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Assembly Source File | 1993-05-01 | 52.6 KB | 889 lines

PAGE 60,132 TITLE 4DOS24H2.ASM SUBTTL Critical Error Handler for 4DOS ; ; Copenhagen, August 3. 1992 (revised May 1992) ; ; The documentation, this source file and the compiled program are released ; to the Public Domain. Nobody is authorized to charge any amount of money ; for the included files. Feel free to modify the code but please don't put ; my name under if redistributed. ; ; As a common convention the comments in this source file are Pascal-like ; statements to allow for a better overwiev of the program. ; ; The code is highly optimized to minimize use of memory but without ; compromising the user interface. I don't think it is possible to squeeze ; this code much more than a few bytes, but I would like to hear from ; everybody who succeeds in making this program use less memory (without ; loosing features). Also any other comments about bugs or whatever it might ; be would be very appreciated. ; ; You can reach me with E-mail at the following Internet address: ; ; ehlig@ask.diku.dk ; ; please use subject: 4DOS24H2 ; ; If you cannot reach me through E-mail you can write to the following address: ; ; Niels Jensen ; Vaerebrovej 40,7,3 ; 2880 Bagsvaerd ; Denmark DK ; ; Niels Jensen ; ; -------------------------------------- ; ; ; To re-assemble using Microsoft Macro Assembler (MASM) or Borlands Turbo ; Assembler (TASM): ; ; TASM or MASM 4DOS24H2; ; LINK 4DOS24H2; ; EXE2BIN 4DOS24H2 4DOS24H2.COM ; DEL 4DOS24H2.EXE ; DEL 4DOS24H2.OBJ ; ; If you want 4DOS24H2 to be compatible with the old 40 columns modes change ; the define option on the command line to reflect: ; ; /Dshadow=1 ; ; If you hate shadow simulation change the define option of the command to: ; ; /Dshadow=0 ; ;--- Conditional defines ------------------------+------------------------------ ; The following code causes two shadow columns as default in case nothing or ; a wrong value is specified on the command line. ;------------------------------------------------+------------------------------ IF1 ; IFDEF shadow ; IF (shadow GT 2) + (shadow LT 0) ; Default num. of shadow cols. shadow = 2 ; if not defined. ENDIF ; ELSE ; shadow = 2 ; Default num. of shadow cols. ENDIF ; if value outside prop. range. ENDIF ; ; ;--- Boolean constants --------------------------+------------------------------ False EQU 0 ; True EQU 1 ; ; ;--- Bit constants ------------------------------+------------------------------ Bit7 EQU 80h ; Bit6 EQU 40h ; Bit5 EQU 20h ; Bit4 EQU 10h ; Bit3 EQU 08h ; Bit2 EQU 04h ; Bit1 EQU 02h ; Bit0 EQU 01h ; ; ;--- Colour constants ---------------------------+------------------------------ Black EQU 00h ; Low intensity colours Blue EQU 01h ; Green EQU 02h ; Cyan EQU 03h ; Red EQU 04h ; Magenta EQU 05h ; Brown EQU 06h ; LightGray EQU 07h ; ;------------------------------ Gray EQU 08h ; High intensity colours LightBlue EQU 09h ; LightGreen EQU 0Ah ; LightCyan EQU 0Bh ; LightRed EQU 0Ch ; LightMagenta EQU 0Dh ; Yellow EQU 0Eh ; White EQU 0Fh ; ; ;--- Key Definitions ----------------------------+------------------------------ Enter EQU 0Dh ; Enter-key Escape EQU 1Bh ; Escape-key CtrlC EQU 03h ; Ctrl-C (Ctrl-Break) CtrlP EQU 10h ; Ctrl-P (Printer on/off) ; ;--- Interrupt constants ------------------------+------------------------------ Video EQU 10h ; BIOS Video service Equipmnt EQU 11h ; BIOS Equipment service KeyBoard EQU 16h ; BIOS Keyboard service ReadKey EQU 00h ; BIOS Keyboard: Read key TestKey EQU 01h ; BIOS Keyboard: Test for key Quit EQU 20h ; DOS Service: Terminate DOS EQU 21h ; DOS Service Interrupt GetKeyPress EQU 07h ; DOS Service: Get key (raw) DosReadKey EQU 08h ; DOS Service: Read keystroke PrintStr EQU 09h ; DOS Service: Print String SetVector EQU 25h ; DOS Service: Set int. vector GetVector EQU 35h ; DOS Service: Get int. vector FreeMem EQU 49h ; DOS Service: Free memory blk. BreakInt EQU 23h ; Interrupt 23h (Ctrl-Break) CritErrInt EQU 24h ; Interrupt 24h (Crit. Err.) TSR EQU 27h ; Terminate and stay resident MultiPlex EQU 2Fh ; Multiplex interrupt IDvector EQU 61h ; Vector used for identification ; ;--- Screen related addresses -------------------+------------------------------ MonoSeg EQU 0B000h ; Segment adr. for mono-scr. ColrSeg EQU 0B800h ; Segment adr. for colour-scr. ScrRows EQU 0484h ; Ofs. adr. of screen rows ScrCols EQU 044Ah ; Ofs. adr. of screen columns RegenBufLen EQU 044Ch ; Ofs. adr. of regen.buf.length ; ;--- Response constants -------------------------+------------------------------ IgnoreOK EQU Bit5 ; Set if ignore allowed RetryOK EQU Bit4 ; Set if retry allowed FailOK EQU Bit3 ; Set if fail allowed IgnoreResp EQU 0 ; Response in case of ignore RetryResp EQU 1 ; Response in case of retry AbortResp EQU 2 ; Response in case of abort FailResp EQU 3 ; Response in case of fail ; ;--- Window constants ---------------------------+------------------------------ WinLins EQU 14 ; Num. of lines in window IF shadow EQ 0 WinCols EQU 39 ; Num. of columns in window ELSE IF shadow EQ 1 WinCols EQU 40 ; Num. of columns in window ELSE WinCols EQU 41 ; Num. of columns in window ENDIF ENDIF WinSize EQU WinLins*(WinCols-2) ; Num. of chars in window TopLines EQU 4 ; Num. of lines over window TxtAttr EQU Yellow+(Blue SHL 4) ; Attribute of the window text ; ; Note: Remember to change the colour of the abort-message in the ; window accordingly if you change TxtAttr ; ;--- Misc. Program Constants --------------------+------------------------------ IDsign EQU '4D' ; Identification letters MemSwc EQU 'M' ; Memory information switch ; ;------------------------------------------------+------------------------------ ; ; M A C R O S ; ;------------------------------------------------+------------------------------ PushM MACRO regs ;; Push Multiple registers IRP register,<regs> ;; - Pushes all registers push register ;; between "<" and ">" ENDM ;; separated by commas. ENDM ;; Ex. PushM <ax,bx,cx> ;; PopM MACRO regs ;; Pop Multiple registers IRP register,<regs> ;; - Pops all registers pop register ;; between "<" and ">" ENDM ;; separated by commas. ENDM ;; Ex. PopM <cx,bx,ax> ;------------------------------------------------+------------------------------ ; ; C O D E S T A R T ; ;------------------------------------------------+------------------------------ Code SEGMENT ASSUME CS:Code, DS:Code, ES:Code, SS:Code ;--- PSP addresses ------------------------------+------------------------------ ORG 12h ; - Offset address of old 24h PSP24hOfs LABEL WORD ; handler. ORG 14h ; - Segment address of old 24h PSP24hSeg LABEL WORD ; handler. ORG 16h ; - Segment address of parent ParentPSP LABEL WORD ; PSP. ORG 2Ch ; - Segment address of EnvSegm LABEL WORD ; environment block. ORG 5Ch ; - Offset where resident code FreePSP LABEL WORD ; overlays unused part of PSP. ORG 80h ; - Field indicating parameter ParLen LABEL BYTE ; length ORG 81h ; - Start of command line ParmStr LABEL BYTE ; parameter string ORG 100h ; - Starting offset for COM-prgs. ;------------------------------------------------+------------------------------ Start: JMP Begin ; Go to installation process ORG 100h+FreePSP ; Start offset address 15Ch IDintOfs LABEL NEAR ; If ID-int goto old vect. adr. DB 0EAh ; JMP Far Ptr OldIDvector OldIDvectOfs DW ? ; { Original content of the } OldIDvectSeg DW ? ; { ID-vector. } ; ;--- Variables ----------------------------------+------------------------------ IDword DW IDsign ; Identification word ScrSeg DW ColrSeg ; Screen address. DevHdr LABEL DWORD ; Device Header Pointer DevHdrOfs DW ? ; Address of the device DevHdrSeg DW ? ; in error from BP:SI. Errcode DW ? ; Error code from DI. ; ;--- Error message strings ----------------------+------------------------------ ClrStr DB (WinCols-7) DUP(' '),0 ; Clear string for erasing Msg0 DB 'Disk is write protected',0 ; Disk write protected Msg1 DB 'Unknown unit',0 ; Device not known Msg2a DB 'Disk drive not ready',0 ; Disk drive not ready Msg2b DB 'Device not ready',0 ; Device not ready Msg3 DB 'Unknown command',0 ; Device command unrecognized Msg4 DB 'Data error (CRC)',0 ; Disk data error Msg5 DB 'Bad request struc. length',0; Device call format wrong Msg6 DB 'Seek error',0 ; Disk seek error Msg7 DB 'Unknown media type',0 ; Disk not recognized Msg8 DB 'Sector not found',0 ; Disk sector not found Msg9 DB 'Printer out of paper',0 ; Device out of paper MsgA DB 'Write fault',0 ; Device write fault MsgB DB 'Read fault',0 ; Device read fault MsgC DB 'General failure',0 ; Disk general error MsgF DB 'Invalid disk change',0 ; Disk is replaced Msg10h DB 'FCB unavailable',0 ; Device error Msg11h DB 'Sharing buffer overflow',0 ; Device error MsgU DB 'Unknown error',0 ; Wrong error code ; ErrMsg DW Msg0, Msg1, Msg2a, Msg3, Msg4; String pointer table with DW Msg5, Msg6, Msg7, Msg8, Msg9 ; pointers to the error DW MsgA, MsgB, MsgC, MsgU, MsgU ; messages DW MsgF, Msg10h, Msg11h ; ; ;--- Disk error message parts -------------------+------------------------------ DskMsg1 DB 'Disk ',0 ; DskMsg2A DB 'read ',0 ; DskMsg2B DB 'write ',0 ; DskMsg3 DB 'error on drive ' ; Drive DB 'A: in ',0 ; DskMsg4A DB 'DOS system area',0 ; DskMsg4B DB 'FAT-area (File Allocation Table)',0 DskMsg4C DB 'the root directory area',0 ; DskMsg4D DB 'the data area',0 ; DskMsg4 DW DskMsg4A,DskMsg4B,DskMsg4C,DskMsg4D ; ;--- Device error message parts -----------------+------------------------------ DevMsg1 DB 'Device error on device ',0 ; DevMsg2 DB 'Memory copy of FAT is bad',0; ; ;--- Basic message window -----------------------+------------------------------ IF shadow EQ 0 MsgBuf DB '┌──── DOS Critical Error Handler ────┐' DB '│ Version 2.00 │' DB '│ │' DB '│ ' MsgPos1 DB ' │' DB '│ ' MsgPos2 DB ' │' DB '│ │' DB '│ Error: ' MsgPos3 DB ' │' DB '│ │' DB '│ Please hit: │' DB '│ A - to Abort current operation │' DB '│ R - to Retry the operation │' DB '│ ' MsgPos5 DB ' │' DB '│ ' MsgPos6 DB ' │' DB '└─────────────────────────────────────┘' ELSE IF shadow EQ 1 MsgBuf DB '┌──── DOS Critical Error Handler ────┐' DB '│ Version 2.00 │ ' DB '│ │ ' DB '│ ' MsgPos1 DB ' │ ' DB '│ ' MsgPos2 DB ' │ ' DB '│ │ ' DB '│ Error: ' MsgPos3 DB ' │ ' DB '│ │ ' DB '│ Please hit: │ ' DB '│ A - to Abort current operation │ ' DB '│ R - to Retry the operation │ ' DB '│ ' MsgPos5 DB ' │ ' DB '│ ' MsgPos6 DB ' │ ' DB '└─────────────────────────────────────┘ ' DB ' ' ELSE MsgBuf DB '┌──── DOS Critical Error Handler ────┐' DB '│ Version 2.00 │ ' DB '│ │ ' DB '│ ' MsgPos1 DB ' │ ' DB '│ ' MsgPos2 DB ' │ ' DB '│ │ ' DB '│ Error: ' MsgPos3 DB ' │ ' DB '│ │ ' DB '│ Please hit: │ ' DB '│ A - to Abort current operation │ ' DB '│ R - to Retry the operation │ ' DB '│ ' MsgPos5 DB ' │ ' DB '│ ' MsgPos6 DB ' │ ' DB '└─────────────────────────────────────┘ ' DB ' ' ENDIF ENDIF ; ;--- Response message parts ---------------------+------------------------------ ; RetryMsg DB 'R - to Retry the operation',0; ; RetryMsgLen EQU $-RetryMsg-1 ; IgnoreMsg DB 'I - to Ignore the error ',0; IgnoreMsgLen EQU $-IgnoreMsg-1 ; FailMsg DB 'F - to Fail the operation',0; ; ;------------------------------------------------+------------------------------ ; ; S U B R O U T I N E S ; ;------------------------------------------------------------------------------- ; S w a p ;------------------------------------------------------------------------------- ; Does : Swaps the buffer containing the message window with the data on ; the screen located where the window is to be displayed. ; On call : DS:SI = Source; ES:DI = Destination (MsgBuf/Screen) ; Uses : BX, BP, CX, SI, DI ; Changes : BX, BP, CX, SI, DI ; ;--- Start of Swap ------------------------------+------------------------------ Swap PROC NEAR ; Procedure Swap; ; begin MOV SI, Offset MsgBuf ; ds:si:= MsgBuf; MOV DI, DX ; es:di:= Scr; IF shadow EQ 0 MOV CX, WinLins ; cx:= WinLins; ELSE MOV CX, WinLins+1 ; cx:= WinLins+1; ENDIF Loop1: PUSH CX ; for cx1:= WinLins+1 downto 1 do IF shadow NE 0 MOV AX, CX ; DEC AX ; ax:= cx1 - 1; ENDIF MOV CL, WinCols ; if (cx1 = WinLins+1) or IF shadow NE 0 JE NoShadC ; (cx1 = 1) CMP AL, WinLins-1 ; then tmp:= WinCols JBE Loop11 ; else tmp:= WinCols+1; IF shadow EQ 1 NoShadC: DEC CX ; ELSE NoShadC: SUB CL, 2 ; for cx2:= tmp downto 1 do begin ENDIF ENDIF Loop11: MOV BX, ES:[DI] ; bx:= Scr[ds:si]; IF shadow NE 0 CMP AL, WinLins-1 ; if (cx1 <= WinLins) JA NoShade ; then OR AX, AX ; if (cx2 <= 2) or JZ Shade ; (cx1 = 1) IF shadow EQ 1 CMP CL, 1 ; JNE NoShade ; ELSE CMP CL, 2 ; JA NoShade ; ENDIF Shade: MOV [SI], BL ; then Buf[si]:= bl; ENDIF NoShade: MOVSW ; Scr[di]:= Buf[si]; MOV [SI-2], BX ; di:= di+2; si:= si+2; LOOP Loop11 ; Buf[si-2]:= bx ; end; (* for cx2 ... *) IF shadow NE 0 CMP AL, WinLins ; if (ax = WinLins) or JE Adj ; (ax = 1) CMP AL, 1 ; JNE NoAdj ; then IF shadow EQ 1 Adj: INC DI ; INC DI ; di:= di + 2; ELSE Adj: ADD DI, 4 ; di:= di + 4; ENDIF ENDIF NoAdj: ADD DI, BP ; di:= di + bp; POP CX ; LOOP Loop1 ; end (* for cx1 ... *) RET ; end; Swap ENDP ; ;------------------------------------------------+------------------------------ ; P u t S t r ;------------------------------------------------------------------------------- ; Does : Displays a null-teminated string. Length must be greater than 0. ; On call : AH = Attribute Byte; ; DS:SI = ^Source; ; ES:DI = ^Destination (Screen memory) ; Uses : AX, SI, DI, DS, ES ; Changes : AL, SI, DI ; ;------------------------------------------------+------------------------------ PutStr PROC NEAR ; Procedure PutStr; again: LODSB ; begin STOSW ; repeat CMP Byte Ptr [SI], 0 ; al:= Buf[si]; write(ax); JNE again ; Inc(si) RET ; until Buf[si] = 0 PutStr ENDP ; end; ;------------------------------------------------+------------------------------ ; ; N e w i n t e r r u p t h a n d l e r ; ;------------------------------------------------------------------------------- ; ; In case of a critical error during a graphics session this handler would ; not behave normaly because the information window is written directly to ; the screen memory. Instead the handler checks for graphics modes and ; calls the old critical error handler in case the current mode is not a ; text mode. ; ; Graphics modes are detected automatically by checking the length of the ; screen regenerate buffer and compare it against the (last) text screen ; solution. This is only tested on a Tseng ET4000 based Super VGA card and ; therefore NOT garanteed to work with other display adapters. ; ; ; Special register use: ; ; BP: Holds the constant 2*(ScrCols-WinCols) used during swapping of ; the message window and the screen. The constant expresses the ; byte distance in display memory from the end of a line in the ; message window to the beginning of the next. ; ; DX: Holds the constant (TopLines*2*ScrCols + 2*Indent) which is the ; offset from the start of display memory to the upper left corner ; of the message window. ; ;------------------------------------------------+------------------------------ New24h: PushM <BX,CX,DX,SI,DI,BP,DS,ES>; Save(registers); PUSH AX ; {AX = error locus info} PUSH CS ; ds:= cs; POP DS ; {BP:SI => dev. drv. header} MOV DevHdrOfs, SI ; DevHdrOfs:= si; MOV DevHdrSeg, BP ; DevHdrSeg:= bp; AND DI, 001Fh ; di:= di and 001Fh; MOV ErrCode, DI ; ErrCode:= di; XOR DX, DX ; dx:= 0; MOV ES, DX ; es:= dx; ;--- Check for graphics mode --------------------------------------------------- Patch1 LABEL WORD ; { Address for patching } MOV AL, 24 ; {$IF EGA} al:= ScrRows-1; NOP ; {$ELSE} al:= 24; NOP ; {$ENDIF} INC AX ; al:= al+1; MUL Byte Ptr ES:ScrCols ; ax:= ScrRows*ScrCols; SHL AX, 1 ; ax:= ax*2; MOV DX, ES:RegenBufLen ; dx:= RegenBufLength; SHR DX, 1 ; dx:= dx/2; JZ OldHandler ; if (dx=0) or (ax<=dx) CMP AX, DX ; then begin JA TxtMode ; { Jump to old handler } OldHandler: PopM <AX,ES,DS,BP,DI,SI,DX,CX,BX>; Rest(regs); DB 0EAh ; JMP Far Ptr OldHandler OldInt24hOfs DW ? ; { Pointer to original } OldInt24hSeg DW ? ; { int 24h handler } ; end; ;--- Calculate top margin and window start position ---------------------------- TxtMode: MOV AX, ES:ScrCols ; ax:= ScrCols; MOV BP, AX ; bp:= ax; SUB BP, WinCols ; bp:= ScrCols - WinCols; MOV AH, TopLines*2 ; {Calc. byte cnt for topmarg} MUL AH ; ax:= TopLines * 2*ScrCols; ADD AX, BP ; ax:= ax + Indent; SHL BP, 1 ; bp:= 2 * bp; MOV DX, AX ; dx:= ax; { Window start pos } IF (WinCols AND 1) ; if Odd(WinCols) DEC DX ; then dx:= dx - 1; ENDIF ; PUSH CS ; { Setup ES } POP ES ; es:= cs; ;--- Test bit 7 for disk error ------------------------------------------------- POP BX ; { Get org. AX in BX } PUSH BX ; bx:= ErrInfo; MOV AH, TxtAttr ; ah:= TxtAttr; MOV DI, Offset MsgPos1 ; di:= MsgPos1; TEST BH, Bit7 ; if DiskError JNZ GetName ; then begin ;--- Put disk error message ---------------------------------------------------- MOV ErrMsg[2*2], Offset Msg2a; ErrMsg[2]:= Msg2a; MOV SI, Offset DskMsg1 ; si:= ^DskMsg1; CALL PutStr ; PutStr(si,di); ;--- Get error type info from bit 0 -------------------------------------------- TEST BH, Bit0 ; if WriteError MOV SI, Offset DskMsg2A ; then si:= ^DskMsg2B JZ ReadError ; else si:= ^DskMsg2A; MOV SI, Offset DskMsg2B ; PutStr(si,di); ReadError: CALL PutStr ; { Patch drive letter } ADD Drive, BL ; Inc(DskMsg3[Drv],cl); MOV SI, Offset DskMsg3 ; si:= ^DskMsg3; CALL PutStr ; PutStr(si,di); MOV Drive, 'A' ; DskMsg3[Drv]:= 'A'; ;--- Get error area info from bits 1 and 2 ------------------------------------- MOV DI, Offset MsgPos2 ; di:= MsgPos2; PUSH DI ; MOV BL, BH ; AND BX, 0006h ; bx:= bx mod 7; MOV SI, Offset ClrStr ; si:= Ofs(ClrStr); CALL PutStr ; PutStr(si,di); POP DI ; di:= MsgPos2; MOV SI, DskMsg4[BX] ; si:= DskMsg4[bx]; CALL PutStr ; PutStr(si,di) JMP Short GetError ; end ;--- Device error - test bit 15 of device attribute for char/blok device ------- GetName: MOV ErrMsg[2*2], Offset Msg2b; else begin PUSH ES ; ErrMsg[2]:= Msg2b; LES SI, DevHdr ; es:si:= ^DeviceHeader; MOV CX, ES:[SI+4] ; cx:= DeviceAttr; MOV SI, Offset DevMsg1 ; TEST CH, Bit7 ; if CharDevice JNZ CharDev ; then si:= DevMsg1 MOV SI, Offset DevMsg2 ; else si:= DevMsg2; CharDev: POP ES ; CALL PutStr ; PutStr(si,di); TEST CH, Bit7 ; JZ ClrMsgPos2 ; if CharDevice PUSH DS ; then begin {Get dev. name} LDS SI, DevHdr ; ds:si:= ^DeviceName; ADD SI, 10 ; for cx1:= 1 to 8 do begin MOV CX, 8 ; Win[di]:= DevName[si+10]; GetLoop1: LODSB ; Inc(di); Inc(si) STOSW ; end LOOP GetLoop1 ; end; POP DS ; si:= ClrStr; ClrMsgPos2: MOV SI, Offset ClrStr ; di:= MsgPos2; MOV DI, Offset MsgPos2 ; PutStr(si,di) CALL PutStr ; end; ;--- Generate specific error information --------------------------------------- GetError: MOV DI, Offset MsgPos3 ; di:= MsgPos3; MOV SI, Offset ClrStr+6 ; si:= SubStr(6,ClrStr); CALL PutStr ; PutStr(si,di); MOV DI, Offset MsgPos3 ; di:= MsgPos3; MOV SI, Offset MsgU ; CMP ErrCode, 0011h ; JA NoValidCode ; if ErrCode > 11h MOV SI, ErrCode ; then si:= MsgU { Unkn. err. } SHL SI, 1 ; else si:= ErrMsg[ErrCode]; MOV SI, ErrMsg[SI] ; NoValidCode: CALL PutStr ; PutStr(si,di); ;--- Find out what response is allowed ----------------------------------------- MOV SI, Offset ClrStr ; si:= ClrStr; MOV DI, Offset MsgPos6 ; di:= MsgPos6; CALL PutStr ; PutStr(si,di); POP BX ; bx:= errlocus; MOV DI, Offset MsgPos5 ; { Test for retry } ; MOV DI, Offset MsgPos4 ; { Test for retry } ;TestRetry: ; ; TEST BH, RetryOK ; if RetryOK ; JZ TestIgnore ; then begin ; MOV SI, Offset RetryMsg ; PutStr(RetryMsg); ; CALL PutStr ; di:= NextPos ; ADD DI, 2*(WinCols-RetryMsgLen); TestIgnore: ; end; TEST BH, IgnoreOK ; if IgnoreOK JZ TestFail ; then begin MOV SI, Offset IgnoreMsg ; PutStr(IgnoreMsg); CALL PutStr ; di:= NextPos ADD DI, 2*(WinCols-IgnoreMsgLen); TestFail: ; end; MOV SI, Offset ClrStr+3 ; if FailOK TEST BH, FailOK ; then si:= FailMsg JZ EndRespTst ; else si:= ClrStr; MOV SI, Offset FailMsg ; EndRespTst: CALL PutStr ; PutStr(SI,DI); ;--- Show message window ------------------------------------------------------- MOV ES, ScrSeg ; es:= ScrSeg; PUSH BX ; CALL Swap ; Swap(Screen,MsgBuf); POP BX ; ;--- Get user response --------------------------------------------------------- GetKey: MOV AH, TestKey ; { Get keystroke } INT KeyBoard ; repeat JZ GetKey ; while not KeyPrs do CMP AL, CtrlP ; TestKey(al); JNE NormalKey ; if al = '^P' MOV AH, DosReadKey ; then INT Dos ; DosReadKey(al) JMP Short GetKey ; until al <> '^P'; NormalKey: MOV AH, ReadKey ; INT Keyboard ; ReadKey(al); SUB AL, 'A' ; CMP AL, ('Z'-'A') ; if al in ['A'..'Z'] JA ProcessIgnore ; then ADD AL, 20h ; al:= LowCase(al); ;--- Process response ---------------------------------------------------------- ; case al of ProcessIgnore: CMP AL, ('i'-'A') ; 'i': begin {** Ignore **} JNE ProcessRetry ; if Not IgnoreOK TEST BH, Bit5 ; then goto GetKey; JZ GetKey ; al:= 0; MOV AL, IgnoreResp ; end; ProcessRetry: CMP AL, ('r'-'A') ; 'r', JE RetryAct ; CMP AL, (Enter-'A') ; Enter, JE RetryAct ; CMP AL, (' '-'A') ; ' ': begin {** Retry **} JNE ProcessFail ; al:= 1 RetryAct: MOV AL, RetryResp ; end; ;TEST BH, Bit4 ; if Not RetryOK ;JZ GetKey ; then goto GetKey; ProcessFail: CMP AL, ('f'-'A') ; 'f': begin {** Fail **} JNE ProcessAbort ; if Not IgnoreOK TEST BH, Bit3 ; then goto GetKey JZ GetKey ; al:= 3; MOV AL, FailResp ; end; ProcessAbort: CMP AL, ('a'-'A') ; 'a', JE AbortAct ; CMP AL, ('q'-'A') ; 'q', JE AbortAct ; CMP AL, ('x'-'A') ; 'x', JE AbortAct ; CMP AL, (CtrlC-'A') ; ^C , JE AbortAct ; CMP AL, (Escape-'A') ; Esc: begin {** Abort **} JNE ElseCase ; AL:= 2 AbortAct: MOV AL, AbortResp ; end; ElseCase: CMP AL, FailResp ; else goto GetKey JA GetKey ; end; { case } ;--- Restore screen and exit --------------------------------------------------- PUSH AX ; CALL Swap ; Swap(MsgBuf,Screen); POP AX ; XOR AH, AH ; ah:= 0; POPM <ES,DS,BP,DI,SI,DX,CX,BX>; Rest(regs) IRET ; end; EndOfCode EQU $ ; ;----------------------------------------------+-------------------------------- ; ; E N D O F R E S I D E N T C O D E ; ;------------------------------------------------------------------------------- ; L o a d e r - p r o g r a m ; ; This part of the code is responsible for: ; - loading the handler ; - high load without trouble under 386Max or QEMM if required ; - detection of screen hardware ; - the handler being continuously active during shells ; ;------------------------------------------------+------------------------------ ; P R O C E D U R E D E C L A R A T I O N S ;------------------------------------------------+------------------------------ ; Procedure WriteInt (ax: int); ;------------------------------------------------+------------------------------ WriteInt PROC NEAR ; Procedure WriteInt (ax:int); PushM <AX,BX,CX,DX,BP> ; { Writes int w/o leading 0 } MOV BX, 0007h ; begin MOV BP, 10000 ; bp:= 10000; XOR CX, CX ; cx:= 0; WriteLoop: XOR DX, DX ; repeat DIV BP ; dx:= ax mod bp; PUSH DX ; ax:= ax div bp; ADD CL, AL ; cl:= cl + al; JZ LeadZero ; if cl > 0 ADD AL, '0' ; then begin MOV AH, 0Eh ; al:= Char(al); INT Video ; write(al) LeadZero: MOV AX, BP ; end; MOV BP, 10 ; XOR DX, DX ; dx:= 0; DIV BP ; bp:= bp div 10; MOV BP, AX ; POP AX ; ax:= dx CMP BP, 0 ; until bp <= 0; JG WriteLoop ; end; PopM <BP,DX,CX,BX,AX> ; RET ; WriteInt ENDP ; ;------------------------------------------------+------------------------------ ; Procedure WriteHex (ax: int); ;------------------------------------------------+------------------------------ WriteHex PROC NEAR ; Procedure WriteHex (ax:int); PushM <BX,CX,DX,AX> ; begin MOV AH, 2 ; ah:= 2; MOV CX, 4 ; cx:= 4; WriteLoop1: POP BX ; for i:= 1 to cx do begin ROL BX, 1 ; bx:= Rotate(bx,1); ROL BX, 1 ; bx:= Rotate(bx,1); ROL BX, 1 ; bx:= Rotate(bx,1); ROL BX, 1 ; bx:= Rotate(bx,1); PUSH BX ; AND BX, 000Fh ; bx:= bx mod 16; MOV DL, HexCif[BX] ; dl:= HexCif[bx]; INT Dos ; write(dl); LOOP WriteLoop1 ; end PopM <AX,DX,CX,BX> ; end; RET ; ;------------------------------------------------+ { Local constant } HexCif DB '0123456789ABCDEF' ; const HexCif = '0..9ABCDEF'; WriteHex ENDP ; ;------------------------------------------------+------------------------------ ;--- Test if already installed ------------------------------------------------- Begin: ; begin MOV AL, CritErrInt ; MOV AH, GetVector ; INT Dos ; GetVect(CritErrInt,es:bx); PUSH ES ; Save(Int24hSeg); PUSH BX ; Save(Int24hOfs); ; { Install by modifying PSP } MOV PSP24hOfs, Offset New24h ; PSP24hOfs:= Ofs(New24h); MOV AH, GetVector ; { See if already installed } MOV AL, IDvector ; GetVect(IDvector,es:bx); INT Dos ; CMP ES:IDword, IDsign ; if es:IDword = IDsign JNE NotInst ; then begin ;--- Handler already installed ------------------------------------------------- ; { Reinstall handler } MOV PSP24hSeg, ES ; PSP24hSeg:= es; ; { Update stored address } ; { of old handler. } POP ES:OldInt24hOfs ; Rest(es:OldInt24hOfs); POP ES:OldInt24hSeg ; Rest(es:OldInt24hSeg); MOV AX, 4C00h ; Halt(0) INT Dos ; end; ;--- Handler not installed ----------------------------------------------------- NotInst: MOV DX, Offset ProgInfo ; { Print program info } MOV AH, PrintStr ; write(ProgInfo); INT Dos ; MOV AX, 0D44Dh ; { Test if 4DOS is present } XOR BX, BX ; ax:= 0D44Dh; INT MultiPlex ; bx:= 0; CMP AX, 44DDh ; MultiPlex(ax,bx); JE Found4DOS ; if ax <> 44DDh MOV DX, Offset LoadErr1 ; then begin MOV AH, PrintStr ; { 4DOS not found } INT Dos ; write(LoadErr1); MOV AH, GetKeyPress ; { Wait for key press } INT Dos ; GetKeyPress; MOV AX, 4C01h ; Halt(1) INT Dos ; end Found4DOS: ; { Install by modifying PSP } POP OldInt24hOfs ; OldInt24hOfs:= Int24hOfs; POP OldInt24hSeg ; OldInt24hSeg:= Int24hSeg; ; MOV BX, CS ; { Calc. new segm. value } SUB BX, 10h ; MOV PSP24hSeg, BX ; PSP24hSeg:= Seg(New24h); ;--- Release Environment Block ------------------------------------------------- MOV ES, CS:EnvSegm ; { Release environm. block } MOV AH, FreeMem ; ES:= ^Env; INT Dos ; FreeMem(ES); ;--- Screen-Detection ---------------------------------------------------------- MOV AH, 12h ; { Test for EGA+ adapter } MOV BL, 10h ; bl:= 10h; INT Video ; GetEGAinfo(bl); CMP BL, 10h ; if bl <> 10h JE TestCOorBW ; then begin MOV Patch1, 0A026h ; PatchByte(Patch1); MOV [Patch1+2], 0484h ; PatchByte(Patch1+2) TestCOorBW: ; end; INT Equipmnt ; BIOS(Equip); TEST AX, Bit5+Bit4 ; if Bit4 and Bit5 JNP EndDetect ; then ScrSeg:= MonoSeg MOV ScrSeg, MonoSeg ; else ScrSeg:= ColrSeg; EndDetect: ; ;--- Test for memory info switch as paramter ----------------------------------- MOV SI, Offset ParmStr ; si:= Ofs(ParmStr); XOR CX, CX ; cx:= Length(ParmStr); MOV CL, ParLen ; if cx <> 0 JCXZ NoMemStat ; then begin ; { ParmStr[1] always space } ; { or switch char ('/'). } ParTest: INC SI ; repeat OR Byte Ptr [SI], 20h ; Inc(si); Dec(cx); SwcTest: CMP Byte Ptr [SI], (MemSwc or 20h);LowCase([si]); LOOPNE ParTest ; until ([si]=MemSwc)or(cx=0); JNE NoMemStat ; if [si] = MemSwc ;--- Print Memory Statistics --------------------------------------------------- MOV DX, Offset MemInfo ; then begin MOV AH, PrintStr ; { Print memory status } INT Dos ; write(MemInfo); MOV AX, CS ; { Print load address } CALL WriteHex ; WriteHex(CS); MOV DX, Offset MemInfo1 ; MOV AH, PrintStr ; { Print memory usage } INT Dos ; write(MemInfo1); MOV AX, Offset EndOfCode-100h; CALL WriteInt ; WriteInt(EndOfCode-100); MOV DX, Offset MemInfo2 ; MOV AH, PrintStr ; writeln(MemInfo2); INT Dos ; writeln; ; end NoMemStat: ; end; ;--- Install Identification mark ----------------------------------------------- MOV AL, IDvector ; { Install identification } MOV AH, GetVector ; GetVector(IDvect,es:bx); INT Dos ; OldIDvectSeg:= es; MOV OldIDvectOfs, BX ; OldIDvectOfs:= bx; MOV OldIDvectSeg, ES ; PUSH DS ; Save(ds); {!} MOV DS, PSP24hSeg ; ds:= Seg(IDintSeg); MOV DX, Offset IDintOfs ; dx:= Ofs(IDintOfs); MOV AH, SetVector ; SetVect(IDvect,ds:dx); INT Dos ; ;--- High Load precautions under QEMM and 386Max ------------------------------- PUSH DS ; { Modify parent PSP. } MOV DS, CS:ParentPSP ; ds:= Seg(ParentPSP); MOV PSP24hOfs, Offset New24h ; ds:PSP24hOfs:= Ofs(New24h); POP PSP24hSeg ; ds:PSP24hSeg:= Seg(New24h); POP DS ; Rest(ds); ;--- Move code to overlay unused part of PSP ----------------------------------- PUSH CS ; { Overlay FCB-area and POP ES ; parameters to save mem. } MOV DI, Offset FreePSP ; di:= Ofs(FreePSP); MOV SI, Offset IDintOfs ; si:= Ofs(code); MOV CX, Offset EndOfCode-IDintOfs; cx:= EndOfCode-IDintOfs; CLD ; for i:= 0 to cx-1 do REP MOVSB ; Mem[di+i]:= Mem[si+i]; ;--- Terminate and Stay Resident ----------------+------------------------------ MOV DX, Offset EndOfCode-(IDintOfs-FreePSP) INT TSR ; Keep ; end. ;----------------------------------------------+-------------------------------- ProgInfo DB '4DOS Critical Error Handler Version 2.00, rev. B',10,13 DB 'Written by Niels Jensen - May, 1993',13,10,'$' MemInfo DB 'Resident at address $' MemInfo1 DB ':0000 (hex) consuming $' MemInfo2 DB ' bytes of memory.',13,10,'$' LoadErr1 DB 10 DB 'The critical error handler is not installed due to an error.',13,10,10 DB 'The running command interpreter is not a version of 4DOS or NDOS.',10,13 DB 'You need the 4DOS or NDOS command interpreter from JP Software to',10,13 DB 'use this handler - it will not work under COMMAND.COM.',13,10,10 DB 'Press any key to continue . . .$' ;------------------------------------------------+------------------------------ Code ENDS END Start