alexc@psu-cs.cs.pdx.edu (Alex Chan) (03/14/89)
Hi there,
Is it possible to write a program to reboot a PC ?
( I mean a " cold boot " with memory check. ) and how
could I do it ?
If someone have the binary or the sources for such
program " reboot " program, could you please e-mail
to me. Thank you in advance.
------------
Alex M. Chan
UUCP: uunet!tektronix!{psu-cs,reed,ogccse}!qiclab!tanya!root
DISCLAIMER : The above stated is only my personal opinion, in no way it represent my employer or my organization....
Alex M. Chan
AMC Microsystems Inc. ( Private research and developement )
UUCP: uunet!tektronix!{psu-cs,reed,ogccse}!qiclab!tanya!root
DISCLAIMER : The above stated is only my personal opinion, in no way it represent my employer or my organization....todd@stiatl.UUCP (Todd Merriman) (03/15/89)
In article <830@psueea.UUCP> alexc@psu-cs.cs.pdx.edu (Alex Chan) writes: > > Is it possible to write a program to reboot a PC ? ifdef DOCUMENTATION ; **************************************************************************** REBOOT.ASM 12/18/87 Todd Merriman .MODULE reboot .LIBRARY clib .TYPE function .APPLICATION system .SYSTEM msdos .AUTHOR Todd Merriman .LANGUAGE Assembly .DESCRIPTION Reboot the computer .ARGUMENTS void reboot(); .NARRATIVE The reboot function transfers program control to the CPU reset vector, and a system reset is performed. This could be used in a case where a device driver was modified. .CAUTION Be sure there are no open files, or any I/O not completed. .RETURNS void .NOTICE Copyright (c) 1987 Future Communications, Atlanta, Georgia .ENDOC END DOCUMENTATION ; **************************************************************************** endif .XLIST INCLUDE \HEADER\C.MAC ; symbols and macros for Microsoft .LIST ; **************************************************************************** ; data ; **************************************************************************** DSEG ; begin data section RES_VEC DW 0FFF0H,0F000H ; reset vector ENDDS ; end data section ; **************************************************************************** ; code ; **************************************************************************** PSEG ; begin program section CFUN reboot ; C function declaration PUSH BP MOV BP,SP LEA SI,RES_VEC ; load reset vector JMP DWORD PTR DS:[SI] ; jump there POP BP ; this code for good form only RET CFEND reboot ; end C function ENDPS ; end program section END ; end assembly ; **************************************************************************** ; reboot program ; this is a test for the reboot function ; **************************************************************************** PAGE 59,132 ; ; Outline for assembly programs to .COM files ; .XLIST INCLUDE \LAT\HEADER\CSUB.MAC .LIST CODE SEGMENT PUBLIC ASSUME CS:CODE, DS:CODE, SS:CODE, ES:CODE ORG 100H ; .COM origin MAIN PROC FAR START: CCALL reboot INT 20H ; to DOS MAIN ENDP CODE ENDS END START ; **************************************************************************** ; End REBOOT.ASM ; **************************************************************************** ...!gatech!stiatl!todd Todd Merriman 404-377-TOFU Atlanta, GA
nclamber@ndsuvax.UUCP (Pete Lambertz) (03/17/89)
CSEG SEGMENT
org 100h
.MODEL TINY
ASSUME CS:CSEG, DS:CSEG, SS:CSEG
org 100h
PARK: mov ah,25h
mov al,6ah
mov dx,0ffffh
mov ds,dx
xor dx,dx
int 21h
int 6ah
int 20h
CSEG ENDS
END PARK
this can then be assembled and linked to a .com file.
If you wanted to reboot from Turbo C you could write
void reboot(void)
{
setvector(0x6a, MK_FP(FP_SEG(0xFFFF), FP_OFF(0x0000));
geninterrupt(0x6a);
}
main()
{
reboot();
}
--
Pete Lambertz North Dakota State University, Fargo, ND 58105
UUCP: ...!uunet!ndsuvax!nclamber
BITNET: nclamber@ndsuvax.bitnet
INTERNET: nclamber@plains.NoDak.edu
#! rnews 1580
Path: psuvm.bitnet!cunyvm!ndsuvm1!nddavidsen@steinmetz.ge.com (Wm. E. Davidsen) (03/17/89)
In order to cold boot your computer you must change the value of a byte
in memory and jump to FFFF:0000. I can't find the byte offhand, but it
determines warm or cold boot. The program posted in response to your
inquery doesn't seem to diddle the flag byte, and may just give a warm
boot. You can get that with one instruction:
JMPF FFFF:0000
I freely admit that I might have missed the byte diddling, but I don't
think so. There was a program called reboot which took an argument W or
C and performed the correct boot.
================================================================
New mailing address: wedu@crd.ge.com
We are no longer ge-crd.arpa and mail will stop working to that address
in the *very* near future.
Note: flames and hate mail may still use the old address ;-{
================================================================
We now return you to our regularly scheduled signature...
--
bill davidsen (wedu@crd.GE.COM)
{uunet | philabs}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -memvp@v7fs1.UUCP (Mike Van Pelt) (03/17/89)
Other people have mentioned that you just jump to FFFF:0. The other
trick is location 0:0472. If you store hex 1234 into that word
location, you will get a warm boot. If you store anything else
there, you will get a cold boot.
Quickie Debug script: (Real hackers don't use MASM!)
debug
a 100
push ds
mov ax,0
mov ds,ax
mov ax,1234 (make this zero or something for cold boot.)
mov [0472],ax
pop ds
jmp ffff:0
nreboot.com
r cx
12
w
--
I would like to electrocute everyone who uses the | Mike Van Pelt
word 'fair' in connection with income tax policies. | Video 7
-- William F. Buckley | ...ames!vsi1!v7fs1!mvpsimcha@humming.UUCP (Simcha Lerner) (03/18/89)
In article <830@psueea.UUCP> alexc@psu-cs.cs.pdx.edu (Alex Chan) writes: > >Hi there, > > Is it possible to write a program to reboot a PC ? > ( I mean a " cold boot " with memory check. ) and how > could I do it ? > This is quite easy. A cold boot is initiated by jumping to address FFFF:0000 in real mode - this being the address that the processor goes to in the event of a reset. If you wish a warm boot, load 1234 into 40:72 (all of these numbers are hex). This will cause the POST (Power On Self Test) to be skipped. Given the tiny size of this program, you can easily create it via debug. Simcha Lerner harvard!humming!simcha
alexc@psueea.uucp (Alex Chan) (03/19/89)
I have received quite a few postings / e-mail on how to do a reboot from a program in C, ASM and using DEBUG.COM. I would like to say a sincerely thank you to those who have contributed the solution(s). So here it comes.... +---------------------------------------------------+ | ______ /| | / / / /| | --/ /_ __. ____ /_ __ , ____. . ' | | (_/ / /_(_/|_/ / <_/ <_ / (_/_(_) (_/_ o | | / | | ' | +---------------------------------------------------+ Alex M. Chan AMC Microsystems Inc. ( Private research and developement ) UUCP: uunet!tektronix!{psu-cs,reed,ogccse}!qiclab!tanya!root DISCLAIMER : The above stated is only my personal opinion, in no way .....it represent my employer or my organization....
brown@nicmad.UUCP (Vidiot) (03/20/89)
In article <265@humming.UUCP> simcha@humming.UUCP (Simcha Lerner) writes: <In article <830@psueea.UUCP> alexc@psu-cs.cs.pdx.edu (Alex Chan) writes: <> <>Hi there, <> <> Is it possible to write a program to reboot a PC ? <> ( I mean a " cold boot " with memory check. ) and how <> could I do it ? <> < <This is quite easy. A cold boot is initiated by jumping to address <FFFF:0000 in real mode - this being the address that the processor <goes to in the event of a reset. < <If you wish a warm boot, load 1234 into 40:72 (all of these numbers are <hex). This will cause the POST (Power On Self Test) to be skipped. < <Given the tiny size of this program, you can easily create it via debug. Yep, it is very easy. Attached is an assembly listing that you run through MASM to create a stand-alone program and an object file that can be linked in with other programs (which I have done). page 60,132 title REBOOT.ASM = Performs a Warm System Boot = PUBLIC REBOOT ;=======================================================================; ; ; ; This segment is used to reference a "JMP" instruction in ; ; ROM which branch to the reboot code in ROM. ; ; ; ;=======================================================================; rom_seg segment at 0ffffH boot_jmp label far rom_seg ends ;=======================================================================; ; ; ; This segment is used to reference a word in the BIOS data ; ; area which is used to determine if a WARM or COLD reboot ; ; should be performed by the reboot code in ROM. ; ; ; ;=======================================================================; bios_seg segment at 0040H org bios_seg+72H boot_flags label word bios_seg ends cold_boot equ 0000H ;Value to indicate COLD reboot warm_boot equ 1234H ;Value to indicate WARM reboot page ;=======================================================================; ; ; ; The following lines set the boot flags in the BIOS Data ; ; Area and then invoke the boot code in the BIOS ROM. ; ; ; ;=======================================================================; code_seg segment assume CS:code_seg, DS:code_seg org code_seg+100H reboot proc mov AX,bios_seg mov DS,AX ;Point to BIOS Data Area assume DS:bios_seg mov boot_flags,warm_boot assume DS:rom_seg jmp boot_jmp ;Jump to Reboot Code reboot endp code_seg ends end -- harvard-\ att--\ Vidiot ucbvax!uwvax!astroatc!nicmad!brown rutgers-/ decvax--/ ARPA/INTERNET: nicmad!brown%astroatc.UUCP@spool.cs.wisc.edu
wws@rruxd.UUCP (W W Scott) (03/22/89)
In article <830@psueea.UUCP>, alexc@psu-cs.cs.pdx.edu (Alex Chan) writes: > > Is it possible to write a program to reboot a PC ? > ( I mean a " cold boot " with memory check. ) and how > could I do it ? > > If someone have the binary or the sources for such > program " reboot " program, could you please e-mail > to me. Thank you in advance. Please mail the source to me also.
malloy@nprdc.arpa (Sean Malloy) (03/23/89)
In article <375@rruxd.UUCP> wws@rruxd.UUCP (W W Scott) writes: >In article <830@psueea.UUCP>, alexc@psu-cs.cs.pdx.edu (Alex Chan) writes: >> >> Is it possible to write a program to reboot a PC ? >> ( I mean a " cold boot " with memory check. ) and how >> could I do it ? >> >> If someone have the binary or the sources for such >> program " reboot " program, could you please e-mail >> to me. Thank you in advance. > >Please mail the source to me also. I got this out of the MSDOS archives at SIMTEL20: > > From: hplabs!hpcea!hpfcdc!hpldola!hp-lsd!nmsu-ee!rusty (Rusty Baldwin) > Newsgroups: comp.sys.ibm.pc > Subject: Re: how do i do a pc warm boot from software? > Date: 7 Oct 87 22:00:50 GMT > > The following are two short routines to do a warm or a coldboot. > Hope they help you out. > > > COLDBOOT: > 70A2:0100 BA4000 MOV DX,0040 > 70A2:0103 8EDA MOV DS,DX > 70A2:0105 BB7200 MOV BX,0072 > 70A2:0108 C7070000 MOV WORD PTR [BX],0000 > 70A2:010C EA0000FFFF JMP FFFF:0000 > > WARMBOOT: > 70A2:0100 BA4000 MOV DX,0040 > 70A2:0103 8EDA MOV DS,DX > 70A2:0105 BB7200 MOV BX,0072 > 70A2:0108 C7073412 MOV WORD PTR [BX],1234 > 70A2:010C EA0000FFFF JMP FFFF:0000 > > > Rusty Baldwin > nmsu-ee!rusty Sean Malloy Navy Personnel Research & Development Center San Diego, CA 92152-6800 malloy@nprdc.navy.mil