Power-Programmierung/CD1.mdf/assemblr/library/devdriv/ddd/scrolock.asm

Assembly Source File | 1989-04-19 | 8.7 KB | 345 lines

    PAGE    ,132

CSEG    SEGMENT
    ASSUME    CS:CSEG, DS:NOTHING, ES:NOTHING
    ORG    0000H            ; For all device drivers

Header    DD    -1            ; One device
    DW    08000H            ; Character device
StratA    DW    Strat            ; Strategy entrance
IntrA    DW    Intr            ; Interrupt entrance
    DB    'Scrolock'        ; 8 character dummy name

;    Note: Put resident part of DDD here.
    TITLE    SCROLOCK -- Holds screen every page

COMMENT    $
    SCROLOCK.COM -- Locks scrolling of screen

    Generate EXE file using the following commands:
    MASM SCROLOCK;
    LINK SCROLOCK;

    Load from CONFIG.SYS file by use of the command:
    DEVICE=SCROLOCK.EXE followed by an optional line count
    and an optional keyword ON. If no line count is given,
    the CGA normal line count of 25 will be used. If the
    keyword ON is used, Scroll-Lock will be turned on.

    Load at system command or from within AUTOEXEC.BAT.
    Type: SCROLOCK followed by an optional line count and
    an optional keyword ON. If no line count is given, the
    CGA normal line count of 25 will be used. If the keyword
    ON is used, Scroll-Lock will be turned on.

    To use, toggle the Scroll-Lock key to activate and
    deactivate. If active, screen will fill to the bottom
    line, will scroll until the line where the cursor was is
    at the top and then the screen will freeze with the
    cursor in the bottom left corner. To get the next
    screen-full, hit any key. Note: The key will be
    used later, so if you want just another screen-full,
    hit the Ctrl, Alt or either Shift key.

    If your CONFIG.SYS file contains the line
    DEVICE=ANSI.SYS
    you MUST change ANSI.SYS with these instructions:

    DEBUG ANSI.SYS
    E 29D 90 90
    E 2A1 90 90
    W
    Q

    $

;    All Data
;    --------

DATA        SEGMENT AT 00040H    ; ROM-BIOS Data area
        ORG    00017H
KB_FLAG        DB    ?
SCROLL_STATE    EQU    010H
DATA        ENDS

OldIntr09    DW    ?        ; Interrupt vector storage
        DW    ?
OldIntr10    DW    ?
        DW    ?
LineCount    DB    ?        ; Line counter
ActPage        DB    ?        ; Active page (0 usually)
MaxRows        DB    25        ; Maximum screen rows

COMMENT    $
    If your screen has more than 25 lines, enter the
    correct number on the command line after SCROLOCK.
    You may use SCROLOCK for each screen length you have
    available on your video board. Otherwise, don't load
    SCROLOCK more than once.
    $

;    Intercept of Interrupt 10H -- BIOS Video Call
;    ---------------------------------------------

NewIntr10:
    STI                ; Allow interrupts
    PUSH    DS            ; Save registers
    PUSH    AX
    PUSH    CS            ; Set DS = CS
    POP    DS
    ASSUME    DS:CSEG
    CMP    AH,005H            ; Change active page?
    JE    SetPage            ; Yes, save page
    CMP    AH,000H            ; Change video mode?
    JE    ClrScrAndPage        ; Yes, stop at bottom
    CMP    AX,00600H        ; Clear video screen?
    JE    ClrScr            ; Yes, stop at bottom
    CMP    AX,00601H        ; Roll up one line?
    JNE    ExitIntr10        ; No, exit
    CMP    CX,000H            ; From first line?
    JNE    ExitIntr10        ; No, exit
    MOV    AL,MaxRows
    CMP    DH,AL            ; To last line?
    JNE    ExitIntr10        ; No, exit
    PUSH    DS            ; Yes, set up for keyboard
    MOV    AX,SEG DATA        ; status check in low
    MOV    DS,AX            ; memory 0040:0017
    ASSUME    DS:DATA
    TEST    KB_FLAG,SCROLL_STATE
    POP    DS            ; Scroll-Lock locked?
    ASSUME    DS:CSEG
    JZ    ExitIntr10        ; No, not locked
    INC    LineCount        ; Yes, now count lines
    MOV    AL,MaxRows        ; Overflow point
LoopUntil:
    CMP    LineCount,AL        ; Maximum roll?
    JA    LoopUntil        ; Yes, loop until key pressed
    JMP    SHORT ExitIntr10    ; No, roll some more

ClrScrAndPage:
    MOV    ActPage,000H        ; Reset page zero
ClrScr:
    MOV    AL,MaxRows
    MOV    LineCount,AL        ; Do not allow any roll
    JMP    SHORT ExitIntr10

SetPage:
    MOV    ActPage,AL        ; Save new page
ExitIntr10:
    POP    AX            ; Restore registers
    POP    DS
    JMP    DWORD PTR CS:OldIntr10    ; Perform video request

;    Intercept of Interrupt 9H -- Hardware Keyboard
;    ----------------------------------------------

NewIntr09:
    ASSUME    DS:NOTHING
    PUSH    AX            ; Save registers
    PUSH    BX
    PUSH    CX
    PUSH    DX
    STI                ; Allow interrupts
    IN    AL,060H            ; Read scan code
    TEST    AL,080H            ; Key pressed?
    JNE    ExitIntr09        ; No, exit
    MOV    AH,003H            ; Yes, get cursor line
    MOV    BH,ActPage        ; for this page
    INT    010H
    MOV    AH,MaxRows        ; Calculate rows to bottom
    SUB    AH,DH
    MOV    LineCount,AH        ; Allow roll again
ExitIntr09:
    POP    DX            ; Restore registers
    POP    CX
    POP    BX
    POP    AX
    JMP    DWORD PTR CS:OldIntr09    ; Perform keyboard request

IOPacket    STRUC
IO_CMDLEN    DB    ?
IO_UNIT        DB    ?
IO_CMD        DB    ?
IO_STATUS    DW    ?
        DB    8 DUP(?)
IO_MEDIA    DB    ?
IO_ADDRESS    DW    ?
        DW    ?
IO_COUNT    DW    ?
IO_START    DW    ?
IOPacket    ENDS

Init    PROC    FAR
    ASSUME    DS:NOTHING, ES:NOTHING

Packet    DD    0            ; Request packet address

Strat:
    MOV    WORD PTR Packet,BX    ; Save Packet info
    MOV    WORD PTR Packet+2,ES
    RET

Intr:
    PUSH    BX            ; Save registers
    PUSH    DS

;    Note: Put initialization code here.
;    Save all registers used except DS & BX.
;    After code, restore same registers and
;    JMP to "Exit".

;    Initialization Procedure
;    ------------------------

    PUSH    AX            ; Save registers used
    PUSH    DX
    PUSH    ES
    PUSH     SI
    LDS    BX,DWORD PTR Packet
    LDS    SI,DWORD PTR [BX+IO_COUNT]
    SUB    BX,BX            ; Zero counter
Bypass:
    LODSB                ; Get CMD character
    CMP    AL,00DH            ; CR code?
    JE    Install            ; Yes, done with analysis
    CMP    AL,00AH            ; LF code?
    JE    Install            ; Yes, done with analysis
    CMP    AL,01AH            ; EOF code?
    JE    Install            ; Yes, done with analysis
    CALL    Delimit            ; Is it a delimiter?
    JNE    Bypass            ; No, skip garbage
CommandLoop:
    LODSB                ; Get a character
    CMP    AL,00DH            ; CR code?
    JE    Install            ; Yes, done with analysis
    CMP    AL,00AH            ; LF code?
    JE    Install            ; Yes, done with analysis
    CMP    AL,01AH            ; EOF code?
    JE    Install            ; Yes, done with analysis
    CMP    AL,'0'            ; Below digits?
    JB    CommandLoop        ; Yes, ignore all
    CMP    AL,'9'            ; Within digits?
    JNA    Digits            ; Yes, accumulate count
    AND    AL,NOT 020H        ; Translate lower case
    CMP    AL,'N'            ; N of ON?
    JNE    CommandLoop        ; No, ignore all
    PUSH    DS            ; Yes, set Scroll-Lock
    MOV    AX,SEG DATA        ; bit in low
    MOV    DS,AX            ; memory 0040:0017
    ASSUME    DS:DATA
    OR    KB_FLAG,SCROLL_STATE
    POP    DS
    ASSUME    DS:CSEG
    JMP    CommandLoop        ; and look for more

Digits:
    SUB    AL,'0'            ; Convert to value
    SHL    BL,1            ; Multiply BL by 10
    ADD    AL,BL            ; by shifts and adds
    SHL    BL,1
    SHL    BL,1
    ADD    BL,AL            ; Keep value in BL
    JMP    CommandLoop        ; Get more

Install:
    OR    BL,BL            ; Any value found?
    JNZ    HasDigits        ; Yes, bypass set-to-25
    MOV    BL,25            ; No, set to 25
HasDigits:
    PUSH    CS            ; DS = CS for DOS functs
    POP    DS
    ASSUME    DS:CSEG
    MOV    MaxRows,BL        ; Save for scroll limits
    DEC    MaxRows            ; Adjust line count down
    MOV    LineCount,000H        ; Scroll full page
    MOV    ActPage,000H        ; Assume page 0
    MOV    AX,03509H        ; Get interrupt 9 vector
    INT    021H
    MOV    OldIntr09,BX        ; Save it
    MOV    OldIntr09+2,ES
    MOV    DX,OFFSET NewIntr09    ; Set new interrupt 9 vector
    MOV    AX,02509H
    INT    021H
    MOV    AX,03510H        ; Get interrupt 10 vector
    INT    021H
    MOV    OldIntr10,BX        ; Save it
    MOV    OldIntr10+2,ES
    MOV    DX,OFFSET NewIntr10    ; Set new interrupt 10 vector
    MOV    AX,02510H
    INT    021H
    MOV    DX,OFFSET Message    ; Show installed message
    MOV    AH,009H
    INT    021H
    POP    SI            ; Restore registers
    POP    ES
    POP    DX
    POP    AX
    JMP    SHORT Exit

Delimit    PROC    NEAR
    CMP    AL,9            ; Tab?
    JE    DelimitEnd
    CMP    AL,' '            ; Space?
    JE    DelimitEnd
    CMP    AL,'/'            ; Switch?
    JE    DelimitEnd
    CMP    AL,'-'            ; Unix switch?
    JE    DelimitEnd
    OR    AL,AL            ; Null?
DelimitEnd:
    RET                ; Exit Z or NZ
Delimit    ENDP

Message        DB    'SCROLOCK installed',00DH,00AH,'$'

Exit:
    ASSUME    DS:NOTHING, ES:NOTHING
    LDS    BX,DWORD PTR Packet    ; Restore Packet info
    MOV    WORD PTR [BX+IO_ADDRESS],OFFSET Init    ; Set memory
;    Note: Change "Init" above to correct ending address
    MOV    WORD PTR [BX+IO_ADDRESS+2],CS    ; to be resident
    MOV    [BX+IO_STATUS],00100H    ; Set done bits
    POP    DS            ; Restore registers used
    POP    BX
    RET                ; Exit device installaion
Init    ENDP

;    Delete lines containing "ENDS" and "END" above.

EXEPacket    IOPacket    <>    ; Requires packet space

Start    PROC    NEAR            ; Execute DDD installation
    MOV    SP,OFFSET StackTop    ; Shorten stack
    PUSH    ES            ; Save PSP segment
    MOV    AH,049H            ; Release environment
    MOV    ES,ES:0002CH
    INT    021H
    PUSH    CS            ; DS = CS
    POP    DS
    ASSUME    DS:CSEG
    POP    AX            ; ES:0081 = Command string
    MOV    EXEPacket.IO_COUNT+2,AX    ; Put address in packet
    MOV    EXEPacket.IO_COUNT,00081H
    SUB    AL,AL            ; 0 = Initialize DDD
    MOV    EXEPacket.IO_CMD,AL    ; Put command in packet
    MOV    BX,OFFSET EXEPacket    ; ES:BX = packet address
    PUSH    CS
    POP    ES
    ASSUME    ES:CSEG
    PUSH    CS            ; FAR return
    CALL    StratA            ; Perform strategy
    PUSH    CS            ; FAR return
    CALL    IntrA            ; Perform interrupt
    MOV    DX,EXEPacket.IO_ADDRESS    ; Get ending address
    ADD    DX,0010FH        ; Add PSP and round up
    MOV    CL,4            ; Convert to paragraphs
    SHR    DX,CL
    MOV    AX,03100H        ; DOS stay resident function
    INT    021H

        DW    080H DUP (?)
StackTop    DW    0
Start    ENDP
CSEG    ENDS
    END    Start