Programmer 7500/MAX_PROGRAMMERS.iso/INFO/ASMUTL/ASM002.ZIP/SCRN.ASM

Assembly Source File | 1985-05-11 | 11.8 KB | 338 lines

    TITLE    SCRN - SCREEN SAVE RESIDENT UTILITY COMMAND, Version 2.2
    PAGE    60,132                  ; JAN 21, 1984
COMMENT |
╔═══════════════════════════════════════════════════════════════════╗
║           Copyright (c), 1984 by J. T. Thannum            ║
║           All rights reserved.  May be copied            ║
║           for personal non-commercial use only.            ║
╚═══════════════════════════════════════════════════════════════════╝

SCRN n
  [options]
    n - The Delay Interval in Minutes as a single Integer from 1 to 9
        [Default: 10 Minutes]

SCRN is a screen saver utility command which operates using the Timer,
Video and Keyboard Interrupts to monitor activity of the system user.  Upon
detecting no entry via the keyboard OR output to the monitor(s) for "n" min.
the SCRN routine will turn off the video to all monitors attached to the
system.  The idea for this program originated from an article in Softalk,
Dec.  1983 by John Socha.  However, the version presented in this article
had several limitations which needed to be corrected for a viable
permanmently resident utility.    These limitations became the design
criteria for this version, as follows:

    1. Must turn "both" color and monochrome monitors off, not
       just the active monitor on two monitor systems.
    2. Must function in a single monitor envirnoment with either
       monitor attached.
    3. Must be extremely frugal in execution.  Since this routine
       will be executed at each timer interrupt,or 18.2 times/sec,
       and at each keyboard interrupt the routine must have the
       minimum of overhead so as not to degrade system performance.
    4. Must be able blank background on color monitor as well as
       foreground text or graphics.
    5. Should utilize the User Exit Interrupt provided in the
       Timer Routine. [INT 1C] (This can be considered optional)
    6. Handle the blanking of the cursor on the Monochrome display
       more efficiently.
    7. Output to the Monitor(s) should reset the timeout counter
       within the delay window but not turn the video back on if
       a timeout has occurred.
    8. Optional Parameter to set Delay Interval from 1 to 10 min.

(Special Note:    The Mode register definition shown in the Softalk article
        is incorrect as well as the referenced Enable Video bit.
        The program is correct as shown in the article.)

For efficiency and execution the Screen Saver program "hard codes"
addresses and uses its own routine to set adapter parameters.  However,
this hard coding is done via equates and because of the brevity of the
program this would cause only  minor problems if changes were required.

                        J. T. Thannum
                        Naperville, Ill 60540
|
        PAGE
;
; System Interrupt Vectors for BIOS and DOS
;    - TIMER_INT Routine User Exit [INT 1C] redirected by SCRN
;    - KB_INT Routine [INT 9] intercepted by SCRN
;    - VIDEO_INT Routine [INT 10] intercepted by SCRN
;
INT_VECTORS    SEGMENT AT 0
        ORG    9H*4
KB_INT        LABEL    DWORD        ;KEYBOARD INTERRUPT
        ORG    10H*4
VIDEO_INT    LABEL    DWORD        ;VIDEO I/O INTERRUPT
        ORG    1CH*4
TIMER_EXIT    LABEL    DWORD        ;TIMER USER ROUTINE EXIT

INT_VECTORS    ENDS
;
; ROM BIOS Data Area
;
DATA        SEGMENT AT 40H
        ORG    10H
EQUIP_FLAG    DW    ?        ;EQUIPMENT INSTALLED IN SYSTEM
        ORG    60H
CURSOR_MODE    DW    ?        ;CURRENT CURSOR MODE FOR ACTIVE DISPLAY
        ORG    63H
ADDR_6845    DW    ?        ;BASE ADDRESS OF ACTIVE ADAPTER
CRT_MODE_SET    DB    ?        ;CURRENT SETTING OF 3x8 REGISTER
CRT_PALLETTE    DB    ?        ;CURRENT COLOR SETTINGS

DATA        ENDS
        PAGE
;
; SCRN - Screen Save Program Code Segment
;    -Main Procedures:
;        -TIMER_USER_ROUTINE - Processing at each Timer Interrupt to
;                      determine if video should be turned "off"
;        -KEYBOARD_INTERCEPT - Processing at each Keyboard interrupt to
;                      determine of video should be turned "on".
;                      Resets delay counter at each invocation.
;        -VIDEO_IO_INTERCEPT - Processing at each Video I/O interrupt to
;                      keep video on by resetting delay counter.
;        -INIT_PROC        - Initialize program and make resident. Not
;                      retained in memory with resident portion
;        -CURSOR_SET        - Subroutine to turn Monochrome Adapter
;                      cursor on and off
;
SCREEN_SAV    SEGMENT PUBLIC 'CODE'
        ASSUME    CS:SCREEN_SAV
;
; Program Segment Prefix
;    - Location of Command Parameters
;    - For Valid Parameter String the PARM_COUNT = 2 and the
;      PARM_DATA byte will be 1 to 9 (31H to 39H ASCII)
;
        ORG    80H
PARM_COUNT    DB    ?        ;NO. OF CHARACTERS IN PARAMETER STRING
SPACE        DB    ?
PARM_DATA    DB    ?        ;DELAY VALUE PARAMETER
;
        ORG    100H
BEGIN:        JMP    INIT_PROC        ;INITIALIZE & MAKE RESIDENT
;
; Program Save Area for Interrupts and Data
;
BIOS_KB_INT    DD    ?        ;BIOS INTERRUPT POINTERS FOR KEYBOARD
BIOS_VIDEO_INT    DD    ?        ;BIOS INTERRUPT POINTERS FOR VIDEO I/O
BIOS_TIMER_EXIT DD    ?        ;BIOS INTERRUPT POINTERS FOR TIMER EXIT
VIDEO_STATUS    DB    8        ;SET BIT 4 TO ONE - INITIALIZES AS "ON"
DELAY_VALUE    DW    2AA8H        ;SETS DELAY INTERVAL - DEFAULT 10 MIN
DELAY_COUNTER    DW    2AA8H        ;COUNTDOWN TIMER - INIT @ DEFAULT
MESSAGE     DB    'Screen Saver, Ver. 2.2',CR,LF,'$'
;
; Equates
;
CR        EQU    0DH        ;CARRIAGE RETURN
LF        EQU    0AH        ;LINE FEED
VALID_COUNT    EQU    2        ;VALID COMMAND PARAMETER STRING COUNT
DELAY_1_MIN    EQU    444H        ;DELAY INTERVAL FOR 1 MINUTE
VIDEO_OFF    EQU    8        ;TEST VALUE FOR VIDEO OFF BIT
MONO_CUR_OFF    EQU    2B0CH        ;VALUES TO WRITE TO CURSOR REGISTERS
MONO_CUR_ON    EQU    0B0CH        ;    TO TURN CURSOR "ON" AND "OFF"
COLOR_MODE_REG    EQU    3D8H        ;ADDRESSES FOR EACH ADAPTERS
MONO_MODE_REG    EQU    3B8H        ;    6845 MODE REGISTER
ADDR_6845_MONO    EQU    3B4H        ;MONOCHROME ADAP.- 6845 ADDRESS REGISTER
COLOR_SEL_REG    EQU    3D9H        ;COLOR ADAP.- 6845 COLOR SELECT REGISTER
REG_10        EQU    10        ;CURSOR START REGISTER - CURSOR ENABLE
REG_11        EQU    11        ;CURSOR END   REGISTER
DEF_MODE_ON    EQU    29H        ;DEFAULT CRT_MODE_SET FOR VIDEO ENABLED
DEF_MODE_OFF    EQU    21H        ;   "     "    "   "   "    "  DISABLED
COLOR_ACTIVE    EQU    10H        ;TEST FOR ACTIVE MONITOR ADAPTER
BG_BLACK    EQU    0FH        ;TEST FOR BLACK BACKGROUND SETTING
        PAGE
;
; Timer Exit Routine - Determines if video should be turned off
;    -Uses INT 1C, but chains interrupt in the event additional user routines
;     are installed
;
TIMER_USER_ROUTINE  PROC NEAR
        ASSUME CS:SCREEN_SAV,DS:DATA
        PUSH    AX
        PUSH    DS
        MOV    AX,DATA         ;ESTABLISH DATA SEGMENT
        MOV    DS,AX
        TEST    VIDEO_STATUS,VIDEO_OFF    ;IS VIDEO, OFF?
        JZ    EXIT_TIMER        ;  YES, NO ACTION IS REQUIRED
        DEC    DELAY_COUNTER        ;HAS DELAY TIME ELAPSED?
        JNZ    EXIT_TIMER        ;  NO, THEN NO ACTION IS REQ'D
;
        CLI
        PUSH    DX
        PUSH    CX
;
; Turn Monochrome Video OFF including Cursor
;
        MOV    DX,MONO_MODE_REG ;SET OUTPUT TO MODE REGISTER,
        MOV    AL,DEF_MODE_OFF  ;  GET DATA TO OUTPUT
        OUT    DX,AL         ;  THEN TURN OFF WITH DEFAULT MODE
        MOV    CX,MONO_CUR_OFF  ;SET TO TURN CURSOR OFF,
        CALL    CURSOR_SET     ;  THEN CALL ROUTINE TO DO IT
;
; Turn Color Video OFF
;
        TEST    EQUIP_FLAG,COLOR_ACTIVE ;IS COLOR DISPLAY ACTIVE?
        JZ    GET_MODE        ;  YES, THEN GET CURRENT MODE
        MOV    AL,DEF_MODE_OFF     ;  NO,    THEN USE DEFAULT MODE
        JMP    SHORT CONT
GET_MODE:    MOV    AL,CRT_MODE_SET     ;CURRENT ACTIVE MODE SETTING
        AND    AL,0F7H         ;TURN VIDEO ENABLE BIT OFF
        MOV    CRT_MODE_SET,AL     ;SAVE NEW MODE SETTING
CONT:        MOV    DX,COLOR_MODE_REG    ;GET ADDRESS OF MODE REGISTER
        OUT    DX,AL            ; THEN OUTPUT TO TURN VIDEO OFF
        TEST    CRT_PALLETTE,BG_BLACK    ;IS BACKGROUND COLOR BLACK?
        JZ    DONE            ;  YES, THEN DONE
        MOV    AL,CRT_PALLETTE     ;  ELSE, GET CURRENT PALLETTE
        AND    AL,0F0H         ;SET FOR BLACK BACKGROUND
        MOV    DX,COLOR_SEL_REG    ;GET ADDR OF COLOR SELECT REG
        OUT    DX,AL            ;SET BACKGROUND TO BLACK
DONE:        AND    VIDEO_STATUS,0F7H    ;SET VIDEO STATUS "OFF"
        POP    CX
        POP    DX
        STI
EXIT_TIMER:    POP    DS
        POP    AX
        JMP    BIOS_TIMER_EXIT     ;CHAIN TO NEXT ROUTINE OR EXIT
                        ; TO FINISH TIMER INTERRUPT
TIMER_USER_ROUTINE    ENDP
        PAGE
;
; Keyboard Intercept Routine
;    -Intercepts Keyboard INT 9, checks if video should be turned on
;     then chains to normal keyboard processing
;
KEYBOARD_INTERCEPT PROC NEAR
        ASSUME CS:SCREEN_SAV,DS:DATA
        PUSH    AX
        PUSH    DS
        MOV    AX,DATA         ;ESTABLISH DATA SEGMENT
        MOV    DS,AX
        MOV    AX,DELAY_VALUE        ;RESET,
        MOV    DELAY_COUNTER,AX    ;  DELAY COUNTER
        TEST    VIDEO_STATUS,VIDEO_OFF    ;IF VIDEO IS ON,
        JNZ    EXIT_KB         ;  EXIT, NO ACTION IS REQUIRED
;
        CLI
        PUSH    DX
        PUSH    CX
;
; Turn Monochrome Video ON including Cursor
;
        MOV    DX,MONO_MODE_REG ;SET OUTPUT TO MODE REGISTER,
        MOV    AL,DEF_MODE_ON     ;  GET DATA TO OUTPUT,
        OUT    DX,AL         ;  THEN TURN OFF WITH DEFAULT MODE
        MOV    CX,MONO_CUR_ON     ;SET TO TURN CURSOR ON,
        CALL    CURSOR_SET     ;  THEN CALL ROUTINE TO DO IT
;
; Turn Color Video ON
;
        TEST    EQUIP_FLAG,COLOR_ACTIVE ;IS COLOR DISPLAY ACTIVE?
        JZ    GET_MODE1        ;  YES, THEN GET CURRENT MODE
        MOV    AL,DEF_MODE_ON        ;  NO,    THEN USE DEFAULT MODE
        JMP    SHORT CONT1
GET_MODE1:    MOV    AL,CRT_MODE_SET     ;CURRENT ACTIVE MODE SETTING
        OR    AL,8            ;TURN VIDEO ENABLE BIT ON
        MOV    CRT_MODE_SET,AL     ;SAVE NEW MODE SETTING
CONT1:        MOV    DX,COLOR_MODE_REG    ;GET ADDRESS OF MODE REGISTER
        OUT    DX,AL            ; THEN OUTPUT TO TURN VIDEO ON
        TEST    CRT_PALLETTE,BG_BLACK    ;IS BACKGROUND COLOR BLACK?
        JZ    DONE1            ;  YES, THEN DONE
        MOV    AL,CRT_PALLETTE     ;  ELSE, GET CURRENT PALLETTE
        MOV    DX,COLOR_SEL_REG    ;GET ADDR OF COLOR SELECT REG
        OUT    DX,AL            ;RESTORE BACKGROUND COLOR
DONE1:        OR    VIDEO_STATUS,8        ;SET VIDEO STATUS "ON"
        POP    CX
        POP    DX
        STI
EXIT_KB:    POP    DS
        POP    AX
        JMP    BIOS_KB_INT        ;CHAIN TO NEXT ROUTINE OR EXIT
                        ; TO FINISH TIMER INTERRUPT
KEYBOARD_INTERCEPT    ENDP
        PAGE
;
; Video I/O Intercept Routine
;    -Intercepts Video I/O INT 10H, resets the delay counter
;     then chains to normal Video I/O processing
;
VIDEO_IO_INTERCEPT PROC NEAR
        ASSUME CS:SCREEN_SAV,DS:NOTHING
        PUSH    AX
        MOV    AX,DELAY_VALUE        ;RESET,
        MOV    DELAY_COUNTER,AX    ;  DELAY COUNTER
        POP    AX
        JMP    BIOS_VIDEO_INT        ;CHAIN TO VIDEO I/O INTERRUPT
                        ; PROCESSING
VIDEO_IO_INTERCEPT    ENDP
;
; Subroutine to Turn Monochrome Adapter Cursor ON or OFF
;
CURSOR_SET    PROC    NEAR
        ASSUME    CS:SCREEN_SAV,DS:DATA
        MOV    DX,ADDR_6845_MONO    ;SET TO WRITE ADDRESS REGISTER,
        MOV    AL,REG_10        ;  SELECT CURSOR START REGISTER
        OUT    DX,AL            ;  OUTPUT REGISTER SELECTION
        INC    DX            ;POINT TO 6845 DATA REGISTER
        MOV    AL,CH            ;GET CURSOR START VALUE, THEN
        OUT    DX,AL            ;  SET START REGISTER
        DEC    DX            ;POINT BACK TO ADDRESS REGISTER
        MOV    AL,REG_11        ;  SELECT CURSOR END REGISTER
        OUT    DX,AL            ;  OUTPUT REGISTER SELECTION
        INC    DX            ;POINT AGAIN TO DATA REGISTER
        MOV    AL,CL            ;GET CURSOR END VALUE, THEN
        OUT    DX,AL            ;  SET END REGISTER
        RET
CURSOR_SET    ENDP
        PAGE
;
; Initialize Screen Save Program and Make Resident
;
INIT_PROC    PROC    NEAR
        ASSUME    DS:INT_VECTORS
        MOV    AX,INT_VECTORS
        MOV    DS,AX
        PUSH    ES
        CLI
        LES    AX,KB_INT        ;SAVE KB_INT
        MOV    BIOS_KB_INT,AX        ;  POINTERS TO
        MOV    BIOS_KB_INT[2],ES    ;      BIOS KEYBOARD ROUTINE
        MOV    KB_INT,OFFSET KEYBOARD_INTERCEPT  ;SET KEYBOARD INT
        MOV    KB_INT[2],CS              ;  TO POINT HERE
;
        LES    AX,VIDEO_INT        ;SAVE VIDEO_INT
        MOV    BIOS_VIDEO_INT,AX    ;  POINTERS TO
        MOV    BIOS_VIDEO_INT[2],ES    ;      BIOS VIDEO I/O ROUTINE
        MOV    VIDEO_INT,OFFSET VIDEO_IO_INTERCEPT  ;SET VIDEO I/O INT
        MOV    VIDEO_INT[2],CS              ;    TO POINT HERE
;
        LES    AX,TIMER_EXIT        ;SAVE ANY OTHER USER
        MOV    BIOS_TIMER_EXIT,AX    ;  ROUTINE USING
        MOV    BIOS_TIMER_EXIT[2],ES    ;      TIMER EXIT
        MOV    TIMER_EXIT,OFFSET TIMER_USER_ROUTINE ;SET TIMER EXIT
        MOV    TIMER_EXIT[2],CS             ;    TO POINT HERE
;
        CMP    PARM_COUNT,VALID_COUNT    ;CHECK FOR OPTIONS
        JNZ    DEFAULT         ;  NONE, USE DEFAULT OF 10 MIN
        MOV    AL,PARM_DATA        ;GET DELAY OPTION AND
        AND    AX,000FH        ;  CONVERT ASCII TO BINARY
        MOV    BX,DELAY_1_MIN        ;LOAD DELAY VALUE FOR 1 MIN
        MUL    BX            ;CALCULATE DELAY VALUE
        MOV    DELAY_VALUE,AX        ;SAVE DELAY VALUE
        MOV    DELAY_COUNTER,AX    ;SET DELAY COUNTER
DEFAULT:    STI
        ASSUME    DS:SCREEN_SAV
        MOV    AX,CS
        MOV    DS,AX
        MOV    DX,OFFSET MESSAGE    ;PRINT INTRO
        MOV    AH,9
        INT    21H
        MOV    DX,OFFSET INIT_PROC    ;END OF RESIDENT PORTION
        INT    27H            ;  TERMINATE AND STAY RESIDENT
INIT_PROC    ENDP
SCREEN_SAV    ENDS
        END    BEGIN