATHL
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DEC AH
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JZ DCALLO
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DFLUSH:
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MOV CX,(DEVIFL SHL 8) OR DFLSHL
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DCALLR:
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MOV AH,86H
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DCALL:
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MOV [IOCALL.REQLEN],CL
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MOV [IOCALL.REQFUNC],CH
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MOV CL,AH
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POP DS
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ASSUME DS:NOTHING
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CALL DEVIOCALL
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MOV DI,[IOCALL.REQSTAT]
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TEST DI,STERR
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JZ OKDEVIO
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MOV AH,CL
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invoke CHARHARD
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CMP AL,1
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JZ IOFUNC_RETRY
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;Know user must have wanted ignore. Make sure device shows ready so
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;that DOS doesn't get caught in a status loop when user simply wants
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;to ignore the error.
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AND BYTE PTR [IOCALL.REQSTAT+1], NOT (STBUI SHR 8)
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OKDEVIO:
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PUSH SS
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POP DS
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ASSUME DS:DOSGROUP
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CMP CH,DEVRDND
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JNZ DNODRD
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MOV AL,BYTE PTR [IORCHR]
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MOV [DEVIOBUF],AL
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DNODRD: MOV AH,BYTE PTR [IOCALL.REQSTAT+1]
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NOT AH ; Zero = busy, not zero = ready
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AND AH,STBUI SHR 8
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invoke restore_world
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ASSUME DS:NOTHING
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MOV AX,WORD PTR [DEVIOBUF]
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return
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DCALLO:
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MOV AH,87H
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JMP SHORT DCALL
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IOTOFILE:
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ASSUME DS:NOTHING
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OR AH,AH
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JZ IOIN
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DEC AH
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JZ IOIST
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DEC AH
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JZ IOUT
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return ; NON ZERO FLAG FOR OUTPUT STATUS
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IOIST:
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PUSH WORD PTR [SI.fcb_RR] ; Save position
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PUSH WORD PTR [SI.fcb_RR+2]
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CALL IOIN
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POP WORD PTR [SI.fcb_RR+2] ; Restore position
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POP WORD PTR [SI.fcb_RR]
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return
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IOUT:
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CALL SETXADDR
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invoke STORE
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invoke FINNOSAV
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CALL RESTXADDR ; If you change this into a jmp don't come
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return ; crying to me when things don't work ARR
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IOIN:
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CALL SETXADDR
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invoke LOAD
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PUSH CX
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invoke FINNOSAV
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POP CX
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OR CX,CX ; Check EOF
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CALL RESTXADDR
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MOV AL,[DEVIOBUF] ; Get byte from trans addr
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retnz
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MOV AL,1AH ; ^Z if EOF
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return
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SETXADDR:
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POP WORD PTR [CALLSCNT] ; Return address
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invoke save_world
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PUSH WORD PTR [DMAADD] ; Save Disk trans addr
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PUSH WORD PTR [DMAADD+2]
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PUSH DS
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PUSH SS
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POP DS
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ASSUME DS:DOSGROUP
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MOV CX,WORD PTR [IOXAD+2]
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MOV WORD PTR [DMAADD+2],CX
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MOV CX,WORD PTR [IOXAD]
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MOV WORD PTR [DMAADD],CX ; Set byte trans addr
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MOV CX,[IOSCNT] ; ioscnt specifies length of buffer
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POP DS
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ASSUME DS:NOTHING
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MOV [SI.fcb_RECSIZ],1 ; One byte per record
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MOV DX,SI ; FCB to DS:DX
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invoke GETRRPOS
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JMP SHORT RESTRET ; RETURN ADDRESS
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RESTXADDR:
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POP WORD PTR [CALLSCNT] ; Return address
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POP WORD PTR [DMAADD+2] ; Restore Disk trans addr
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POP WORD PTR [DMAADD]
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invoke restore_world
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RESTRET:JMP WORD PTR [CALLSCNT] ; Return address
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IOFUNC ENDP
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SUBTTL DEVIOCALL, DEVIOCALL2 - CALL A DEVICE
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PAGE
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procedure DEVIOCALL,NEAR
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ASSUME DS:NOTHING,ES:NOTHING
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; Inputs:
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; DS:SI Points to device FCB
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; ES:BX Points to request data
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; Function:
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; Call the device
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; Outputs:
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; None
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; DS:SI,AX destroyed, others preserved
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LDS SI,DWORD PTR [SI.fcb_FIRCLUS]
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entry DEVIOCALL2
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; As above only DS:SI points to device header on entry, and DS:SI is preserved
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MOV AX,[SI.SDEVSTRAT]
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MOV WORD PTR [CALLDEVAD],AX
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MOV WORD PTR [CALLDEVAD+2],DS
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CALL DWORD PTR [CALLDEVAD]
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MOV AX,[SI.SDEVINT]
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MOV WORD PTR [CALLDEVAD],AX
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CALL DWORD PTR [CALLDEVAD]
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return
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DEVIOCALL ENDP
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SUBTTL DEVNAME - LOOK FOR NAME OF DEVICE
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PAGE
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procedure DEVNAME,NEAR
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ASSUME DS:DOSGROUP,ES:DOSGROUP
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; Inputs:
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; DS,ES:DOSGROUP
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; Filename in NAME1
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; Function:
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; Determine if file is in list of I/O drivers
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; Outputs:
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; Carry set if name not found
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; ELSE
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; Zero flag set
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; BH = Bit 7,6 = 1, bit 5 = 0 (cooked mode)
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; bits 0-4 set from low byte of attribute word
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; DEVPT = DWORD pointer to Device header of device
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; Registers BX destroyed
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PUSH SI
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PUSH DI
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PUSH CX
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IF KANJI
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PUSH WORD PTR [NAME1]
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CMP [NAME1],5
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JNZ NOKTR
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MOV [NAME1],0E5H
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NOKTR:
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ENDIF
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TEST BYTE PTR [ATTRIB],attr_volume_id ; If looking for VOL id don't find devs
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JNZ RET31
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MOV SI,OFFSET DOSGROUP:NULDEV
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LOOKIO:
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ASSUME DS:NOTHING
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TEST [SI.SDEVATT],DEVTYP
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JZ SKIPDEV ; Skip block devices
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PUSH SI
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ADD SI,SDEVNAME
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MOV DI,OFFSET DOSGROUP:NAME1
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MOV CX,4 ; All devices are 8 letters
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REPE CMPSW ; Check for name in list
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POP SI
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JZ IOCHK ; Found it?
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SKIPDEV:
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LDS SI,DWORD PTR [SI] ; Get address of next device
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CMP SI,-1 ; At end of list?
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JNZ LOOKIO
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RET31: STC ; Not found
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RETNV: PUSH SS
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POP DS
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ASSUME DS:DOSGROUP
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IF KANJI
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POP WORD PTR [NAME1]
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ENDIF
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POP CX
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POP DI
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POP SI
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RET
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IOCHK:
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ASSUME DS:NOTHING
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MOV WORD PTR [DEVPT+2],DS ; Save pointer to device
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MOV BH,BYTE PTR [SI.SDEVATT]
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OR BH,0C0H
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AND BH,NOT 020H ;Clears Carry
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MOV WORD PTR [DEVPT],SI
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JMP RETNV
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DevName ENDP
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procedure GetBP,NEAR
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ASSUME DS:DOSGROUP,ES:NOTHING
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; Inputs:
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; AL = Logical unit number (A = 0)
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; Function:
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; Find Drive Parameter Block
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; Outputs:
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; ES:BP points to DPB
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; [THISDPB] = ES:BP
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; Carry set if unit number bad
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; No other registers altered
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LES BP,[DPBHEAD] ; Just in case drive isn't valid
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AND AL,3FH ; Mask out dirty and device bits
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CMP AL,BYTE PTR [NUMIO]
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CMC
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JC GOTDPB ; Get drive A
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FNDDPB:
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CMP AL,ES:[BP.dpb_drive]
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JZ GOTDPB ; Carry is clear if jump executed
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LES BP,ES:[BP.dpb_next_dpb]
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JMP SHORT FNDDPB
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GOTDPB:
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MOV WORD PTR [THISDPB],BP
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MOV WORD PTR [THISDPB+2],ES
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RET
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GetBP ENDP
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SUBTTL SETREAD, SETWRITE -- SET UP HEADER BLOCK
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PAGE
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procedure SETREAD,NEAR
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ASSUME DS:NOTHING,ES:NOTHING
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; Inputs:
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; DS:BX = Transfer Address
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; CX = Record Count
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; DX = Starting Record
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; AH = Media Byte
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; AL = Unit Code
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; Function:
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; Set up the device call header at DEVCALL
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; Output:
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; ES:BX Points to DEVCALL
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; No other registers effected
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PUSH DI
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PUSH CX
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PUSH AX
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MOV CL,DEVRD
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SETCALLHEAD:
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MOV AL,DRDWRHL
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PUSH SS
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POP ES
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MOV DI,OFFSET DOSGROUP:DEVCALL
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STOSB ; length
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POP AX
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STOSB ; Unit
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PUSH AX
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MOV AL,CL
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STOSB ; Command code
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XOR AX,AX
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STOSW ; Status
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ADD DI,8 ; Skip link fields
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POP AX
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XCHG AH,AL
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STOSB ; Media byte
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XCHG AL,AH
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PUSH AX
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MOV AX,BX
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STOSW
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MOV AX,DS
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STOSW ; Transfer addr
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POP CX ; Real AX
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POP AX ; Real CX
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STOSW ; Count
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XCHG AX,DX ; AX=Real DX, DX=real CX, CX=real AX
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STOSW ; Start
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XCHG AX,CX
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XCHG DX,CX
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POP DI
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MOV BX,OFFSET DOSGROUP:DEVCALL
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RET
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entry SETWRITE
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ASSUME DS:NOTHING,ES:NOTHING
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; Inputs:
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; DS:BX = Transfer Address
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; CX = Record Count
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; DX = Starting Record
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; AH = Media Byte
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; AL = Unit Code
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; Function:
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; Set up the device call header at DEVCALL
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; Output:
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; ES:BX Points to DEVCALL
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; No other registers effected
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PUSH DI
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PUSH CX
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PUSH AX
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MOV CL,DEVWRT
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ADD CL,[VERFLG]
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JMP SHORT SETCALLHEAD
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SETREAD ENDP
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do_ext
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CODE ENDS
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END
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