Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!rutgers!uwvax!astroatc!vidiot!brown
From: brown@vidiot.UUCP (Vidiot)
Newsgroups: comp.binaries.ibm.pc.d
Subject: Re: Warm-boot program
Message-ID: <384@vidiot.UUCP>
Date: 5 Jan 90 19:02:07 GMT
References: <5894@uhccux.uhcc.hawaii.edu> <1990Jan4.124333.25943@tvcent.uucp>
Reply-To: brown@vidiot.UUCP (Vidiot)
Organization: Vidiot's Hangout
Lines: 78

In article <1990Jan4.124333.25943@tvcent.uucp> andrew@tvcent.UUCP (Andrew Cowie) writes:
<
<What you need is to use the same interrupt that is generated when you
<type Ctrl-Alt-DEL. This interrupt is interrupt 19 hex, 25 in decimal.
<This can be generated with the assembly command INT 19.
<
<A small file can be made by using DEBUG. (comes with DOS) A full
<assembler could be used, but is unnecessary.

While it is true that a full assembler is not needed, it is if you want to
but it into a library and incorporate it into a program that you are writing.
The following assembly code will compile to back a standalone reboot program
and a .obj that can be used to be placed into a library.  I have used it with
QuickBASIC.


                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
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