C/C++ Users Group Library 1996 July

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Text File | 1991-08-02 | 18.4 KB | 443 lines

PAGE ,132 TITLE SCROLOCK -- Holds screen every page COMMENT $ SCROLOCK.EXE -- 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 as above. To use, toggle the Scroll-Lock key to activate and deactivate. If active, the screen will fill to the bottom, then it will scroll until the line where the cursor was when the last key was struck is now at the top of the screen, then it 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 Alt or either Shift key. $ ; ************************************************************ ; * * ; * Dummy Device Driver Header * ; * * ; ************************************************************ CSEG SEGMENT 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 ; ************************************************************ ; * * ; * Resident data * ; * * ; ************************************************************ ; ROM BIOS DATA AREAS ; ------------------- BIOS_DATA SEGMENT AT 00040H ORG 00017H KB_FLAG DB ? SCROLL_STATE EQU 010H ORG 00050H CURSOR_POSN DW 8 DUP(?) ; 8 pages of cursor positions CURSOR_MODE DW ? ; Current cursor mode setting ACTIVE_PAGE DB ? ; Current page being displayed BIOS_DATA ENDS ; RESIDENT DATA ; ------------- OldIntr09 DW ? ; Interrupt vector storage DW ? OldIntr10 DW ? DW ? LineCount DB ? ; Line counter OddEven DB 0 ; CR sets even = 0 MaxRows DB 25 ; Maximum screen rows ; ************************************************************ ; * * ; * Resident code * ; * * ; ************************************************************ ; Intercept of Interrupt 10H -- BIOS Video Call ; --------------------------------------------- ASSUME CS:CSEG, DS:NOTHING, ES:NOTHING NewIntr10: STI ; Allow interrupts PUSH DS ; Save registers PUSH ES PUSH AX PUSH BX PUSH CX PUSH AX MOV AX,SEG BIOS_DATA ; Set ES = BIOS_DATA segment MOV ES,AX POP AX PUSH CS ; Set DS = CS POP DS ASSUME DS:CSEG, ES:BIOS_DATA TEST KB_FLAG,SCROLL_STATE ; Scroll-Lock on? JZ ExitIntr10 ; No, not locked CMP AH,000H ; Change video mode? JE ClrScr ; Yes, stop at bottom CMP AX,00600H ; Clear video screen? JE ClrScr ; Yes, stop at bottom CMP AX,00601H ; Roll up one line? JE RollUp ; Yes, do that type CMP OddEven,002H ; Is roll active? JE ExitIntr10 ; Yes, don't do cursor CMP AH,002H ; Cursor command? JE CurMov ; Yes, test what move ExitIntr10: POP CX ; Restore registers POP BX POP AX POP ES POP DS ASSUME DS:NOTHING, ES:NOTHING JMP DWORD PTR OldIntr10 ; Perform video request ASSUME DS:CSEG, ES:BIOS_DATA ClrScr: MOV AL,MaxRows MOV LineCount,AL ; Do not allow any roll MOV OddEven,000H ; Reset CR LF counter JMP ExitIntr10 ; Exit Intr svc. RollUp: CMP CX,000H ; From first line? JNE ExitIntr10 ; No, exit MOV AL,MaxRows CMP DH,AL ; To last line? JNE ExitIntr10 ; No, exit INC LineCount ; Yes, now count lines MOV OddEven,002H ; Turn off cursor type RollLoop: CMP LineCount,AL ; Maximum roll? JA RollLoop ; Yes, loop until key pressed JMP ExitIntr10 ; No, roll some more CurMov: CMP BH,ACTIVE_PAGE ; Cursor for active page? JNE ExitIntr10 ; No, set for other page MOV BL,BH ; Get cursor pointer SUB BH,BH SHL BX,1 MOV CX,[BX+CURSOR_POSN] ; Get cursor position CMP CH,MaxRows ; At bottom row? JNE ExitIntr10 ; No, don't do anything OR DL,DL ; To column 0? JNE ExitIntr10 ; No, exit CMP DH,MaxRows ; To last line? JNE ExitIntr10 ; No, exit OR CL,CL ; From column 0? JE NotEven ; Yes, probably a LF MOV OddEven,000H ; A CR for sure - even up NotEven: NOT OddEven ; Alternate CR LF CMP OddEven,000H ; Probable LF? JE ExitIntr10 ; Yes, skip LFs INC LineCount ; No, now count lines CMP LineCount,AL ; Maximum roll? JNA ExitIntr10 ; No, roll some more MOV AH,002H ; Put cursor in corner MOV BH,ACTIVE_PAGE PUSHF CALL DWORD PTR OldIntr10 MOV AL,MaxRows ; Needed for release JMP RollLoop ; Loop as above ; Intrercept of Intrerrupt 9H -- Hardware Keyboard ; ---------------------------------------------- NewIntr09: ASSUME DS:NOTHING, ES:NOTHING PUSH AX ; Save registers IN AL,060H ; Read scan code TEST AL,080H ; Key pressed? JNE ExitIntr09 ; No, exit PUSH BX ; Save registers PUSH CX PUSH DX PUSH ES MOV AX,SEG BIOS_DATA ; Set ES = BIOS_DATA segment MOV ES,AX ASSUME ES:BIOS_DATA MOV BL,ACTIVE_PAGE ; Get cursor pointer SUB BH,BH SHL BX,1 MOV DX,[BX+CURSOR_POSN] ; Get cursor position MOV AH,MaxRows ; Calculate rows to bottom SUB AH,DH MOV LineCount,AH ; Allow roll again POP ES ASSUME ES:NOTHING POP DX ; Restore registers POP CX POP BX ExitIntr09: POP AX JMP DWORD PTR OldIntr09 ; Perform keyboard request ; ************************************************************ ; * * ; * Installation data * ; * * ; ************************************************************ Init PROC FAR Packet DD 0 ; Request packet address ; DEVICE DRIVER REQUEST PACKET ; ---------------------------- 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 Message DB 'SCROLOCK installed',00DH,00AH,'$' ; ************************************************************ ; * * ; * Installation code * ; * * ; ************************************************************ ASSUME DS:NOTHING, ES:NOTHING Strat: MOV WORD PTR Packet,BX ; Save Packet info MOV WORD PTR Packet+2,ES PUSH BX ; Save registers PUSH DS PUSH AX PUSH DX PUSH ES PUSH SI ; NORMAL TSR INSTALLATION ; ----------------------- LDS BX,DWORD PTR Packet ; Get command line location 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 BIOS_DATA ; bit in low MOV DS,AX ; memory 0040:0017 ASSUME DS:BIOS_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 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 ; SPECIAL DDD TERMINATION ; ----------------------- POP SI ; Restore registers POP ES POP DX POP AX ASSUME DS:NOTHING, ES:NOTHING LDS BX,DWORD PTR Packet ; Restore Packet info MOV WORD PTR [BX+IO_ADDRESS],OFFSET Init ; Set memory request 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 Intr: RET ; Exit device installaion Init ENDP 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 CSEG ENDS ; ************************************************************ ; * * ; * Execution data * ; * * ; ************************************************************ EXESEG SEGMENT PARA ; PROGRAM SEGMENT PREFIX ; ---------------------- PSP SEGMENT AT 00000H FilPerProc EQU 20 PSP_Exit_Call DW ? ; INT int_abort system terminate PSP_block_len DW ? ; size of execution block DB ? PSP_CPM_Call DB 5 DUP (?) ; ancient call to system PSP_Exit DD ? ; pointer to exit routine PSP_Ctrl_C DD ? ; pointer to ^C routine PSP_Fatal_abort DD ? ; pointer to fatal error PSP_Parent_PID DW ? ; PID of parent (terminate PID) PSP_JFN_Table DB FilPerProc DUP (?) ; indices into system table PSP_environ DW ? ; seg addr of PSP_environment PSP_User_stack DD ? ; stack of self during system calls PSP_PAD1 DB 1EH DUP (?) PSP_Call_system DB 5 DUP (?) ; portable method of system call PSP_PAD2 DB 6H DUP (?) ; ORG 00080H PSP_CMD_Line DB ? PSP ENDS EXEPacket IOPacket <> ; Requires packet space ToStrat DD StratA ToIntr DD IntrA ; ************************************************************ ; * * ; * Execution code * ; * * ; ************************************************************ ASSUME CS:EXESEG,DS:PSP,ES:NOTHING Start PROC NEAR ; Execute DDD installation PUSH DS ; Save for PSP:0081 MOV AH,049H ; Release environment MOV ES,PSP_environ INT 021H ASSUME DS:CSEG LDS BX,ToStrat ; Get address of StratA MOV AX,[BX] ; to get address of Strat MOV WORD PTR ToStrat,AX ; for FAR CALL LDS BX,ToIntr ; Get address of IntrA MOV AX,[BX] ; to get address of Intr MOV WORD PTR ToIntr,AX ; for FAR CALL PUSH CS POP DS PUSH CS POP ES ASSUME DS:EXESEG,ES:EXESEG POP EXEPacket.IO_COUNT+2 ; Put PSP:0081 address in packet MOV EXEPacket.IO_COUNT,OFFSET PSP_CMD_Line+1 SUB AL,AL ; 0 = Initialize DDD MOV EXEPacket.IO_CMD,AL ; Put command in packet MOV BX,OFFSET EXEPacket ; ES:BX = packet address CALL ToStrat ; Perform strategy CALL ToIntr ; 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 ADD DX,EXEPacket.IO_ADDRESS+2 ; Add highest segment SUB DX,SEG CSEG ; Subtract lowest segment MOV AX,03100H ; DOS stay resident function INT 021H Start ENDP EXESEG ENDS STACK SEGMENT STACK DW 0100H DUP (?) STACK ENDS END Start ; End of File