print macro string lea dx,string mov ah,9 int 21h endm cseg segment para public 'CODE' assume cs:cseg,ds:cseg,ss:cseg,es:cseg org 100h ;end of program segment prefix enter: jmp install ;skip over data int1ch equ this dword int1cip dw 0 int1ccs dw 0 int16h equ this dword int16ip dw 0 int16cs dw 0 int9h equ this dword int9ip dw 0 int9cs dw 0 semaphore db 0 dcount dw 0 counter dw 0 dswitch db 0 kswitch db 0 message db 65 dup(0) crlf_sw db 0 on_sw db 0 message_len dw 0 char_count dw 0 period dw 0 int_9: ; this is the keyboard interrupt, ; if int_9 is pressed then reset the deadman ; first set the deadman ; pushf call cs:int9h push ax mov ax,cs:dcount mov cs:counter,ax ; process the keystroke ; now we can check to see if there was a keystroke ; check the semaphore mov al,1 lock xchg cs:semaphore,al cmp al,1 jne no_sem pop ax iret no_sem: sti mov ax,0100h int 16h jz no_key cmp ax,2000h jne no_key ; check the shift status mov ah,2 int 16h ; the shift status comes in al and al,0ah cmp al,0ah jne no_key mov ah,0 int 16h xor cs:on_sw,1 jnz blopper call blip call blip jmp no_key blopper: call blop call blop call blop no_key: mov cs:semaphore,0 pop ax iret int_16: ; check to see if we have been called upon sti cmp ax,'DM' jne i16_1 cmp dx,'KG' jne i16_1 mov ax,'EC' push cs pop es iret i16_1: ; this is the keyboard interrupt cmp cs:semaphore,1 je no_kb cmp cs:on_sw,1 je no_kb cmp cs:kswitch,1 jne no_kb ; this is where we have to simulate the keystrokes cmp ah,2 jge no_kb cmp ah,0 jl no_kb ; its for us! ; message has the bytes to get ; char_count has the number of bytes left to send ; message_len has the length of the message ; message_len - char_count has the offset into message cmp ah,0 je int16_f0 jmp int16_f1 ; interrupt 16 func 1 ; same as 0 except no dec of char_count int16_f0: cmp cs:char_count,0 je do_cr0 push bx mov bx,cs:message_len sub bx,cs:char_count mov al,cs:message[bx] dec cs:char_count pop bx jmp exit_char do_cr0: ; this is if there is cr in the works mov cs:kswitch,0 push ax mov ax,cs:dcount mov cs:counter,ax pop ax cmp cs:crlf_sw,0 je no_kb mov al,13 jmp exit_char no_kb: jmp cs:int16h ; interrupt 16 func 1 ; same as 0 except no dec of char_count int16_f1: cmp cs:char_count,0 je do_cr1 push bx mov bx,cs:message_len sub bx,cs:char_count mov al,cs:message[bx] pop bx ; all popped out exit_char: mov ah,0 cmp ah,1 clc db 0cah,02,00 ; ret far 2 do_cr1: ; this is if there is cr in the works cmp cs:crlf_sw,0 je no_kb mov al,13 jmp exit_char int_1c: pushf call cs:int1ch cmp cs:on_sw,1 je no_counter cmp cs:kswitch,1 je no_counter ; decrement the counter dec cs:counter ; check for warning cmp cs:counter,40 jne no_bloop sti call blip call blop call blip no_bloop: cmp cs:counter,0 jg no_counter ; set the kswitch push ax mov ax,cs:message_len mov cs:char_count,ax pop ax mov cs:kswitch,1 no_counter: iret tone: mov dx,3 ; tone rate mov bx,240 ; starting freq mov cx,750 ; ending frequency cmp si,0 jg do_blip ; here we do blop mov bx,630 ; starting freq mov cx,150 ; ending frequency do_blip: ; turn on tone i0: push cx push bx in al,61h or al,3 out 61h,al ; loop parameters mov cx,bx ; set frequency mov dx,12h mov ax,34deh div cx mov cx,ax ; set tone mov al,cl out 42h,al mov al,ch out 42h,al i2: loop i2 pop bx pop cx cmp bx,cx je ip3 add bx,si jmp i0 ip3: ;turn off tone in al,61h and al,11111100b out 61h,al ret blip: push ax push bx push cx push dx push si mov si,30 call tone pop si pop dx pop cx pop bx pop ax ret blop: push ax push bx push cx push dx push si mov si,-30 call tone pop si pop dx pop cx pop bx pop ax ret install proc near ; check the command line mov cl,byte ptr ds:[80h] mov ch,0 cmp cx,2 jg inst_1 call blop call blop call blop print error1 int 20h inst_1: ; check to see if we are already installed mov ax,'DM' mov dx,'KG' int 16h cmp ax,'EC' jne inst_9 ; its already installed call blop print mess1 mov no_inst,1 jmp set_parms inst_9: ; set_parms: mov cl,byte ptr ds:[80h] mov ch,0 mov si,81h cld p_loop: lodsb cmp al,20h je end_p_loop cmp al,13 je end_p_loop cmp al,'/' je got_slash end_p_loop: loop p_loop jmp exit_prog got_slash: lodsb call upper cmp al,"O" je do_on cmp al,"F" je do_off cmp al,"C" je do_CRLF cmp al,"M" je do_message cmp al,"P" je do_P jmp end_p_loop do_p: ; got the period lodsb dec cx jg no_exit_prog jmp exit_prog no_exit_prog: push cx mov cl,100 mov ah,0 and al,0fh mul cl mov bx,ax pop cx lodsb dec cx jbe exit_prog push cx mov cl,10 mov ah,0 and al,0fh mul cl add bx,ax pop cx lodsb dec cx jbe exit_prog mov ah,0 and al,0fh add bx,ax mov es:period,bx ; multiply by 18.5 times period push cx mov cx,bx mov ax,37 mul cx inc ax shr ax,1 mov es:dcount,ax mov es:counter,ax pop cx jmp ret_loop do_on: mov es:on_sw,0 jmp ret_loop do_off: mov es:on_sw,1 jmp ret_loop do_crlf: mov es:crlf_sw,1 jmp ret_loop ret_loop: dec cx jle exit_prog jmp p_loop do_message: ; here the message must be transferred mov es:message_len,0 lea di,message cld jmp end_m_loop m_loop: lodsb cmp al,'/' jne no_got_slash jmp got_slash no_got_slash: cmp al,13 je exit_prog stosb inc es:message_len end_m_loop: loop m_loop jmp exit_prog ; exit the routine exit_prog: ; get the interrupts cmp no_inst,1 jne ok_install int 20h ok_install: mov ax,3509h int 21h mov int9ip,bx mov int9cs,es mov ax,3516h int 21h mov int16ip,bx mov int16cs,es mov ax,351ch int 21h mov int1cip,bx mov int1ccs,es ; set the interrupts push cs pop es lea dx,int_9 mov ax,2509h int 21h lea dx,int_16 mov ax,2516h int 21h lea dx,int_1c mov ax,251ch int 21h push cs pop es print mess2 lea dx,install int 27h upper: cmp al,'a' jge up_1 ret up_1: cmp al,'z' jle up_2 ret up_2: sub al,32 ret no_inst db 0 error1 db 'The correct form of the DEADMAN command is:',13,10 db 'DEADMAN /Mmessage /C /Pnnn /F /O',13,10 db 'where message is a message that will appear every',13,10 db 'nnn seconds when the keyboard is not being used.',13,10 db 'Anything following the /M up to the next /',13,10 db 'or the end of the line is considered a message.',13,10 db 'A message can be up to 64 bytes long.',13,10 db 'DEADMAN will beep a second before he goes off so',13,10 db 'touch the shift key if you want to stop him.',13,10 db 'The nnn after the /P is the period that DEADMAN',13,10 db 'will wait between messages in seconds and can be',13,10 db 'from 001 to 999. Leading zeros are required!',13,10 db 'The /C means follow the message with a carriage',13,10 db 'return - line feed. /F means turn off DEADMAN.',13,10 db '/O means turn DEADMAN back on.',13,10,'$' mess1 db 13,10,'DEADMAN is already installed - updating...' db 13,10,'$' mess2 db 'DEADMAN is resident.',13,10 db 'Press Alt-Left Shift D to toggle deadman on and off.',13,10 db 'DEADMAN - Asleep at the wheel software.',13,10 db 'Copyright 1987 by Keith P. Graham',13,10 db 'Released to the public domain at PC-Rockland',13,10 db '(914) 353-2176',13,10,'$' install endp cseg ends end enter