;DoubleDOS Technical Information 1/06/86 PAGE 60,132 ; This information is to help people who write their own software to ; take advantage of the DoubleDOS dual-tasking environment. ; Applications and System level programs can make direct calls to ; DoubleDOS routines to perform the following functions: ; ; CLEAR THE KEYBOARD BUFFER ; ADD CHARACTERS TO EITHER KEYBOARD BUFFER ; SELECTIVELY ENABLE OR DISABLE ALL KEYBOARD FUNCTIONS ; DETERMINE STATUS OF EITHER MEMORY SECTION ; GIVE UNNEEDED CPU TIME TO THE OTHER MEMORY SECTION ; ENSURE ADEQUATE CPU TIME FOR CRITICAL TIMING APPLICATIONS ; RETURN VIRTUAL SCREEN ADDRESS ; SUSPEND OR RESUME PROCESSING OF THE OTHER MEMORY SECTION ; TERMINATE THE TASK RUNNING IN THE OTHER MEMORY SECTION ; ;The following is a list of function calls that DoubleDOS adds to DOS ;These are additional functions available through INT 21H and appear ;as functions E0 hex to EE hex. (calls F0h - FEh are identical) ;If any of these calls to DOS are made when DoubleDOS is NOT running, ;then no function is performed and AL is returned zero by DOS. ; Note: ; If your program must run with non PC-DOS Operating Systems ; then calls E0-EE must be used and not F0-FE. Both ranges ; are functionally identical. ; ;FUNCTION -------------------DESCRIPTION---------------------- ; ; E0 DoubleDOS MENU CONTROL FUNCTIONS ; AL = 1 EXCHANGE VISIBLE & INVISIBLE TASK STATUS ; AL = 73H RESUME INVISIBLE JOB IF SUSPENDED ; AL = 74H KILL OTHER JOB ; AL = 75H SUSPEND INVISIBLE JOB ; ; E1 CLEAR KEYBOARD BUFFER ; THIS CALL WILL RESET THE KEYBOARD BUFFER TO EMPTY FOR ; THE CALLING PROGRAM ONLY. THIS CALL DOES NOT CLEAR ; THE STANDARD INPUT BUFFER IF IT IS NOT THE KEYBOARD. ; ; E2 SEND ASCII CHARACTER IN AL TO OTHER KEYBOARD BUFFER ; THIS CALL ALLOWS A PROGRAM TO GIVE KEYBOARD INPUT TO ; ANOTHER PROGRAM, OR TO START ANOTHER PROGRAM IN THE ; OTHER MEMORY SECTION. AL RETURNS ZERO IF TRANSFER IS ; SUCCESSFUL, 1 IF BUFFER IS FULL. KEYBOARD BUFFERS WILL ; HOLD 128 CHARACTERS MAX ; NOTE: ; IF AL=0FFH THEN THE CHARACTER IN DL AND SCAN CODE ; IN DH ARE SENT TO THE OTHER TASK ; ; E3 ADD ASCII CHARACTER IN AL TO KEYBOARD BUFFER ; THIS CALL ALLOWS A PROGRAM TO ADD CHARACTERS TO ITS ; OWN KEYBOARD BUFFER. ERROR RETURN IS SAME AS FOR E2 ; THIS ALLOWS A PROGRAM TO RECIEVE ITS KEYBOARD INPUT ; FROM BOTH THE KEYBOARD AND ANY OTHER SOURCE(S). ; PROGRAMMABLE REDIRECTION OF KEYBOARD INPUT CAN ; BE ACCOMPLISHED BY USING THIS CALL IN CONJUNCTION ; WITH FUNCTION E8 TO DISABLE THE KEYBOARD (THIS ; WILL PREVENT UNEXPECTED USER INTERVENTION), AND ; OPTIONALLY FUNCTION E1 TO FLUSH UNWANTED KEYBOARD ; INPUT. WHEN REDIRECTION IS COMPLETED, THE KEYBOARD ; CAN BE REENABLED WITH FUNCTION E8 ; NOTE: ; IF AL=0FFH THEN THE CHARACTER IN DL AND SCAN CODE ; IN DH ARE ADDED TO THE KEYBOARD BUFFER ; ; E4 RETURN CURRENT PROGRAM STATUS IN AL: ; AL = 1 PROGRAM IS VISIBLE ; AL = 2 PROGRAM IS INVISIBLE ; AL = ANY OTHER VALUE MEANS DoubleDOS NOT RUNNING ; AH = TASK NUMBER (0=TOP; 1=BOTTOM JOB) ; ; E5 RETURN OTHER PROGRAM STATUS IN AL: ; AL = 0 NO PROGRAM RUNNING ; AL = 1 PROGRAM IS RUNNING ; AL = 2 PROGRAM IS SUSPENDED ; ; E8 SET KEYBOARD CONTROL FLAGS ; KEYBOARD CONTROL FLAGS CAN BE RESET BY BITS IN DX ; AL = 0 TO SET FLAGS FOR THIS PROGRAM ; AL = 1 TO SET FLAGS FOR OTHER PROGRAM ; ;NOTE: AL = 2 , 3 AND 4 ARE USED BY OUR CAROUSEL PRODUCT ; ; AL = 2 SET SPECIAL FUNCTION MODE ; INPUT: DS:SI POINTS TO 8 CHARACTER NAME OF FUNCTION ; AL = 3 READ SPECIAL FUNCTION MODE ; OUTPUT: AL=0 IF NO SPECIAL FUNCTION IS ACTIVE ; AL=1 IF SPECIAL MODE IS SET ; ES:DI WILL RETURN POINTING TO NAME OF FUNCTION ; AL=4 CANCEL SPECIAL FUNCTION MODE ; ; DX = KEYBOARD CONTROL FLAGS: ; 0001 BIT 0 = MENU ; 0002 BIT 1 = EXCHANGE ; 0004 BIT 2 = ALT/CAPSLOCK (SUSPEND KEY) ; 0008 BIT 3 = CTRL/C ; 0010 BIT 4 = CTRL/PRTSC ; 0020 BIT 5 = ALT/ERASE ; 0040 BIT 6 = CTRL/BREAK ; 0080 BIT 7 = CTRL/NUMLOCK ; 0100 BIT 8 = SHIFT/PRTSC ; 0200 BIT 9 = CANCEL KEY (CLEAR KEYBOARD BUFFER) ; 0400 BIT 10 = (UNDEFINED) ; 0800 BIT 11 = (UNDEFINED) ; 1000 BIT 12 = (UNDEFINED) ; 2000 BIT 13 = (UNDEFINED) ; 4000 BIT 14 = (UNDEFINED) ; 8000 BIT 15 = ENTIRE KEYBOARD ENABLE/DISABLE ; ; NOTES: DISABLING CTRL/PRTSC (BIT 4 = 0) WILL ALLOW THIS ; KEY SEQUENCE TO BE INTERCEPTED BY APPLICATIONS PROGRAMS. ; DISABLING ANY OTHER KEY SEQUENCE DISABLES THOSE KEYS ; COMPLETELY. ; ; IN ALL CASES A "1" MEANS ENABLE AND A "0" DISABLE ; BITS 0 & 1 = 0 DISABLE THE KEYBOARD FUNCTIONS ONLY. ; THEY DO NOT DISABLE FUNCTION F0. ; ; ON RETURN DX CONTAINS PREVIOUS FLAGS ; ; E9 SET TIMESHARING PRIORITY ; AL = 0 VISIBLE PROGRAM GETS 70% INVISIBLE GETS 30% (DEFAULT) ; AL = 1 VISIBLE PROGRAM GETS 50% INVISIBLE GETS 50% OF TIME ; AL = 2 VISIBLE PROGRAM GETS 30% INVISIBLE GETS 70% OF TIME ; AL = 3 TOP PROGRAM GETS 70% BOTTOM PROGRAM GETS 30% OF TIME ; AL = 4 TOP PROGRAM GETS 30% BOTTOM PROGRAM GETS 70% OF TIME ; AL = 5 RETURNS CURRENT PRIORITY SETTING IN AL ; ; EA THIS CALL PERFORMS INT 0FAH DESCRIBED BELOW ; ; EB THIS CALL PERFORMS INT 0FBH DESCRIBED BELOW ; ; EC THIS CALL PERFORMS INT 0FCH DESCRIBED BELOW ; ; ED RESERVED FOR DoubleDOS ; ; EE THIS CALL PERFORMS INT 0FEH DESCRIBED BELOW ; ; In addition to these DOS function calls, DoubleDOS also reserves ;and defines certain interrupt vectors. ;THE FOLLOWING INTERRUPTS ARE PROVIDED TIME-SHARING: ;0-7,9,10,13-2E,60-67,80-F3,FF ;Each memory section can have a unique address for these ;THE FOLLOWING INTERRUPTS ARE NOT PROVIDED TIME-SHARING: ;8,A-F,11,12,2F-57,68-7F ;Only one memory section at a time can use these ;THE FOLLOWING INTERRUPTS ARE USED BY DoubleDOS AND CANNOT BE REPLACED: ;(NO MATTER HOW HARD YOU TRY) ;58-5F,F4-FE ;Some of the DoubleDOS reserved interrupts may be used directly by programs ;running under DoubleDOS. Although DoubleDOS provides access to these ;routines through the DOS INT 21H, Critical timing applications may ;incorporate these interrupts directly by one of the following methods: ; ; 1. Do not perform these interrupts if DoubleDOS is not resident ; or ; 2. Install a default routine for each of the vectors to be used ; (If DoubleDOS is resident, you can not actually change the ; contents of vectors F2-FE. Therefore the DoubleDOS routines ; and not the default routines would be called.) ; ;Here is the list of interrupts that DoubleDOS installs: ; INT 58-5F USED TO INTERCEPT IRQ0-IRQ7 FROM THE MASTER 8259 ; DO NOT ISSUE THESE INTERRUPTS DIRECTLY ; INT F4 SWITCH TO OTHER TASK FOR REMAINDER OF CURRENT ; CLOCK CYCLE PLUS ONE CLOCK CYCLE ; INT F5 USED BY DoubleDOS ; INT F6 RESERVED FOR FUTURE USE BY DoubleDOS ; INT F7-F9 USED BY DoubleDOS ; DO NOT ISSUE THESE INTERRUPTS DIRECTLY ; INT FA TURN OFF TIMESHARING, CTRL/BREAK, CTRL/NUMLOCK & MENU ; (ALSO PERFORMED BY FUNCTION CALLS EA & FA) ;INPUT: NONE. ;OUTPUT: AFTER THIS INTERRUPT IS ISSUED, THE CALLING PROGRAM ; WILL HAVE FULL-TIME USE OF ALL SYSTEM RESOURCES UNTIL ; AN INT 0FBH IS ISSUED. THIS CALL CAN BE USED FOR ; TIMING SENSITIVE AND NON-INTERRUPTIBLE ROUTINES, ; SUCH AS COMMUNICATIONS OR DEVICE CONTROLLERS. ; THE OTHER MEMORY SECTION IS SUSPENDED BY THIS CALL. ; DoubleDOS MENU FUNCTIONS, CTRL/BREAK AND CTRL/NUMLOCK ; ARE DISABLED BY THIS CALL. A REQUEST FOR ANY OF THESE ; WILL BE SAVED AND PROCESSED AFTER INT 0FBH IS ISSUED. ; ANY DOS FUNCTION LESS THAN 0DH WILL AUTOMATICALLY ; TERMINATE THIS MODE AS IF INT 0FBH HAD BEEN ISSUED ; INT FB TURN ON TIMESHARING, ETC. ; (ALSO PERFORMED BY FUNCTION CALL EB & FB) ;INPUT: NONE. ;OUTPUT: THIS CALL HAS NO FUNCTION UNLESS AN INT FA HAS OCCURED, THEN ; NORMAL DoubleDOS TIMESHARING FUNCTIONS ARE RESTORED, THE ; OTHER MEMORY SECTION IS NO LONGER SUSPENDED, THE DoubleDOS ; MENU, CTRL/BREAK, CTRL/NUMLOCK WILL BE OPERATIONAL. ; IF MORE THAN ONE INT FA WAS ISSUED, ALL WILL BE CANCELED ; BY ONE INT FB ; INT FC RETURN CURRENT DISPLAY BUFFER ADDRESS IN ES ; (ALSO PERFORMED BY FUNCTION CALL EC & FC) ;INPUT: NONE. ;OUTPUT: THE SEGMENT ADDRESS OF THE CURRENT DISPLAY BUFFER IS RETURNED ; IN THE ES REGISTER. THIS FUNCTION IS USED FOR PROGRAMS ; WHICH DO DIRECT SCREEN UPDATES, SUCH AS 1-2-3. ; THE ADDRESSES RETURNED WILL BE: ; B800H IF PROGRAM IS VISIBLE ON COLOR ADAPTER ; B000H IF PROGRAM IS VISIBLE ON MONOCHROME ADAPTER ; XXXXH IF PROGRAM IS INVISIBLE (ADDRESS OF VIRTUAL BUFFER) ; ; INT FD USED BY DoubleDOS ; DO NOT ISSUE THIS INTERRUPT DIRECTLY ; ; INT FE GIVE TIME TO OTHER TASK ; (ALSO PERFORMED BY FUNCTION CALL FE) ;INPUT: AL = 0-0FFH NUMBER OF 55ms TIME INTERVALS TO GIVE AWAY ; ;OUTPUT: ON THE NEXT TIMER INTERRUPT FOLLOWING THIS CALL, ; IF THE OTHER MEMORY SECTION IS ACTIVE, IT WILL RECEIVE ; AL EXTRA 55ms TIME INTERVALS BEFORE THE CALLING PROGRAM ; WILL RECEIVE ANOTHER INTERVAL. A LOOP OF THESE CALLS ; WILL ALLOW THE CALLING PROGRAM TO GIVE ALL OF ITS ; WASTED TIME TO THE OTHER MEMORY SECTION. PROGRAMS ; WAITING FOR KEYBOARD INPUT COULD DO THE FOLLOWING: ; ; KEYLOOP: MOV AH,1 ; INT 16H ;GET KEYBOARD STATUS ; JNZ HAVE_ONE ;A KEY WAS STUCK ; CALL DO_ANYTHING ;REST OF PROCESS LOOP ; ; **** HERES A GOOD PLACE TO GIVE SOME TIME TO THE OTHER TASK ; ; MOV AL,2 ;GIVE EXTRA 110ms TO OTHER TASK ; INT 0FEH ;OTHER TASK ALSO GETS UNUSED PORTION ; ;OF CURRENT CLOCK CYCLE ; JMP KEYLOOP ;OTHER TASK HAS ALREADY RUN ; ;NOTE: THIS INTERRUPT WILL NOT GUARANTEE THAT THE REQUESTED TIME ; WILL ACTUALLY BE SPENT BY THE OTHER PROGRAM. IF THE OTHER ; PROGRAM IS ALSO "GIVING AWAY TIME" DOING KEYBOARD INPUT, PRINTING ; ETC. THEN YOUR ROUTINE WILL STILL RECEIVE ALL UNUSED PROCESSING ; TIME, ie WHEN THE OTHER TASK DOES INT 0FEH IT WILL FORCE AN ; IMMEDIATE RETURN FROM THE INT 0FEH IN YOUR PROGRAM. ; DoubleDOS USES THIS ROUTINE TO FACILITATE OVERLAPPED ; PROCESSING WHEN WAITING FOR DEVICES TO RESPOND ;DoubleDOS VIDEO ROUTINES (INT 10H): ; The BIOS replacement video handler built into DoubleDOS is ; enhanced to provide all features of the IBM PC-AT video handler ; including the WRITE STRING function, as well as all INT 10H video ; features built into the IBM TOPVIEW product. these features are ; syntactically identical to their IBM counterparts. ;This is the source code for the "SWITCH.EXE" program supplied on your ;DoubleDOS disk. This program can be included in batch files to perform ;some of the DoubleDOS menu functions. It is included as an example of ;how to use the DoubleDOS extended function set. ;PROGRAM OPTIONS: ; ;SWITCH/I WILL MAKE THIS MEMORY SECTION INVISIBLE ;SWITCH/V WILL MAKE THIS MEMORY SECTION VISIBLE ;SWITCH WILL EXCHANGE THE VISIBLE/INVISIBLE SECTIONS ; ;NOTE: THE TERM "VISIBLE" MEANS "HAS KEYBOARD ATTACHED" ; THE TERM "INVISIBLE" MEANS "NO KEYBOARD ATTACHED" NAME SWITCH CODE SEGMENT ASSUME CS:CODE,DS:CODE,SS:STACK ORG 100H START: PUSH ES POP DS ;LOOK FOR OPTIONS MOV SI,80H ;AT PSP+80H CLD LODSB ;GET THE COUNT BYTE CBW MOV CX,AX ;NUMBER OF CHARACTERS TO TEST JCXZ EXCHANGE ;NO OPTION IS UNCONDITIONAL EXCHANGE LOOKOPT:LODSB ;GET NEXT OPTION BYTE CMP AL,60H ;CONVERT ALL ALPHA CHARS TO UPPER CASE JB UPPER_CASE ;FOR TEST SUB AL,20H UPPER_CASE: CMP AL,'I' ;TEST FOR "MAKE INVISIBLE" JE MAKE_INVISIBLE CMP AL,'V' ;TEST FOR "MAKE VISIBLE" JE MAKE_VISIBLE CMP AL,'F' ;TEST FOR CTRL/PRTSC "OFF" JE PRTSC_OFF CMP AL,'N' ;TEST FOR CTRL/PRTSC "ON" JE PRTSC_ON LOOP LOOKOPT ;LOOK AT ALL CHARACTERS ENTERED EXCHANGE: ;EXCHANGE VISIBLE AND INVISIBLE SECTIONS MOV AX,0E001H INT 21H ;CALL DoubleDOS KEYBOARD EXCHANGE ALL_DONE: MOV AH,4CH ;TERMINATE INT 21H JMP $ MAKE_VISIBLE: MOV AH,0E4H ;GET KEYBOARD STATUS INT 21H ;FROM DoubleDOS CMP AL,1 ;ARE WE VISIBLE ? JNZ EXCHANGE ;NO - EXCHANGE KEYBOARD JMP ALL_DONE ;YES - NO ACTION REQUIRED MAKE_INVISIBLE: MOV AH,0E4H ;GET KEYBOARD STATUS INT 21H ;FROM DoubleDOS CMP AL,2 ;ARE WE INVISIBLE ? JNZ EXCHANGE ;NO - EXCHANGE KEYBOARD JMP ALL_DONE ;YES - NO ACTION REQUIRED PRTSC_OFF: MOV AX,0E800H ;SET KEYBOARD FLAGS FOR THIS JOB MOV DX,0 ;SET ALL KEYBOARD FLAGS OFF INT 21H ;FIRST CALL WILL RETURN FLAGS IN DX AND DX,0FFEFH ;TURN OFF BIT FOR CTRL/PRTSC INT 21H ;RESET KEYBOARD FLAGS JMP ALL_DONE PRTSC_ON: MOV AX,0E800H ;SET KEYBOARD FLAGS FOR THIS JOB MOV DX,0 ;SET ALL KEYBOARD FLAGS OFF INT 21H ;FIRST CALL WILL RETURN FLAGS IN DX OR DL,10H ;ENABLE CTRL/PRTSC BIT INT 21H ;RESET KEYBOARD FLAGS JMP ALL_DONE CODE ENDS STACK SEGMENT STACK DB 100H DUP(0) STACK ENDS END START ;IF YOU ARE HAVING PROBLEMS, OR WOULD LIKE FURTHER ASSISTANCE: ;CALL 603-644-5555 9:00 - 17:00 est. ask for DoubleDOS technical support ; or write ; SoftLogic Solutions Incorporated ; 530 Chestnut street ; Manchester, NH 03101