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Text File | 1991-02-14 | 38.2 KB | 1,000 lines

.modeL small, pascal, os_dos INCLUDE demo.inc .DATA _psp PSEG ? ; Segment of PSP _env PSEG ? ; Segment of environment .CODE ;* WinOpen - Saves portion of screen to allocated memory, then opens a window ;* with specified fill attribute. See also the WinClose procedure. ;* ;* Shows: DOS Function - 48h (Allocate Memory Block) ;* Instructions - movsw stosw rep ;* ;* Uses: vconfig - Video configuration structure (initialized ;* by calling the GetVidConfig procedure) ;* ;* Params: Row1 - Row at top of window ;* Col1 - Column at left edge of window ;* Row2 - Row at bottom of window ;* Col2 - Column at right edge of window ;* Attr - Fill attribute for window ;* ;* Return: Short integer with segment address of allocated buffer, or ;* 0 if unable to allocate memory WinOpen PROC USES ds di si, Row1:WORD, Col1:WORD, Row2:WORD, Col2:WORD, Attr:WORD GetVidOffset Row1, Col1 ; Get offset in video segment mov si, ax ; SI = video offset for window mov bx, Row2 sub bx, Row1 inc bx ; BX = number of window rows mov cx, Col2 sub cx, Col1 inc cx ; CX = number of columns mov ax, cx ; Compute number of video mul bl ; cells in window add ax, 3 ; Plus 3 additional entries shr ax, 1 ; Shift right 3 times to shr ax, 1 ; multiply by 2 bytes/cell, shr ax, 1 ; divide by 16 bytes/paragraph inc ax ; Add a paragraph push bx ; Save number of rows mov bx, ax ; BX = number of paragraphs mov ah, 48h ; Request DOS Function 48h int 21h ; Allocate Memory Block pop bx .IF carry? ; If unsuccessful, sub ax, ax ; return null pointer .ELSE mov es, ax ; Point ES:DI to allocated sub di, di ; buffer mov ax, si stosw ; Copy video offset to buffer mov ax, bx stosw ; Number of rows to buffer mov ax, cx stosw ; Number of cols to buffer mov ax, 160 ; Number of video cells/row mov ds, vconfig.sgmnt ; DS = video segment .REPEAT push si ; Save ptr to start of line push cx ; and number of columns ; For CGA adapters, WinOpen avoids screen "snow" by disabling the video prior ; to block memory moves, then reenabling it. Although this technique can ; result in brief flickering, it demonstrates the fastest way to access a ; block in the CGA video buffer without causing display snow. See also the ; StrWrite procedure for another solution to the problem of CGA snow. .IF vconfig.adapter == CGA ; If not CGA adapter, INVOKE DisableCga ; disable video .ENDIF rep movsw ; Copy one row to buffer .IF vconfig.adapter == CGA ; If CGA adapter, INVOKE EnableCga ; reenable CGA video .ENDIF pop cx ; Recover number of columns pop si ; and start of line add si, ax ; Point to start of next line dec bx ; Decrement row counter .UNTIL zero? ; Until no rows remain ; Screen contents (including display attributes) are now copied to buffer. ; Next open window, overwriting the screen portion just saved. mov ax, 0600h ; Scroll service mov bh, BYTE PTR Attr ; Fill attribute mov cx, Col1 ; CX = row/col for upper left mov ch, BYTE PTR Row1 mov dx, Col2 ; DX = row/col for lower right mov dh, BYTE PTR Row2 int 10h ; Blank window area on screen mov ax, es ; Return address of allocated .ENDIF ; segment ret WinOpen ENDP ;* WinClose - "Closes" a window previously opened by the WinOpen procedure. ;* See also the WinOpen procedure. ;* ;* Shows: DOS Function - 49h (Release Memory Block) ;* Instructions - lodsw ;* Operators - : (segment override) SEG ;* ;* Uses: vconfig - Video configuration structure (initialized ;* by calling the GetVidConfig procedure) ;* ;* Params: Adr - Segment address of buffer that holds screen contents ;* saved in WinOpen procedure ;* ;* Return: None WinClose PROC USES ds di si, Adr:WORD mov ds, Adr ; DS:SI points to buffer sub si, si lodsw mov di, ax ; DI = video offset of window lodsw mov bx, ax ; BX = number of window rows lodsw mov cx, ax ; CX = number of columns mov ax, SEG vconfig.sgmnt mov es, ax ; Point ES to data segment push es:vconfig.sgmnt pop es ; ES = video segment mov ax, 160 ; Number of video cells/row .REPEAT push di ; Save ptr to start of line push cx ; and number of columns ; Disable CGA video prior to memory move to avoid screen snow. (See the ; WinOpen and StrWrite procedures for further discussions on CGA snow.) .IF vconfig.adapter == CGA ; If CGA adapter, INVOKE DisableCga ; disable video .ENDIF rep movsw ; Copy one row to buffer .IF vconfig.adapter == CGA ; If CGA adapter, INVOKE EnableCga ; reenable CGA video .ENDIF pop cx ; Recover number of columns pop di ; and start of line add di, ax ; Point to start of next line dec bx ; Decrement row counter .UNTIL zero? ; until no rows remain mov ah, 49h ; Request DOS Function 49h mov es, Adr int 21h ; Release Memory Block ret WinClose ENDP ;* SetCurSize - Sets cursor size. ;* ;* Shows: BIOS Interrupt - 10h, Function 1 (Set Cursor Type) ;* ;* Params: Scan1 - Starting scan line ;* Scan2 - Ending scan line ;* ;* Return: None SetCurSize PROC, Scan1:WORD, Scan2:WORD mov cx, Scan2 ; CL = ending scan line mov ch, BYTE PTR Scan1 ; CH = starting scan line mov ah, 1 ; Function 1 int 10h ; Set Cursor Type ret SetCurSize ENDP ;* GetCurSize - Gets current cursor size. ;* ;* Shows: BIOS Interrupt - 10h, Function 3 (Get Cursor Position) ;* ;* Uses: vconfig - Video configuration structure (initialized ;* by calling the GetVidConfig procedure) ;* ;* Params: None ;* ;* Return: Short integer with high byte = top scan line, ;* low byte = bottom scan line GetCurSize PROC mov ah, 3 ; Function 3 mov bh, vconfig.dpage int 10h ; Get Cursor Position mov ax, cx ; Return cursor size ret GetCurSize ENDP ;* GetShift - Gets current shift status. Checks for extended keyboard, ;* and, if available, returns additional shift information. ;* ;* Shows: BIOS Interrupt - 16h, Functions 2 and 12h (Get Keyboard Flags) ;* ;* Params: None ;* ;* Return: Long integer ;* high word = 0 for nonextended keyboard ;* 1 for extended keyboard ;* low word has following bits set when indicated keys are pressed: ;* 0 - Right SHIFT 8 - Left CTRL ;* 1 - Left SHIFT 9 - Left ALT ;* 2 - CTRL 10 - Right CTRL ;* 3 - ALT 11 - Right ALT ;* 4 - SCROLL LOCK active 12 - SCROLL LOCK pressed ;* 5 - NUM LOCK active 13 - NUM LOCK pressed ;* 6 - CAPS LOCK active 14 - CAPS LOCK pressed ;* 7 - INSERT toggled 15 - SYS REQ pressed GetShift PROC sub dx, dx ; Assume nonextended keyboard mov ah, 2 ; and use Function 2 mov es, dx ; Point ES to low memory .IF BYTE PTR es:[496h] & 16 ; If extended keyboard installed, inc dx ; set high word of return code mov ah, 12h ; and use Function 12h .ENDIF int 16h ; Get Keyboard Flags ret GetShift ENDP ;* GetKeyClock - Waits for keystroke while updating time at specified location ;* on screen. ;* ;* Shows: BIOS Interrupt - 16h, Functions 0 and 10h (Read Character) ;* 16h, Functions 1 and 11h (Get Keyboard Status) ;* DOS Functions - 2Ah (Get Date) ;* 2Ch (Get Time) ;* ;* Uses: vconfig - Video configuration structure (initialized ;* by calling the GetVidConfig procedure) ;* ;* Params: Row - Screen row for clock display ;* Col - Screen column for clock display ;* ;* Return: Short integer with key scan code in high byte and ASCII ;* character code in low byte. Low byte is 0 for special ;* keys (such as the "F" keys), which don't generate characters. .DATA PUBLIC datestr datestr BYTE " - - : : ", 0 ; Date/time string .CODE GetKeyClock PROC, Row:WORD, Col:WORD LOCAL service:BYTE INVOKE GetShift ; Check for extended keyboard mov service, 11h ; Assume Function 11h .IF dx != 1 ; If no extended keyboard, mov service, 1 ; use Function 1 .ENDIF .WHILE 1 mov ah, service int 16h ; Get Keyboard Status .BREAK .IF !zero? ; If no key yet, update clock ; If not monochrome, color text, or black and white, skip clock update ; and poll keyboard again. .CONTINUE .IF (vconfig.mode != 7) \ && (vconfig.mode != 3) \ && (vconfig.mode != 2) ; If 80-column text, get date and time from DOS before again ; polling keyboard, and display at upper right corner of screen. mov ah, 2Ch ; Request time int 21h ; Get Time mov dl, dh push dx ; Save seconds, push cx ; minutes, mov cl, ch ; and push cx ; hours mov ah, 2Ah ; Request date int 21h ; Get Date sub cx, 1900 ; Subtract century, CL = year push cx ; Save year, push dx ; day, mov dl, dh ; and push dx ; month mov cx, 6 sub bx, bx .REPEAT pop ax ; Recover all 6 numbers in AL aam ; Convert to unpacked BCD xchg al, ah ; Switch bytes for word move or ax, "00" ; Make ASCII numerals mov WORD PTR datestr[bx], ax; Copy to string add bx, 3 ; at every third byte .UNTILCXZ INVOKE StrWrite, Row, Col, ADDR datestr .ENDW ; Loop again for keypress mov ah, service ; 1 or 11h, depending on keybd dec ah ; Set AH to 0 or 10h int 16h ; Get key to remove it from ret ; keyboard buffer GetKeyClock ENDP ;* GetPSP - Gets address of Program Segment Prefix. For DOS 3.0 or higher. ;* ;* Shows: DOS Function - 62h (Get PSP Address) ;* Instruction - call ;* ;* Params: None ;* ;* Return: Short integer with PSP segment address ;* or 0 if DOS version below 3.0 GetPSP PROC INVOKE GetVer ; Get DOS version number .IF ax >= 300 ; If DOS 3.0 or higher: mov ah, 62h ; query DOS for PSP, int 21h ; get PSP Address, mov ax, bx ; return in AX .ELSE ; Else 2.0: sub ax, ax ; For version 2, return 0 .ENDIF ret GetPSP ENDP ;* GetMem - Gets total size of memory and determines the largest amount of ;* unallocated memory available. GetMem invokes DOS Function 48h (Allocate ;* Memory) to request an impossibly large memory block. DOS denies the re- ;* quest, but returns instead the size of the largest block available. This ;* is the amount that GetMem returns to the calling program. See the WinOpen ;* procedure for an example of calling Function 48h to allocate unused memory. ;* ;* Shows: BIOS Interrupt - 12h (Get Conventional Memory Size) ;* Instructions - push pop ret ;* ;* Params: None ;* ;* Return: Long integer, high word = total memory in kilobytes (KB) ;* low word = largest block of available memory (KB) GetMem PROC int 12h ; Get total memory in kilobytes push ax ; Save size of memory mov ah, 48h ; Request memory allocation mov bx, 0FFFFh ; Ensure request is denied for ; impossibly large block int 21h ; Get largest available block in BX mov ax, bx ; Copy to AX mov cl, 6 ; Convert paragraphs to kilobytes by shr ax, cl ; dividing by 64 pop dx ; Recover total in DX ret ; Return long integer DX:AX GetMem ENDP ;* VeriPrint - Checks if LPT1 (PRN) is available. ;* ;* Shows: BIOS Interrupt - 17h (Parallel Port Printer Driver) ;* ;* Params: None ;* ;* Return: Short integer, 1 for yes or 0 for no VeriPrint PROC mov ah, 2 ; Check printer status for sub dx, dx ; parallel printer (port 0) int 17h xchg dx, ax ; Put 0 (for error) in AX ; If all error bits are off and both operation bits are on, return 1 .IF !(dh & 00101001y) && (dh & 10010000y) inc ax ; Return 1 .ENDIF ret VeriPrint ENDP ;* IntToAsc - Converts integer to ASCII string. This procedure is useful ;* only for assembly language and is not intended to be callable by C. ;* ;* Shows: Instructions - aam xchg ;* ;* Entry: AX = integer (9999 max) ;* ;* Return: DX:AX = 4-digit ASCII number IntToAsc PROC cwd ; Zero DX register mov cx, 100 ; Divide AX by 100, yields div cx ; AX=quotient, DX=remainder aam ; Make digits unpacked BCD or ax, "00" ; Convert to ASCII xchg ax, dx ; Do same thing for DX aam or ax, "00" ret ; Return DX:AX = ASCII number IntToAsc ENDP ;* VeriAnsi - Checks for ANSI driver by writing ANSI sequence to report ;* cursor position. If report compares with position returned from ;* GetCurPos procedure, then ANSI driver is operating. ;* ;* Shows: DOS Functions - 06h (Direct Console I/O) ;* 0Ch (Flush Input Buffer and then Input) ;* ;* Params: None ;* ;* Return: Short integer, 1 for yes or 0 for no .DATA PUBLIC report report DB ESCAPE, "[6n$" ; ANSI Report Cursor sequence .CODE VeriAnsi PROC ; Get cursor position from BIOS INVOKE GetCurPos mov cx, ax ; Save it in CX mov dx, OFFSET report ; ANSI string to get position mov ah, 9 ; Request DOS String Output int 21h ; Write ANSI escape sequence mov ah, 6 ; Skip Esc character in mov dl, 0FFh ; keyboard buffer int 21h jz e_exit ; If no key, ANSI not loaded mov ah, 6 ; Skip '[' character int 21h jz e_exit ; If no key, ANSI not loaded mov ah, 6 ; Get 1st digit of cursor row int 21h jz e_exit ; If no key, ANSI not loaded mov bh, al ; Store in BH mov ah, 6 ; Get 2nd digit of cursor row int 21h jz e_exit ; If no key, ANSI not loaded mov bl, al ; Store in BL mov al, ch ; Get original row # in AL cbw ; AX = row # from GetCurPos inc ax ; Add 1 to it call IntToAsc ; Make ASCII digits cmp ax, bx ; ANSI and BIOS reports match? jne e_exit ; No? Then ANSI not loaded mov ax, 0C06h ; Flush remaining ANSI keys mov dl, 0FFh ; from buffer int 21h mov ax, 1 ; Set 1 for true jmp exit ; and exit e_exit: sub ax, ax ; Set 0 return code if no exit: ret ; ANSI driver installed VeriAnsi ENDP ;* VeriCop - Checks for coprocessor. ;* ;* Shows: BIOS Interrupt - 11h (Get Equipment Configuration) ;* ;* Params: None ;* ;* Return: Short integer, 1 for yes or 0 for no VeriCop PROC int 11h ; Check peripherals test al, 2 ; Coprocessor? mov ax, 0 ; Assume no, don't alter flags .IF !zero? inc ax ; Set to 1 .ENDIF ret VeriCop ENDP ;* SetLineMode - Sets line mode for EGA or VGA. ;* ;* Shows: BIOS Interrupt - 10h, Function 11h (Character Generator Interface) ;* 10h, Function 12h (Video Subsystem Configuration) ;* ;* Uses: vconfig - Video configuration structure (initialized ;* by calling the GetVidConfig procedure) ;* ;* Params: Line - Requested line mode (25, 43, or 50) ;* ;* Return: Short integer with error code ;* 0 if successful ;* 1 if error SetLineMode PROC, Line:WORD .IF vconfig.adapter >= EGA ; If EGA or VGA: mov ax, Line ; Check for valid parameter cmp al, 25 je line25 cmp al, 43 je line43 cmp al, 50 je line50 jmp e_exit ; If not 25, 43, or 50, exit w/ error line25: mov al, 11h ; Set for EGA 25-line mode cmp vconfig.adapter, EGA ; EGA? je linemode ; Yes? Continue mov ax, 1202h ; No? Function 12h for VGA mov bl, 30h ; AL = 2 for 400 scan lines int 10h ; Reset to 400 scan lines mov ax, 0003 ; Reset mode (Function 0) int 10h ; to mode 3 (80-col text) mov al, 14h ; Request 8x16 char matrix jmp linemode line43: mov al, 12h ; Set for EGA 43-line mode cmp vconfig.adapter, EGA ; EGA? je linemode ; Yes? Continue mov ax, 1201h ; No? Function 12h for VGA mov bl, 30h ; AL = 1 for 350 scan lines int 10h ; Reset to 350 scan lines mov ax, 0003 ; Reset mode (Function 0) int 10h ; to mode 3 (80-col text) mov al, 12h ; Request 8x8 character matrix jmp linemode line50: cmp vconfig.adapter, VGA ; VGA? jne e_exit ; No? Exit with error mov ax, 1202h ; Yes? Function 12h mov bl, 30h ; AL = 2 for 400 scan lines int 10h ; Reset to 400 scan lines mov ax, 0003 ; Reset mode (Function 0) int 10h ; to mode 3 (80-col text) mov al, 12h ; Request 8x8 character matrix linemode: sub bl, bl ; Use table 0 mov ah, 11h ; Request Function 11h int 10h ; Set new line mode mov ah, 12h ; Select alternate print mov bl, 20h ; screen for EGA and VGA int 10h cmp vconfig.adapter, VGA ; VGA? je exit ; Yes? Then exit cmp Line, 12h ; If EGA 43-line mode, set je port ; cursor through port to ; avoid cursor emulation bug ; Set normal cursor size, pass top and bottom scan lines INVOKE SetCurSize, 6, 7 jmp exit port: mov dx, 03D4h ; Video controller address mov ax, 060Ah ; Set AH = 06h (cursor start) ; AL = 0Ah (register #) out dx, ax ; Update port mov ax, 000Bh ; Set AH = 00h (cursor end) ; AL = 0Bh (register #) out dx, ax ; Update port jmp exit ; Normal exit .ENDIF ; EGA or VGA e_exit: mov ax, 1 ; Set error code jmp exit2 exit: sub ax, ax ; Clear error code exit2: ret SetLineMode ENDP ;* Pause - Waits for specified number of clocks to elapse, then returns. ;* ;* Shows: BIOS Interrupt - 1Ah, Function 0 (Real-Time Clock Driver) ;* Operators - LOCAL [] ;* ;* Params: Duration - Desired duration in clocks, where ;* 18 clocks = approx 1 second ;* ;* Return: None Pause PROC, Duration:WORD LOCAL tick:DWORD sub ah, ah int 1Ah ; Get Clock Count in CX:DX add dx, Duration ; Add pause time to it adc cx, 0 mov WORD PTR tick[0], dx ; Result is target time; mov WORD PTR tick[2], cx ; keep in local variable .REPEAT int 1Ah ; Poll clock until target time .UNTIL (dx >= WORD PTR tick[0]) || (cx >= WORD PTR fileinfo.time[2]) ret Pause ENDP ;* Sound - Sounds speaker with specified frequency and duration. ;* ;* Shows: Instructions - in out ;* ;* Params: Freq - Desired frequency of sound in hertz ;* Duration - Desired duration in clocks, where ;* 18 clocks = approx 1 second ;* ;* Return: None Sound PROC, Freq:WORD, Duration:WORD mov al, 0B6h ; Initialize channel 2 of out 43h, al ; timer chip mov dx, 12h ; Divide 1,193,182 hertz mov ax, 34DEh ; (clock frequency) by div Freq ; desired frequency ; Result is timer clock count out 42h, al ; Low byte of count to timer mov al, ah out 42h, al ; High byte of count to timer in al, 61h ; Read value from port 61h or al, 3 ; Set first two bits out 61h, al ; Turn speaker on ; Pause, pass duration of delay INVOKE Pause, Duration in al, 61h ; Get port value xor al, 3 ; Kill bits 0-1 to turn out 61h, al ; speaker off ret Sound ENDP ;* WriteTTY - Displays ASCIIZ string at cursor position, in either text ;* or graphics mode. ;* ;* Shows: BIOS Interrupt - 10h, Function 0Eh (Write Character in TTY Mode) ;* ;* Uses: vconfig - Video configuration structure (initialized ;* by calling the GetVidConfig procedure) ;* ;* Params: Sptr - Pointer to ASCIIZ string ;* icolor - Color index (for graphics mode only) ;* ;* Return: None WriteTTY PROC USES ds si, Sptr:PBYTE, icolor:WORD mov bx, icolor ; BL = color index mov bh, vconfig.dpage ; BH = current display page LoadPtr ds, si, Sptr mov cx, -1 ; Set loop counter to maximum mov ah, 14 ; Function 14 .REPEAT lodsb ; Get character from string .BREAK .IF al == 0 ; Exit if NULL string terminator int 10h ; No? Display, advance cursor .UNTILCXZ ret WriteTTY ENDP ;* Colors - Alters screen colors within a specified area by using bit ;* or move operations on display attribute bytes in video memory. ;* ;* Shows: Instructions - not rol ror and xor or ;* ;* Params: Logic - Code number, 0 = NOT 2 = ROR 4 = XOR 6 = MOV ;* 1 = ROL 3 = AND 5 = OR ;* Attr - Attribute mask ;* Row1 - Row at top of window ;* Col1 - Column at left edge of window ;* Row2 - Row at bottom of window ;* Col2 - Column at right edge of window ;* ;* Return: None Colors PROC USES ds si, Logic:WORD, Attr:WORD, Row1:WORD, Col1:WORD, Row2:WORD, Col2:WORD GetVidOffset Row1, Col1 ; Get offset in video segment inc ax mov si, ax ; SI = offset for 1st attr byte mov bx, Row2 sub bx, Row1 inc bx ; BX = number of window rows mov cx, Col2 sub cx, Col1 inc cx ; CX = number of columns mov ds, vconfig.sgmnt ; DS = video segment mov ax, Attr ; AL = mask for and, xor, and or .REPEAT push si ; Save ptr to start of line push cx ; and number of columns ; Disable CGA video prior to memory access to avoid screen snow. (See the ; WinOpen and StrWrite procedures for further discussions on CGA snow.) .IF vconfig.adapter == CGA ; If CGA adapter: INVOKE DisableCga ; Yes? Disable video .ENDIF cmp Logic, 1 ; Rotate left? jl c_not ; If less, do NOT je c_rol ; If equal, do ROL cmp Logic, 3 ; And? jl c_ror ; If less, do ROR je c_and ; If equal, do AND cmp Logic, 5 ; Or? jl c_xor ; If less, do XOR je c_or ; If equal, do OR c_mov: mov BYTE PTR [si], al ; MOV attr parameter add si, 2 ; into attribute byte loop c_mov jmp c_done c_or: or BYTE PTR [si], al ; OR with attr parameter add si, 2 loop c_or jmp c_done c_xor: xor BYTE PTR [si], al ; XOR with attr parameter add si, 2 loop c_xor jmp c_done c_and: and BYTE PTR [si], al ; AND with attr parameter add si, 2 loop c_and jmp c_done c_ror: ror BYTE PTR [si], 1 ; Rotate right 1 bit add si, 2 loop c_ror jmp c_done c_rol: rol BYTE PTR [si], 1 ; Rotate left 1 bit add si, 2 loop c_rol jmp c_done c_not: not BYTE PTR [si] ; Flip bits add si, 2 loop c_not c_done: .IF vconfig.adapter == CGA ; If CGA, INVOKE EnableCga ; reenable CGA video .ENDIF pop cx ; Recover number of columns pop si ; Recover offset for start of line add si, 160 ; Point to start of next line dec bx ; Decrement row counter .UNTIL zero? ; Loop while rows remain ret Colors ENDP ;* Exec - Executes a child process. Exec handles the usual chores associated ;* with spawning a process: (1) parsing the command line tail and loading the ;* FCBs with the first two arguments; (2) setting and restoring the vectors ;* for Interrupts 1Bh, 23h, and 24h; and (3) querying DOS for the child's ;* return code. ;* ;* Shows: DOS Functions - 29h (Parse Filename) ;* 25h (Set Interrupt Vector) ;* 35h (Get Interrupt Vector) ;* 4Bh (Execute Program) ;* 4Dh (Get Return Code) ;* ;* Params: Spec - Pointer to ASCIIZ specification for program file ;* (must include .COM or .EXE extension) ;* Block - Pointer to parameter block structure ;* CtrBrk - Pointer to new CTRL+BREAK (Interrupt 1Bh) handler ;* CtrlC - Pointer to new CTRL+C (Interrupt 23h) handler ;* Criterr - Pointer to new Critical Error (Interrupt 24h) handler ;* ;* Return: Short integer with child return code, or -1 for EXEC error Exec PROC USES ds si di, Spec:PBYTE, Block:PPARMBLK, CtrBrk:PTR FAR, CtrlC:PTR FAR, Criterr:PTR FAR Vector 1Bh, Old1Bh, CtrBrk ; Save, replace Int 1Bh vector Vector 23h, Old23h, CtrlC ; Save, replace Int 23h vector Vector 24h, Old24h, Criterr ; Save, replace Int 24h vector LoadPtr ds, bx, Block ; Point DS:BX to parameter block push ds ; Save segment address les di, (PARMBLK PTR [bx]).fcb1 ; Point ES:DI to first FCB lds si, (PARMBLK PTR [bx]).taddr ; Point DS:SI to command-line ; tail inc si ; Skip over count byte mov ax, 2901h ; Set AH to request Function 29h ; AL = flag to skip leading blanks int 21h ; Parse command-line into first FCB pop es ; Recover seg addr of parameter block les di, (PARMBLK PTR es:[bx]).fcb2 ; Point ES:DI to second FCB mov ax, 2901h ; Request DOS Function #29h again int 21h ; Parse command-line into second FCB push bp ; Save only important register mov WORD PTR cs:OldStk[0], sp mov WORD PTR cs:OldStk[2], ss LoadPtr es, bx, Block ; ES:BX points to param block LoadPtr ds, dx, Spec ; DS:DX points to path spec mov ax, 4B00h ; AH = DOS Function 4Bh ; AL = 0 for load and execute int 21h ; Execute Program mov sp, WORD PTR cs:OldStk[0] ; Reset stack pointers mov ss, WORD PTR cs:OldStk[2] pop bp ; Recover saved register ; Restore vectors for Interrupts 1Bh, 23h, and 24h. mov ax, 251Bh ; AH = DOS Function 25h ; AL = interrupt number lds dx, cs:Old1Bh ; DS:DX = original vector int 21h ; Set Interrupt 1Bh Vector mov al, 23h ; AL = interrupt number lds dx, cs:Old23h ; DS:DX = original vector int 21h ; Set Interrupt 23h Vector mov al, 24h ; AL = interrupt number lds dx, cs:Old24h ; DS:DX = original vector int 21h ; Set Interrupt 24h Vector mov ax, -1 ; Set error code .IF !carry? ; If no EXEC error: mov ah, 4Dh ; Request child's code int 21h ; Get Return Code sub ah, ah ; Make short integer .ENDIF ret Old1Bh FPVOID ? ; Keep vectors for Interrupts Old23h FPVOID ? ; 1Bh, 23h, and 24h in code Old24h FPVOID ? ; segment, but nonexecutable OldStk FPVOID ? ; Keep stack pointer Exec ENDP ;* BinToHex - Converts binary word to 6-byte hexadecimal number in ;* ASCIIZ string. String is right justified and includes "h" radix. ;* ;* Shows: Instruction - xlat ;* ;* Params: Num - Number to convert to hex string ;* Sptr - Pointer to 6-byte string ;* ;* Return: None .DATA hex BYTE "0123456789ABCDEF" ; String of hex numbers .CODE BinToHex PROC USES di, Num:WORD, Sptr:PBYTE LoadPtr es, di, Sptr ; Point ES:DI to 6-byte string mov bx, OFFSET hex ; Point DS:BX to hex numbers mov ax, Num ; Number in AX mov cx, 2 ; Loop twice for two bytes .REPEAT xchg ah, al ; Switch bytes push ax ; Save number shr al, 1 ; Shift high nibble to low shr al, 1 shr al, 1 shr al, 1 xlat ; Get equivalent ASCII number in AL stosb ; Copy to 6-byte string, increment DI pop ax ; Recover number push ax ; Save it again and al, 00001111y ; Mask out high nibble xlat ; Get equivalent ASCII number in AL stosb ; Copy to 6-byte string, increment DI pop ax ; Recover number .UNTILCXZ ; Do next byte mov ax, 'h' ; Put null, 'h' radix in AX stosw ; Copy to last two bytes in string ret BinToHex ENDP ;* NewBlockSize - Adjusts size of allocated memory block. ;* ;* Shows: DOS Function - 4Ah (Resize Memory Block) ;* ;* Params: Adr - Segment address of block ;* Resize - Requested block size in paragraphs ;* ;* Return: Short integer error code ;* 0 if successful ;* 1 if error NewBlockSize PROC, Adr:WORD, Resize:WORD mov ax, Adr ; Get block address mov es, ax ; Point ES to block mov bx, Resize ; New block size mov ah, 4Ah ; Function number int 21h ; Resize Memory Block ret NewBlockSize ENDP ;* Initialize - Initializes global variables _psp and _env, which are defined ;* in the DEMO.INC include file. If used with a DOS version less than 3.0, ;* this procedure will not produce valid results unless it is called before ;* changing the ES register. This is because at program entry ES points to ;* the Program Segment Prefix (PSP). ;* ;* Params: None ;* ;* Return: None Initialize PROC INVOKE GetPSP ; Get segment address of PSP .IF ax == 0 ; If less than DOS 3.0, mov es, ax ; reload ES with PSP address .ENDIF mov _psp, es ; Initialize variable with PSP address mov ax, es:[2Ch] ; Get environment seg from PSP mov _env, ax ; Store it ret Initialize ENDP END