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Assembly Source File | 1987-09-14 | 93KB | 1,899 lines

page 60,132 ;CARDFILE.COM for the IBM Personal Computer - 1987 by Jeff Prosise ; bios_data segment at 40h rs232_base dw 4 dup (?) ;UART base addresses org 4Ah crt_cols dw ? ;number of display columns org 4Eh crt_start dw ? ;video page offset address org 63h addr_6845 dw ? ;CRTC base address org 87h infobyte label word ega_info db ? ;EGA info byte bios_data ends ; code segment para public 'code' assume cs:code org 100h begin: jmp init1 ;goto initialization code ; program db "Cardfile 1.0 " copyright db "(c) 1987 Ziff Communications Co.",13,10 db "Hotkey is ALT-RIGHT SHIFT$",1Ah author db "Jeff Prosise" ; dos_segment dw ? ;segment of internal DOS flags indos_offset dw ? ;offset of INDOS flag errflag_offset dw ? ;offset of critical error flag program_status db 0 ;popup status flag_10h db 0 ;status of interrupt 10h flag_13h db 0 ;status of interrupt 13h request_flag db 0 ;status of processing request ss_register dw ? ;SS register storage sp_register dw ? ;SP register storage oldpsp dw ? ;PSP segment storage ; maxrec db 255 ;maximum number of records recptr db 1 ;current record number numrec db 0 ;number of records adapter db ? ;0=MDA, 1=CGA, 2=EGA video_segment dw ? ;video segment address border_attr db ? ;window border attribute text_attr db ? ;window text attribute menu_attr db ? ;menu line attribute record_attr db ? ;record display attribute video_page db ? ;current video page cursor_mode dw ? ;cursor shape cursor_pos dw ? ;cursor position cursor_addr dw ? ;cursor CRTC address new_cursor dw ? ;Cardfile cursor shape dos_version db ? ;DOS version number slotno db ? ;record position reload db ? ;reload data file flag zflag db ? ;critical error flag change status fileflag db 0 ;filespec validity indicator record_length db 192 ;record length in bytes ; comport dw 0 ;COM1 initstr db 10000011b ;1200 baud, N81 data format dialstr db "ATDT",0 ;Hayes Smartmodem dial string hangupstr db "ATH0",13,0 ;Hayes Smartmodem hangup string ; jump_table dw offset create ;vector dispatch table dw offset edit dw offset delete dw offset search dw offset save dw offset dial ; titles db 32,"Name",32,32,"Addr",14 dup (32),"Phone",32,"Note",32 menuline1 db "F1-New F2-Ed F3-Del F4-Sch F5-Sv F6-Dial",0 menuline2 db "Press ENTER to delete, ESC to abort",0 menuline3 db "Press F1 to validate new entry",0 menuline4 db "Find:",0 menuline5 db "Press ENTER to continue, ESC to end",0 menuline6 db "Search key not found. Press ESC",0 menuline7 db "No room for additional records",0 menuline8 db "Disk full",0 menuline9 db "Press F1 to validate changes",0 menuline10 db "Pick up phone and press spacebar",0 menuline11 db "Error saving file",0 menuline12 db "Modem not ready",0 menuline13 db "File:",0 ; timer_int label dword ;old interrupt 8 vector old8h dw 2 dup (?) keyboard_int label dword ;old interrupt 9 vector old9h dw 2 dup (?) video_int label dword ;old interrupt 10h vector old10h dw 2 dup (?) bdisk_int label dword ;old interrupt 13h vector old13h dw 2 dup (?) bp_int label dword ;old interrupt 28h vector old28h dw 2 dup (?) ; old1Bh_segment dw ? ;old interrupt 1Bh segment old1Bh_offset dw ? ;old interrupt 1Bh offset old23h_segment dw ? ;old interrupt 23h segment old23h_offset dw ? ;old interrupt 23h offset old24h_segment dw ? ;old interrupt 24h segment old24h_offset dw ? ;old interrupt 24h offset ; color_attr db 0,0B8h,1Fh,6Eh,6Eh,6Fh mono_attr db 0,0B0h,70h,07h,07h,07h enable_values db 2Ch,28h,2Dh,29h,2Ah,2Eh,1Eh key_table db "QWERTYUIOP",0,0,0,0 db "ASDFGHJKL",0,0,0,0,0 db "ZXCVBNM" ; ;------------------------------------------------------------------------------ ;Execution comes here thru interrupt 9 every time a key is pressed or released. ;------------------------------------------------------------------------------ keyboard proc near sti ;set interrupt enable flag pushf ;push flags to simulate INT call keyboard_int ;call keyboard handling routine push ax ;save AX mov ah,2 ;get keyboard shift status int 16h and al,0Fh ;mask off upper 4 bits cmp al,9 ;Alt/Rt-Shift pressed? pop ax ;restore AX jne kb_exit ;no, then exit cmp program_status,0 ;popup routine already active? jne kb_exit ;yes, then ignore keypress mov request_flag,18 ;set request flag kb_exit: iret keyboard endp ; ;------------------------------------------------------------------------------ ;Interrupt 8 handling routine. ;------------------------------------------------------------------------------ timer proc near pushf ;call BIOS routine call timer_int cmp request_flag,0 ;flag set? je timer_exit ;no, then exit cmp flag_10h,0 ;video flag set? jne dectime ;yes, then exit cmp flag_13h,0 ;disk flag set? jne dectime ;yes, then exit push es ;save ES and DI push di mov es,dos_segment ;check INDOS flag mov di,indos_offset cmp byte ptr es:[di],0 jne poptime ;exit if it's set mov di,errflag_offset ;check critical error flag cmp byte ptr es:[di],0 jne poptime ;exit if it's set pop di ;restore registers pop es mov request_flag,0 ;zero request flag call main ;call body of program timer_exit: iret poptime: pop di ;clean up the stack pop es dectime: dec request_flag ;decrement request flag iret timer endp ; ;------------------------------------------------------------------------------ ;Interrupt 10h handling routine. ;------------------------------------------------------------------------------ video proc near pushf ;push flags onto stack inc flag_10h ;increment flag call video_int ;call BIOS routine dec flag_10h ;decrement flag iret video endp ; ;------------------------------------------------------------------------------ ;Interrupt 13h handling routine. ;------------------------------------------------------------------------------ bdisk proc far pushf ;push flags onto stack inc flag_13h ;set 'busy' flag call bdisk_int ;call BIOS routine pushf ;save output flags dec flag_13h ;clear flag popf ;restore output flags ret 2 ;exit without destroying flags bdisk endp ; ;------------------------------------------------------------------------------ ;Interrupt 28h handling routine. ;------------------------------------------------------------------------------ backproc proc near pushf ;call original routine call bp_int cmp request_flag,0 ;request flag clear? je bp_exit ;yes, then exit cmp flag_10h,0 ;video flag set? jne bp_exit ;yes, then exit cmp flag_13h,0 ;disk flag set? jne bp_exit ;yes, then exit push es ;save ES and DI push di mov es,dos_segment ;check critical error flag mov di,errflag_offset cmp byte ptr es:[di],0 pop di ;clean up the stack pop es jne bp_exit mov request_flag,0 ;clear request flag call main ;call main routine bp_exit: iret ;done - exit backproc endp ; ;------------------------------------------------------------------------------ ;Interrupt 24h handling routine (DOS 3.X only). ;------------------------------------------------------------------------------ ioerr proc near mov al,3 ;fail the call in progress ioexit: iret ;give control back to DOS ioerr endp ; ;------------------------------------------------------------------------------ ;MAIN is the routine called to pop up and manipulate the CardFile window. ;------------------------------------------------------------------------------ main proc near mov program_status,1 ;set program active flag cli ;make sure interrupts are off mov ss_register,ss ;save stack registers mov sp_register,sp push cs ;switch to internal stack pop ss mov sp,offset filespec sti ;enable interrupts push ax ;save other registers push bx push cx push dx push si push di push ds push es push bp mov ah,15 ;get video mode and page int 10h cmp al,3 ;mode 0, 1, 2, or 3? jbe main1 ;yes, then continue cmp al,7 ;mode 7? je main1 ;yes, then continue ; ;Restore registers and stack before exit. ; exit: pop bp ;restore registers and exit pop es pop ds pop di pop si pop dx pop cx pop bx pop ax cli ;interrupts off mov ss,ss_register ;switch to original stack mov sp,sp_register sti ;interrupts on mov program_status,0 ;clear status flag ret ; ;Set DS and ES segment registers. ; main1: push cs ;set DS to code segment pop ds assume ds:code mov ax,bios_data ;point ES to BIOS data mov es,ax assume es:bios_data cmp crt_cols,80 ;at least 80 columns displayed? jb exit ;no, then exit ; ;Save needed video parameters. ; mov video_page,bh ;active video page mov ah,3 ;get cursor mode and location int 10h mov cursor_mode,cx mov cursor_pos,dx mov dx,addr_6845 ;get CRTC base address push dx ;save it for later mov al,14 ;specify register number out dx,al inc dx ;point DX to data port in al,dx ;read high byte of address mov ah,al ;save it dec dx ;back to index register mov al,15 ;specify register number out dx,al inc dx ;back to data port in al,dx ;read low byte of address mov cursor_addr,ax ;save cursor address ; ;Determine whether an EGA is present and active in the system. ; mov ah,12h ;see if EGA is present mov bl,10h int 10h cmp bl,10h ;did BL return unchanged? je main2 ;yes, then there's no EGA here test ega_info,8 ;is the EGA currently active? jnz main2 ;no, then branch mov adapter,2 ;set ADAPTER for EGA push bx ;save BX mov ax,1130h ;get number of scan lines per char int 10h dec cl ;form cursor definition in CX mov ch,cl sub ch,2 mov new_cursor,cx ;save cursor definition mov si,offset color_attr ;point SI to color parms pop bx ;retrieve BX or bh,bh ;EGA attached to color monitor? je main4 ;yes, then branch mov si,offset mono_attr ;no, then point SI to mono parms jmp short main4 ; ;Determine whether the active video adapter is a CGA or an MDA. ; main2: test addr_6845,40h ;is bit 6 of the CRTC address set? jz main3 ;no, then it's monochrome mov adapter,1 ;set ADAPTER for a CGA mov new_cursor,0607h ;define cursor shape mov si,offset color_attr ;point SI to color parms jmp short main4 main3: mov adapter,0 ;set ADAPTER for an MDA mov new_cursor,0B0Ch ;define monochrome cursor mov si,offset mono_attr ;point SI to mono parms ; ;Set video parameters for color or monochrome. ; main4: push cs ;set ES to the code segment pop es assume es:nothing mov di,offset video_segment ;point DI to destination mov cx,3 ;3 words to move cld ;clear DF rep movsw ;transfer the values ; ;Save the current active PSP address and activate this PSP. ; push es ;save ES mov zflag,0 ;clear flag cmp dos_version,2 ;DOS version 2.X? jne main5 mov es,dos_segment ;point ES:DI to INDOS mov di,indos_offset cmp byte ptr es:[di],0 ;INDOS clear? je main5 ;yes, then branch mov di,errflag_offset ;point ES:DI to error flag cmp byte ptr es:[di],0 ;critical error flag clear? jne main5 ;no, then branch mov byte ptr es:[di],1 ;set critical error flag manually mov zflag,1 ;set change flag main5: mov ah,51h ;get current PSP segment int 21h mov oldpsp,bx ;save it mov ah,50h ;make this the active PSP push cs pop bx int 21h cmp zflag,0 ;ZFLAG clear? je main6 ;yes, then branch mov di,errflag_offset ;point ES:DI to error flag mov byte ptr es:[di],0 ;restore error flag value main6: pop es ;restore ES ; ;Reset the interrupt 1Bh, 23h, and 24h vectors and open the CardFile window. ; call ioset ;reset interrupt vectors cmp adapter,1 ;disable CGA video jne main7 call disable_cga main7: call save_screen ;save memory to be overwritten call make_screen ;open the CardFile window cmp adapter,1 ;enable CGA video jne main8 call enable_cga main8: mov ah,1 ;hide the cursor mov ch,20h int 10h cmp numrec,0 ;any records in memory? je main10 ;no, then branch call show_record ;display current record ; ;Wait for a keystroke and exit when ESC is pressed. ; main10: call getkey ;wait for a keypress or al,al ;extended code entered? je main12 ;yes, then branch cmp al,13 ;ENTER pressed? jne main11 ;no, then branch around cmp numrec,2 ;at least 2 records? jb main10 ;no, then ignore keypress jmp short main20 ;yes, then do a PgDn main11: cmp al,27 ;ESC pressed? jne main10 ;no, then ignore keypress jmp short escape ;yes, then close window and exit ; ;An extended code was entered. Check for an Alt-character key combination. ; main12: cmp ah,16 ;scan code < 16 (Alt-Q)? jb main10 ;yes, then ignore it cmp ah,50 ;scan code > 50 (Alt-M)? ja main13 ;yes, then branch and continue call qsearch ;do quick search jmp main10 ;return for another keypress ; ;Check for a press of any function key F1 through F6. ; main13: cmp ah,59 ;scan code < 59 (F1)? jb main10 ;yes, then ignore it cmp ah,64 ;scan code > 64 (F6)? ja main14 ;yes, then branch and continue sub ah,59 ;normalize scan code mov bl,ah ;transfer result xor bh,bh ;byte to word in BX shl bx,1 ;double index in BX call word ptr cs:[offset jump_table+bx] ;call routine jmp main10 ;return ; ;Check for Home, End, PgUp, and PgDn. ; main14: cmp numrec,2 ;are there at least 2 records? jb main10 ;no, then ignore keypress cmp ah,71 ;Home key? jne main16 ;no, then branch mov recptr,1 ;set pointer to first record main15: call show_record ;display record jmp main10 ;return main16: cmp ah,79 ;End key? jne main18 ;no, then branch main17: mov al,numrec ;get number of records mov recptr,al ;set pointer to last record jmp main15 ;display record main18: cmp ah,73 ;PgUp key? jne main19 ;no, then branch dec recptr ;adjust pointer cmp recptr,0 ;wrap around if necessary jne main15 jmp main17 main19: cmp ah,81 ;PgDn key? jne main10 ;no, then ignore keypress main20: mov al,numrec ;presently showing last record? cmp al,recptr je main21 ;yes, then branch inc recptr ;no, then advance pointer jmp main15 ;display record main21: mov recptr,1 ;set pointer to first record jmp main15 ;display record ; ;Restore interrupt vectors and former active PSP. ; escape: mov ah,50h ;restore active PSP label mov bx,oldpsp int 21h call ioreset ;restore interrupt vectors ; ;Close the Cardfile window in preparation for exit. ; cmp adapter,1 ;disable CGA video jne esc1 call disable_cga esc1: call restore_screen ;restore screen contents cmp adapter,1 ;enable CGA video jne esc2 call enable_cga ; ;Restore the cursor's former position in the BIOS data area and the CRTC. ; esc2: mov ah,2 ;set cursor position thru BIOS mov bh,video_page mov dx,cursor_pos int 10h pop dx ;recover CRTC base address mov cx,cursor_addr ;restore cursor address mov al,14 ;CRTC register number out dx,al inc dx mov al,ch out dx,al ;write high byte of address dec dx mov al,15 ;CRTC register number out dx,al inc dx mov al,cl out dx,al ;write low byte ; ;Display the cursor, bypassing EGA cursor emulation logic, and exit. ; cmp adapter,2 ;EGA on board? jne esc3 ;no, then branch call show_cursor ;retain current shape jmp exit esc3: mov ah,1 ;restore cursor shape mov cx,cursor_mode int 10h jmp exit ;exit main endp ; ;------------------------------------------------------------------------------ ;SAVE_SCREEN saves the contents of the screen that underlie the window. ;------------------------------------------------------------------------------ linesum dw ? video_address dw ? ; save_screen proc near push ds ;save DS mov ax,bios_data ;point it to BIOS data area mov ds,ax assume ds:bios_data mov ax,crt_cols ;get number of display columns mov linesum,ax ;calculate distance from end of sub linesum,44 ; one line to start of next shl linesum,1 mov bl,6 ;calculate starting address mul bl ;result in AX shl ax,1 ;double result for attr bytes add ax,36 ;add line offset mov si,ax ;transfer to SI add si,crt_start ;add page offset mov video_address,si ;save offset address mov ds,video_segment ;then set DS to the video segment mov di,offset screen_buffer ;point DI to storage buffer mov cx,10 ;10 lines to save save1: push cx ;save line count mov cx,44 ;44 characters per line rep movsw ;transfer one line to storage pop cx ;retrieve line count add si,linesum ;point SI to next video line loop save1 ;loop until all lines are saved pop ds ;restore DS assume ds:code ret ;exit save_screen endp ; ;------------------------------------------------------------------------------ ;RESTORE_SCREEN writes the stored screen image to video memory. ;------------------------------------------------------------------------------ restore_screen proc near push es ;save ES register value mov di,video_address ;point DI to starting video offset mov es,video_segment ;point ES to video memory mov si,offset screen_buffer ;point DS:SI to screen image mov cx,10 ;10 lines to restore restore1: push cx ;save line count mov cx,44 ;44 characters per line rep movsw ;restore one line pop cx ;retrieve line count add di,linesum ;set DI to next video line loop restore1 ;loop until done pop es ;restore ES ret restore_screen endp ; ;------------------------------------------------------------------------------ ;MAKE_SCREEN writes an image of the CardFile window to video memory. ;------------------------------------------------------------------------------ make_screen proc near push es ;save ES mov es,video_segment ;point ES:DI to video memory mov di,video_address mov al,218 ;line no. 1 mov ah,border_attr stosw mov al,196 mov cx,42 rep stosw mov al,191 stosw add di,linesum mov si,offset titles ;lines 2 thru 7 mov cx,6 ;6 lines make1: push cx call formline add di,linesum pop cx loop make1 mov al,179 ;line no. 8 stosw push ax mov al,32 mov ah,text_attr stosw push ax mov al,196 mov cx,40 rep stosw pop ax stosw pop ax stosw add di,linesum stosw ;line no. 9 push ax mov al,32 mov ah,menu_attr stosw push ax mov si,offset menuline1 mov cx,40 make2: lodsb stosw loop make2 pop ax stosw pop ax stosw add di,linesum mov al,192 ;line no. 10 stosw mov al,196 mov cx,42 rep stosw mov al,217 stosw pop es ;restore ES ret make_screen endp ; ;------------------------------------------------------------------------------ ;FORMLINE is called by MAKE_SCREEN to help with the dirty work. ;------------------------------------------------------------------------------ formline proc near mov al,179 ;write border character mov ah,border_attr stosw push ax ;save it for later mov cx,6 ;do next 6 characters mov ah,text_attr form1: lodsb stosw loop form1 mov al,32 ;add 2 blanks stosw stosw mov ah,record_attr ;then add 34 blank characters mov cx,34 rep stosw pop ax ;finish with border character stosw ret formline endp ; ;------------------------------------------------------------------------------ ;QSEARCH pages to the record whose first character matches the Alt key pressed. ;------------------------------------------------------------------------------ qsearch proc near cmp numrec,2 ;at least 2 records to search? jb qs3 ;no, then exit mov al,ah ;transfer scan code to AL sub al,16 ;normalize it mov bx,offset key_table ;address table of equivalents xlat ;get corresponding ASCII code mov dl,al ;transfer it to DL mov cl,numrec ;get record count in CX xor ch,ch mov al,1 ;initialize record index qs1: push ax ;save index push cx ;save count call record_address ;get address of current record cmp [di],dl ;compare characters pop cx ;retrieve count and index pop ax jae qs2 ;end search inc al ;increment index loop qs1 ;loop back for next record dec al ;search exhausted qs2: cmp al,recptr ;record already showing? je qs3 ;yes, then exit mov recptr,al ;no, then change display call show_record qs3: ret qsearch endp ; ;------------------------------------------------------------------------------ ;SEARCH searches data for occurrence of a string input by the user. ;------------------------------------------------------------------------------ strlen db ? ;string length passes db ? ;number of search loops ; search proc near cmp numrec,0 ;any records to search? je search_exit ;no, then exit mov si,offset menuline4 ;prepare menu line for input call write_menu xor di,di ;read string from keyboard mov dx,0E1Ah mov cl,32 call readln or cl,cl ;anything entered? jne search1 ;yes, then continue search_exit: mov si,offset menuline1 ;restore menu line and exit call write_menu ret ; ;Set search parameters and begin the scan. ; search1: mov strlen,cl ;save string length mov ch,33 ;determine no. of passes per line sub ch,cl mov passes,ch ;save it mov al,recptr ;start search at current record mov cl,numrec ;set max search length xor ch,ch search2: push ax ;save record number push cx ;save record count call record_address ;get address of current record mov cx,6 ;6 lines per record search3: push cx ;save line count push di ;save line address mov cl,passes ;set number of passes per line xor ch,ch search4: push cx ;save pass count push di ;save search address within line mov cl,strlen ;number of bytes to compare xor ch,ch xor si,si ;point SI to input buffer search5: lodsb ;get a byte from the input buffer and al,0DFh ;capitalize it mov bl,es:[di] ;get a byte from the record and bl,0DFh ;capitalize it inc di ;advance pointer cmp al,bl ;are the two bytes identical? jne nextpos ;no, then try next position loop search5 ;yes, then try next byte ; ;A match was found. Clean up the stack and display the record. ; add sp,10 ;delete last 5 words PUSHed pop ax ;retrieve current record number push ax ;push it back onto the stack mov cl,numrec ;restart the record counter xor ch,ch inc cx push cx ;shove it onto the stack mov recptr,al ;set current record to this one call show_record ;display new record mov si,offset menuline5 ;display new menu line call write_menu searchkey: call getkey ;wait for a keypress cmp al,13 ;ENTER key? je nextrec ;yes, then continue search cmp al,27 ;ESC key? jne searchkey ;no, then ignore the keypress pop cx ;clean up the stack pop ax jmp search_exit ;exit ; ;Advance to the next position and continue the string search. ; nextpos: pop di ;retrieve address pop cx ;retrieve pass count inc di ;advance to next position on line loop search4 ;loop back for another try nextline: pop di ;retrieve line address pop cx ;retrieve line count add di,32 ;advance pointer to next line loop search3 ;loop back nextrec: pop cx ;retrieve record count pop ax ;retrieve current record number cmp al,numrec ;currently on last record? je reset ;yes, then wrap around inc al ;no, then advance record pointer jmp short next1 reset: mov al,1 ;reset record pointer next1: loop search2 ;reenter main loop ; ;All records were searched and no match was found. ; mov si,offset menuline6 ;print message call write_menu search6: call getkey ;wait for a press of ESC cmp al,27 jne search6 jmp search_exit ;exit search endp ; ;------------------------------------------------------------------------------ ;DIAL dials the phone number currently displayed. ;------------------------------------------------------------------------------ linectrl db ? ;Line Control Register value divlsb db ? ;baud rate divisor LSB divmsb db ? ;baud rate divisor MSB intreg db ? ;Interrupt Enable Register value ; dial proc near cmp numrec,0 ;any records in memory? jne dstart ;yes, then branch dial_exit: ret ;no, then exit ; ;Save the current state of the COM port. ; dstart: mov si,comport ;get UART base address shl si,1 push es ;save ES mov ax,bios_data ;then point it to BIOS data area mov es,ax assume es:bios_data mov dx,rs232_base[si] pop es ;restore ES assume es:nothing or dx,dx ;is this port installed? je dial_exit ;no, then exit add dx,3 ;point DX to Line Control Register push dx ;save the address in al,dx ;read LCR mov linectrl,al ;store value for later or al,80h ;set DLAB out dx,al sub dx,3 ;point DX to Divisor LSB Register in al,dx ;read it mov divlsb,al ;save it inc dx ;point DX to Divisor MSB Register in al,dx ;read it mov divmsb,al ;save it mov al,linectrl ;recover Line Control setting and al,07Fh ;clear the high bit add dx,2 ;point DX back to Line Control out dx,al ;clear DLAB sub dx,2 ;address Interrupt Enable Register in al,dx ;read it mov intreg,al ;and save it ; ;Initialize the COM port. ; mov ah,0 ;initialize COM port mov al,initstr ;baud rate and data format mov dx,comport ;COM port identifier int 14h ; ;Dial the phone number. ; mov si,offset dialstr ;point DS:SI to 'ATDT' string call sendcom ;output string to COM port test ah,80h ;was the string sent? jnz time_out ;no, then modem isn't ready mov al,recptr ;get address of current record call record_address mov si,di add si,128 ;point SI to 'Phone' line mov cx,32 ;32 characters to check dial1: lodsb ;get one character cmp al,"," ;is it a comma? je dial2 ;yes, then send it cmp al,"0" ;less than ASCII zero? jb dial3 ;yes, then ignore it cmp al,"9" ;greater than ASCII 9? ja dial3 ;yes, then ignore it dial2: mov ah,1 ;output byte to COM port int 14h test ah,80h ;was the byte successfully output? jnz time_out ;no, then modem isn't ready dial3: loop dial1 ;loop until line is finished mov ax,013Bh ;terminate with semicolon and CR int 14h mov ax,010Dh int 14h test ah,80h ;were the bytes transmitted? jz dial5 ;yes, then continue ; ;Display 'Modem not ready' message and wait for ESC to be pressed. ; time_out: mov si,offset menuline12 ;print message call write_menu dial4: call getkey ;wait for a press of ESC cmp al,27 jne dial4 jmp dial8 ; ;Wait for a press of the spacebar, then force the modem to hang up. ; dial5: mov si,offset menuline10 ;display 'Pick up phone...' call write_menu dial6: call getkey ;wait for a press of the spacebar cmp al,32 jne dial6 mov si,offset hangupstr ;point SI to 'ATH0' string mov dx,comport ;specify COM port call sendcom ;output it to the COM port mov cx,8000h ;I/O delay dial7: loop dial7 ; ;Restore the COM port to its original state and exit. ; dial8: pop dx ;retrieve UART address mov al,80h ;set DLAB out dx,al sub dx,3 ;point DX to Divisor LSB mov al,divlsb ;reset it out dx,al inc dx ;point DX to MSB mov al,divmsb ;reset it out dx,al add dx,2 ;point DX to Line Control xor al,al ;clear DLAB out dx,al sub dx,2 ;point DX to Interrupt Enable mov al,intreg ;restore it out dx,al add dx,2 ;restore Line Control Register mov al,linectrl out dx,al mov si,offset menuline1 ;restore menu line and exit call write_menu ret dial endp ; ;------------------------------------------------------------------------------ ;SENDCOM outputs an ASCIIZ string to the designated COM port. ;Entry: DS:SI - string address | Exit: AH bit 7 clear - string sent ; DX - 0 = COM1, 1 = COM2 | AH bit 7 set - time out ;------------------------------------------------------------------------------ sendcom proc near lodsb ;get a byte or al,al ;zero terminator? je comexit ;yes, then exit mov ah,1 ;output byte int 14h test ah,80h ;was byte transmitted? jz sendcom ;yes, loop back for more comexit: ret ;exit sendcom endp ; ;------------------------------------------------------------------------------ ;EDIT allows the current record to be edited. ;------------------------------------------------------------------------------ edit proc near cmp numrec,0 ;any records to edit? je edit1 ;no, then exit mov al,recptr ;get current record number call record_address ;get its address and position mov slotno,al ;save position push di ;save address call delete_record ;delete it pop di ;recover address push di ;save it again mov si,offset menuline9 ;address menu line text call edit_record ;allow it to be edited pop si ;place address in SI jc no_entry ;branch if entry now blank call find_position ;determine logical position mov bl,slotno ;retrieve physical position call insert_record ;insert record into the stack mov recptr,cl ;modify current record number edit1: ret ;exit no_entry: cmp numrec,0 ;any records left after deletion? je edit1 ;no, then we're done mov al,numrec ;get number of records cmp al,recptr ;RECPTR in range? jae edit2 ;yes, then branch dec recptr ;no, then modify it edit2: call show_record ;display new current record ret edit endp ; ;------------------------------------------------------------------------------ ;CREATE allows a new record to be created and inserted. ;------------------------------------------------------------------------------ create proc near mov al,numrec ;retrieve number of records cmp al,maxrec ;room for another record? jne create1 ;yes, then branch mov si,offset menuline7 ;no, then print error message call write_menu create0: call getkey ;wait for a press of ESC cmp al,27 jne create0 mov si,offset menuline1 ;restore menu line call write_menu ret ;exit create1: call clear_window ;clear the current display xor al,al ;zero AL call record_address ;get address of empty record slot mov slotno,al ;save position mov al,32 ;blank the record mov cx,192 rep stosb sub di,192 ;point DI back to start of record push di ;save address mov si,offset menuline3 ;set text address call edit_record ;allow record to be edited pop si ;get address in SI jc blank_entry ;branch if new entry is blank call find_position ;determine new record position mov bl,slotno ;retrieve its physical position call insert_record ;insert new record into stack mov recptr,cl ;point RECPTR to new record ret blank_entry: cmp numrec,0 ;any records? je blank1 ;no, then exit call show_record ;display current record blank1: ret create endp ; ;------------------------------------------------------------------------------ ;DELETE deletes the current record. ;------------------------------------------------------------------------------ delete proc near cmp numrec,0 ;any records to delete? je del_exit ;no, then exit mov si,offset menuline2 ;request verification call write_menu del1: call getkey ;get keyboard response cmp al,13 ;ENTER pressed? je del2 ;yes, then continue cmp al,27 ;ESC pressed? jne del1 ;no, then get another keypress del2: push ax ;save response mov si,offset menuline1 ;restore menu line call write_menu pop ax ;retrieve response cmp al,13 ;delete the record? jne del_exit ;no call delete_record ;delete current record cmp numrec,0 ;any records left? jne del3 ;yes, then branch call clear_window ;no, then clear display del_exit: ret ;exit del3: mov al,numrec ;get record count cmp al,recptr ;is RECPTR in range? jae del4 ;yes, then branch dec recptr ;no, then make sure it is del4: call show_record ;display new current record ret delete endp ; ;------------------------------------------------------------------------------ ;SAVE writes the data in memory to disk. ;------------------------------------------------------------------------------ save proc near cmp numrec,0 ;any records to save? jne fsave1 ;yes, then continue ret ;no, then exit fsave1: cmp fileflag,0 ;does a filespec exist? jne fsave2 ;yes, then branch ; ;Read a filespec input from the keyboard. ; getname: mov si,offset menuline13 ;print input prompt call write_menu xor di,di ;prepare for call to READLN mov dx,0E1Ah mov cl,34 call readln ;read the filespec or cl,cl ;anything entered? je save_exit ;no, then exit mov fileflag,1 ;set filespec indicator xor si,si ;copy filespec into buffer mov di,offset filespec xor ch,ch rep movsb mov byte ptr es:[di],0 ;zero last byte ; ;Open the file and write record data out to it. ; fsave2: mov dx,offset filespec ;point DX to filespec mov ah,3Ch ;open/create file xor cx,cx ;normal attributes int 21h jc getname ;get new filespec if open failed fsave3: mov bx,ax ;transfer file handle to BX mov ah,40h ;write NUMREC byte to file mov cx,1 mov dx,offset numrec int 21h jc save_error ;branch on error cmp ax,1 ;byte successfully written? jb diskfull ;no, then disk is full mov al,1 ;initialize record number mov cl,numrec ;get number of records to write xor ch,ch fsave4: push cx ;save count push ax ;save record number call record_address ;get address of current record mov dx,di ;transfer it to DX mov cx,192 ;192 bytes per record mov ah,40h ;write one record int 21h mov dx,ax ;transfer byte count to DX pop ax ;retrieve record number and count pop cx jc save_error ;branch on error cmp dx,192 ;entire record written? jb diskfull ;no, then disk is full inc al ;next record loop fsave4 ;loop until done closefile: mov ah,3Eh ;close file int 21h save_exit: mov si,offset menuline1 ;restore menu line call write_menu ret ;exit ; ;An error was encountered during the save. ; save_error: mov si,offset menuline11 ;print error message push bx ;save file handle call write_menu pop bx ;retrieve file handle error2: call getkey ;wait for a press of ESC cmp al,27 jne error2 jmp short closefile ;close file and resume ; ;No room left on the disk. ; diskfull: mov si,offset menuline8 ;print 'Disk full' message push bx ;save file handle call write_menu pop bx ;retrieve file handle full2: call getkey ;wait for a press of ESC cmp al,27 jne full2 jmp short closefile ;and exit save endp ; ;------------------------------------------------------------------------------ ;DISABLE_CGA and ENABLE_CGA disable and enable CGA video output. ;------------------------------------------------------------------------------ disable_cga proc near mov dx,3DAh ;address of Status Register disable1: in al,dx ;get status test al,8 ;vertical retrace active? je disable1 ;no, then wait sub dx,2 ;MSR address in DX mov al,25h ;value to disable video out dx,al ;disable video output ret disable_cga endp ; enable_cga proc near mov ah,15 ;get video mode int 10h mov bx,offset enable_values ;get value to enable display xlat ;value in AL mov dx,3D8h ;MSR address out dx,al ;enable video output ret enable_cga endp ; ;------------------------------------------------------------------------------ ;GETKEY waits for a keypress and returns the keycode in AX. ;Exit: AX - keycode ;------------------------------------------------------------------------------ getkey proc near mov ah,1 ;check keyboard buffer int 16h jne getkey1 ;jump if buffer contains a keycode int 28h ;no key pressed - issue int 28h jmp getkey ;loop back to try again getkey1: mov ah,0 ;get keycode from buffer int 16h ret ;exit with keycode in AX getkey endp ; ;------------------------------------------------------------------------------ ;INSERT_RECORD inserts a record into the stack. ;Entry: BL - slot number ; CL - index number ;------------------------------------------------------------------------------ insert_record proc near push cx ;save index number mov di,offset index_table ;point DI to index table mov al,cl ;get index number in AL for search mov cl,maxrec ;set counter xor ch,ch insert1: cmp [di],al ;index less than new index? jb insert2 ;yes, then branch inc byte ptr [di] ;increment index insert2: inc di ;advance DI to next index loop insert1 ;loop until all indexes examined pop cx ;retrieve new index number xor bh,bh ;byte to word in BX mov di,offset index_table ;point DI to index table mov [di+bx],cl ;deposit new index into table inc numrec ;increment record count by 1 ret insert_record endp ; ;------------------------------------------------------------------------------ ;DELETE_RECORD deletes the record indexed by RECPTR. ;------------------------------------------------------------------------------ delete_record proc near mov al,recptr ;search for current record slot mov di,offset index_table mov cl,maxrec xor ch,ch repne scasb dec di ;back to matching byte mov byte ptr [di],0 ;zero current index mov al,recptr ;get current record number mov di,offset index_table ;point DI to index table mov cl,maxrec ;set counter xor ch,ch delrec1: cmp [di],al ;index less than current index? jb delrec2 ;yes, then branch dec byte ptr [di] ;no, decrement index delrec2: inc di ;advance to next index loop delrec1 ;loop until all records examined dec numrec ;decrement record count by 1 ret delete_record endp ; ;------------------------------------------------------------------------------ ;EDIT_RECORD allows the record addressed by ES:DI to be edited. ;Entry: ES:DI - record address | Exit: CF clear - record valid ; DS:SI - menu line text string | CF set - record blank ;------------------------------------------------------------------------------ edit_record proc near push di ;save starting address call write_menu ;write new menu line mov bh,video_page ;set BH for video calls mov ah,2 ;set initial cursor position mov dx,071Bh int 10h call show_cursor ;display the cursor ; ;Wait for a keypress. ; editrec1: call getkey ;get a keypress or al,al ;extended code? jne editrec2 ;no, then branch jmp short extend ;goto extended code handler editrec2: cmp al,8 ;backspace key? je bspace cmp al,13 ;ENTER key? je enter cmp al,32 ;ASCII code less than 32? jb editrec1 ;yes, then ignore it ; ;Process a press of a character key. ; cmp dl,59 ;at the end of the line? je editrec1 ;yes, then ignore keypress stosb ;deposit character in record mov ah,10 ;then print it mov cx,1 int 10h mov ah,2 ;advance the cursor inc dl int 10h jmp editrec1 ;return for more ; ;Process a press of the BACKSPACE key. ; bspace: cmp dl,27 ;any characters to delete? je editrec1 ;no, then ignore keypress mov ah,2 ;move cursor back one space dec dl int 10h mov ax,0A20h ;print a space character mov cx,1 int 10h dec di ;decrement buffer pointer by 1 mov byte ptr es:[di],32 ;insert an ASCII space jmp editrec1 ; ;Process a press of the ENTER key. ; enter: mov al,dl ;reset DI to beginning of line xor ah,ah sub ax,27 sub di,ax inc dh ;advance row number add di,32 ;advance pointer cmp dh,13 ;wrap around if necessary jne enter1 mov dh,7 sub di,192 enter1: mov dl,27 ;home the cursor mov ah,2 int 10h jmp editrec1 ;return to input loop ; ;Process a press of either Cursor-Left or Cursor-Right. ; extend: cmp ah,75 ;cursor left key? jne ext2 ;no, then branch cmp dl,27 ;already at left end of field? je ext1 ;yes, then ignore keypress mov ah,2 ;move cursor back one space dec dl int 10h dec di ;decrement buffer pointer ext1: jmp editrec1 ;return ext2: cmp ah,77 ;cursor right key? jne ext3 ;no, then branch cmp dl,59 ;cursor in last column? je ext1 ;yes, then ignore keypress mov ah,2 ;advance cursor inc dl int 10h inc di ;increment buffer pointer jmp editrec1 ;return ; ;Process a press of either Cursor-Up or Cursor-Down. ; ext3: cmp ah,72 ;cursor up key? jne ext5 ;no, then branch dec dh ;decrement row number sub di,32 ;set pointer to previous line cmp dh,6 ;wrap around if necessary jne ext4 mov dh,12 add di,192 ext4: mov ah,2 ;move the cursor int 10h jmp editrec1 ;return for another keypress ext5: cmp ah,80 ;cursor down key? jne ext6 ;no, then branch inc dh ;increment row number add di,32 ;set pointer to next line cmp dh,13 ;wrap around if necessary jne ext4 mov dh,7 sub di,192 jmp ext4 ;move cursor and return ; ;End the edit routine when F1 is pressed. ; ext6: cmp ah,59 ;F1 key? jne ext4 ;no, then ignore keypress mov ah,1 ;hide the cursor mov ch,20h int 10h mov si,offset menuline1 ;restore menu line call write_menu pop di ;recover starting address mov al,32 ;ASCII space character mov cx,192 ;192 bytes per record repe scasb ;check for non-space character jne ok ;OK if non-space found stc ;set CF to indicate blank entry ret ok: clc ;clear CF to indicate valid record ret edit_record endp ; ;------------------------------------------------------------------------------ ;FIND_POSITION returns the new index of the record addressed by SI. ;Entry: SI - record address | Exit: CL - record number ;------------------------------------------------------------------------------ find_position proc near mov cl,1 ;set index for first record cmp numrec,0 ;any records to examine? je find_exit ;no, then exit find1: mov al,cl ;get index in AL push cx ;save it call record_address ;get address of next record push si ;save new record address mov cx,32 ;32 bytes per record find2: cmpsb ;compare records ja next_record ;check next record jb slot_found ;alphabetical slot found loop find2 ;goto next byte if these are equal jmp short slot_found ;slot found if all equal next_record: pop si ;clean up the stack pop cx inc cl ;next record number cmp cl,numrec ;all records searched? jbe find1 ;no, then loop back for more find_exit: ret ;yes, then we're done slot_found: pop si ;clean up the stack pop cx ret find_position endp ; ;------------------------------------------------------------------------------ ;SHOW_RECORD displays the record pointed to by RECPTR. ;------------------------------------------------------------------------------ show_record proc near mov al,recptr ;get current record number call record_address ;get record address in DI mov si,di ;transfer it to SI mov bl,record_attr ;set attribute to be used mov dx,071Bh ;set initial cursor position mov cx,6 ;6 lines to display show1: push cx ;save line counter push dx ;save cursor position mov cx,32 ;32 characters per line call writeln ;display one line pop dx ;retrieve cursor address inc dh ;increment row number pop cx ;retrieve line counter loop show1 ;loop until done ret show_record endp ; ;------------------------------------------------------------------------------ ;RECORD_ADDRESS returns the offset address and slot number of a record. ;Entry: AL - record number | Exit: DI - record address ; | AL - slot number ;------------------------------------------------------------------------------ record_address proc near mov di,offset index_table ;point DI to index table mov cl,maxrec ;set counter xor ch,ch repne scasb ;search for current record number inc cx ;increment counter mov al,maxrec ;calculate offset address in AX sub al,cl push ax ;save slot number mul record_length add ax,offset data_buffer mov di,ax ;transfer address to DI pop ax ;recover slot number ret record_address endp ; ;------------------------------------------------------------------------------ ;WRITE_MENU displays a line of text on the window's menu line. ;Entry: DS:SI - address of text ;------------------------------------------------------------------------------ write_menu proc near mov ah,2 ;position the cursor mov dx,0E14h mov bh,video_page int 10h mov ax,0920h ;erase current menu line mov bl,menu_attr mov cx,40 int 10h wm1: lodsb ;get a character or al,al ;exit if it's the delimiter je wm2 mov ah,0Eh ;write the character int 10h jmp short wm1 ;loop until done wm2: ret write_menu endp ; ;------------------------------------------------------------------------------ ;WRITELN displays a string. ;Entry: DS:SI - string address ; BL - attribute ; CX - string length ; DH,DL - starting row and column ;------------------------------------------------------------------------------ writeln proc near mov bh,video_page ;set page number for output write1: mov ah,2 ;position cursor int 10h lodsb ;get one byte push cx ;save count mov cx,1 ;zero repetitions mov ah,9 ;int 10h function - write c/a int 10h ;write character/attribute inc dl ;advance cursor pop cx ;retrieve character count loop write1 ;loop until done ret writeln endp ; ;------------------------------------------------------------------------------ ;READLN accepts input of a string entered from the keyboard. ;Entry: ES:DI - buffer address | Exit: CL - string length ; DH,DL - cursor start position | ; CL - max length accepted | ;------------------------------------------------------------------------------ maxlen db ? ;maximum string length ; readln proc near mov maxlen,cl ;save max length mov ah,2 ;set cursor to start position mov bh,video_page int 10h call show_cursor ;display the cursor xor cl,cl ;initialize counter ; ;Wait for a keypress. ; read1: call getkey ;get a character cmp al,13 ;ENTER key? je read_exit ;yes, then exit cmp al,27 ;ESC key? jne read2 ;no, then branch xor cl,cl ;zero length jmp short read_exit ;exit read2: cmp al,8 ;backspace key? je backspace ;yes, then do backspace function cmp al,32 ;ASCII 32 or greater? jb read1 ;no, then ignore it cmp al,126 ;ASCII 126 or less? ja read1 ;no, then ignore keypress cmp cl,maxlen ;room for another entry? je read1 ;no, then ignore it ; ;Process the press of a character key. ; stosb ;deposit character in buffer push cx ;save character count mov ah,10 ;print the character mov cx,1 int 10h inc dl ;advance the cursor mov ah,2 int 10h pop cx ;retrieve count inc cl ;update count jmp read1 ;go back for more ; ;Process a press of the BACKSPACE key. ; backspace: or cl,cl ;any characters to delete? je read1 ;no, then ignore keystroke push cx ;save count dec dl ;move cursor back one space mov ah,2 int 10h mov ah,10 ;print a space character mov al,32 mov cx,1 int 10h pop cx ;retrieve count dec cl ;decrement it dec di ;decrement buffer pointer jmp read1 ;go back for more ; ;Hide the cursor and return. ; read_exit: mov ah,1 ;hide the cursor mov ch,20h int 10h ret readln endp ; ;------------------------------------------------------------------------------ ;SHOW_CURSOR displays the cursor and discounts EGA cursor emulation logic. ;Entry: NEW_CURSOR - starting and ending scan lines ;------------------------------------------------------------------------------ show_cursor proc near cmp adapter,2 ;is an EGA currently active? jne cursor1 ;no, then branch push es ;save ES mov ax,bios_data ;point ES to BIOS data area mov es,ax assume es:bios_data push infobyte ;save EGA info byte or ega_info,1 ;disable EGA cursor emulation cursor1: mov ah,1 ;display the cursor mov cx,new_cursor int 10h cmp adapter,2 ;is an EGA active? jne cursor_exit ;no, then exit pop infobyte ;restore EGA info byte pop es ;restore ES assume es:nothing cursor_exit: ret show_cursor endp ; ;------------------------------------------------------------------------------ ;CLEAR_WINDOW clears the record currently displayed in the window. ;------------------------------------------------------------------------------ clear_window proc near mov ax,0600h ;interrupt 10h, function 6 mov cx,071Bh mov dx,0C3Bh mov bh,record_attr int 10h ret clear_window endp ; ;------------------------------------------------------------------------------ ;IOSET vectors interrupts 1Bh, 23h and 24h to internal handlers. IORESET ;restores the original vector values. ;------------------------------------------------------------------------------ ioset proc near push es ;save ES mov ax,351Bh ;get interrupt 1Bh vector int 21h mov old1Bh_segment,es ;save it mov old1Bh_offset,bx mov ah,25h ;point it to an IRET instruction mov dx,offset ioexit int 21h mov ax,3523h ;get interrupt 23h vector int 21h mov old23h_segment,es ;save it mov old23h_offset,bx mov ah,25h ;point it to an IRET instruction mov dx,offset ioexit int 21h mov ax,3524h ;get interrupt 24h vector int 21h mov old24h_segment,es ;save it mov old24h_offset,bx mov ah,25h ;then set it to IOERR routine mov dx,offset ioerr int 21h pop es ;restore ES ret ioset endp ; ioreset proc near mov ax,2524h ;restore interrupt 24h vector mov dx,old24h_offset push ds assume ds:nothing mov ds,old24h_segment int 21h mov ax,2523h ;restore interrupt 23h vector mov dx,old23h_offset mov ds,old23h_segment int 21h mov ax,251Bh ;restore interrupt 1Bh vector mov dx,old1Bh_offset mov ds,old1Bh_segment int 21h pop ds assume ds:code ret ioreset endp ; ;------------------------------------------------------------------------------ ;FINISH loads the data file, resets interrupt vectors, and terminates. ;------------------------------------------------------------------------------ finish proc near ; ;Open the specified data file for reading. ; mov ax,3D00h ;open file for reading mov dx,offset filespec ;point DX to ASCIIZ filespec int 21h jnc finish3 ;branch if no error mov ah,9 ;print 'File not found' mov dx,offset errmsg1 int 21h cmp reload,0 ;was this an attempted reload? je endfin ;no, then exit mov al,old_numrec ;yes, then restore parameters mov es:[numrec],al mov al,old_recptr mov es:[recptr],al mov al,old_fileflag mov es:[fileflag],al endfin: ret ;and exit ; ;Load the data file into memory. ; finish3: mov bx,ax ;transfer file handle to BX push ds ;exchange DS and ES push es pop ds pop es mov ah,3Fh ;read record count byte mov cx,1 mov dx,offset numrec int 21h jc close ;branch on error mov al,ds:[maxrec] ;make sure NUMREC <= MAXREC cmp al,ds:[numrec] jae finish4 mov ds:[numrec],al ;adjust if it isn't finish4: mov al,ds:[numrec] ;calculate number of bytes to read mul record_length mov cx,ax ;transfer number of bytes to CX mov ah,3Fh ;DOS function 3Fh - read file mov dx,offset data_buffer ;point DX to buffer area int 21h ;read all records from disk close: mov ah,3Eh ;close file int 21h mov ds:[fileflag],1 ;set filespec flag push ds ;swap DS and ES again push es pop ds pop es ; ;Initialize the record index table. ; finish5: mov di,offset index_table ;point DI to table area xor al,al ;zero AL mov cl,es:[maxrec] ;set counter xor ch,ch rep stosb ;zero all bytes mov cl,es:[numrec] ;set CX to number of records xor ch,ch jcxz finish7 ;exit if there are none mov di,offset index_table ;reset DI mov al,1 ;initialize AL finish6: stosb ;set one index byte inc al ;increment index loop finish6 ;loop until done ; ;Copy new filespec into old data space if this is a reload. ; finish7: cmp reload,0 ;is this a reload je finish8 ;no, then branch mov si,offset filespec ;point SI and DI to filespec areas mov di,si mov cx,126 ;set counter rep movsb ;transfer text ret ;done - exit ; ;Save and replace all required interrupt vectors. ; finish8: mov ax,3508h ;get interrupt 8 vector int 21h mov old8h,bx ;save it mov old8h[2],es mov ah,25h ;point it to the TIMER routine mov dx,offset timer int 21h mov ax,3509h ;get interrupt 9 vector int 21h mov old9h,bx ;save it mov old9h[2],es mov ah,25h ;point it to KEYBOARD routine mov dx,offset keyboard int 21h mov ax,3510h ;get interrupt 10h vector int 21h mov old10h,bx ;save it mov old10h[2],es mov ah,25h ;point it to VIDEO mov dx,offset video int 21h mov ax,3513h ;get interrupt 13h vector int 21h mov old13h,bx ;save it mov old13h[2],es mov ah,25h ;point it to BDISK mov dx,offset bdisk int 21h mov ax,3528h ;get interrupt 28h vector int 21h mov old28h,bx ;save it mov old28h[2],es mov ah,25h ;point it to BACKPROC mov dx,offset backproc int 21h ; ;Calculate amount of memory to reserve and terminate-but-stay-resident. ; mov dx,offset program ;display notice and hot key mov ah,9 ;with DOS function 9 int 21h mov al,maxrec ;get max number of records mul record_length ;multiply by 192 mov dx,ax ;transfer figure to DX add dx,(offset data_buffer - offset code + 15) mov cl,4 ;convert bytes to paragraphs shr dx,cl mov ax,3100h ;load function and return codes int 21h ;terminate-but-stay-resident finish endp ; ;----------------------------------------------------------------------------- ;Data space to be used after Cardfile is resident in memory. ;----------------------------------------------------------------------------- pc = $ screen_buffer = pc ;video memory buffer pc = pc + 10 * 44 * 2 index_table = pc ;record index table pc = pc + 512 filespec = pc ;file specification pc = pc + 128 data_buffer = pc ;record buffer ; ;------------------------------------------------------------------------------ ;INITIALIZE prepares the program for residency. ;------------------------------------------------------------------------------ initialize proc near assume ds:code errmsg1 db 13,10,"File not found",13,10,"$" errmsg2 db 13,10,"Critical Error Flag not found",13,10,"$" old_numrec db ? old_recptr db ? old_fileflag db ? ; ;See if the program is already resident in memory. ; init1: mov word ptr [begin],0 ;zero word to avoid false match xor bx,bx ;initialize search segment mov ax,cs ;record current segment in AX init2: inc bx ;increment search segment cmp ax,bx ;reached current segment? je init3 ;yes, then this is the first load mov es,bx ;point ES to search segment mov si,offset begin ;point SI and DI to ID offset mov di,si mov cx,16 ;check 16 characters cld ;clear DF repe cmpsb ;compare the strings jne init2 ;continue search if compare failed ; ;Cardfile is already installed. Set the reload flag and save parameters. ; mov reload,1 ;set flag mov al,es:[numrec] ;save parameters mov old_numrec,al mov al,es:[recptr] mov old_recptr,al mov al,es:[fileflag] mov old_fileflag,al mov es:[numrec],0 ;initialize counters and flags mov es:[recptr],1 mov es:[fileflag],0 jmp short parse ;branch to parsing code ; ;Determine which version of DOS is running. ; init3: mov ah,30h ;DOS function 30h int 21h mov dos_version,al ;major version number ; ;Get and save the address of the INDOS flag. ; mov ah,34h ;function 34h int 21h ;get address mov dos_segment,es ;save segment mov indos_offset,bx ;save offset ; ;Get and save the address of the critical error flag. ; mov ax,3E80h ;CMP opcode mov cx,2000h ;max search length mov di,bx ;start at INDOS address init4: repne scasw ;do the search jcxz init5 ;branch if search failed cmp byte ptr es:[di+5],0BCh ;verify this is it je found ;branch if it is jmp init4 ;resume loop if it's not init5: mov cx,2000h ;search again inc bx ;search odd addresses this time mov di,bx init6: repne scasw ;look for the opcode jcxz notfound ;not found if loop expires cmp byte ptr es:[di+5],0BCh ;verify this is it je found jmp init6 notfound: mov ah,9 ;flag not found mov dx,offset errmsg2 int 21h ret found: mov ax,es:[di] ;get flag offset address mov errflag_offset,ax ;save it push cs ;reset ES to the code segment pop es ; ;Parse the command line and create a complete filespec. ; parse: mov di,82h ;point DI to command line text cmp byte ptr [di-2],2 ;less than 2 characters entered? jnb parse0 ;no, then continue jmp finish5 ;yes, then skip load routine parse0: mov si,di ;point SI to command line text mov di,offset filespec ;point DI to buffer parse1: cmp byte ptr [si],32 ;advance to first non-space jne parse2 inc si jmp parse1 parse2: cmp byte ptr [si+1],":" ;leading drive specifier? je parse4 ;yes, then filespec is complete mov ah,19h ;get current drive int 21h add al,65 ;convert to ASCIIZ mov ah,":" ;complete drive specifier mov word ptr [di],ax ;write drive spec to buffer add di,2 ;advance DI cmp byte ptr [si],"\" ;leading backslash? je parse4 ;yes, then filespec is complete mov byte ptr [di],"\" ;fill in the backslash inc di push si ;save SI and DI push di mov ah,47h ;get current path mov si,di xor dl,dl ;default drive int 21h ;append path to drive spec pop di ;restore SI and DI pop si cmp byte ptr [di],0 ;anything returned? je parse4 ;no, then filespec is complete parse3: inc di ;advance to end of string cmp byte ptr [di],0 jne parse3 mov byte ptr [di],"\" ;insert trailing backslash inc di parse4: mov al,[si] ;append entry to filespec string cmp al,13 je parse5 mov [di],al inc si inc di jmp parse4 parse5: mov byte ptr [di],0 jmp finish ;load data file and exit initialize endp ; code ends end begin