F;,VN[OWIR wrote:
> I am looking for a piece of software that would sit in the boot sector of a
> hard disk and load an application thus making possible an embedded
> application without having to use an OS. Source code is needed. The
> application will be coded in C or C++ using the GCC compiler.

If you look at http://www.beroset.com you will find public domain source 
code loader.asm and a web page of explanation about how it words. 
However, you'll need to set up the registers and go into 32-bit 
protected mode if you're going to use gcc.  The loader currently does 
not do that.

Ed

Followup to:  <41407cf7_5@newsfeed.slurp.net>
By author:    "F;,VN[OWIR" <postmaster@localhost>
In newsgroup: comp.arch.embedded
>
> I am looking for a piece of software that would sit in the boot sector of a
> hard disk and load an application thus making possible an embedded
> application without having to use an OS. Source code is needed. The
> application will be coded in C or C++ using the GCC compiler.
>

Check out SYSLINUX, http://syslinux.zytor.com/ ; it has all the code
to run 32-bit gcc-compiled code with a simple API in addition to any
functions offered by the BIOS.

	-hpa

F;,VN[OWIR wrote:
> I am looking for a piece of software that would sit in the boot sector of a
> hard disk and load an application thus making possible an embedded
> application without having to use an OS. Source code is needed. The
> application will be coded in C or C++ using the GCC compiler.
> 
> please reply to this newsgroup.
> Thank you

Here is a piece of code that loads the boot sector of the second
hard disk (/dev/hdb or B:). The code can be compiled with
a currect version of GCC.

Please note that normal GCC code runs in 32 bit mode, but
a PC boots up in 16 bit mode. You need to create the code
to switch to 32 bit mode before calling the C main().

Also, it will be your responsibility to set up the
runtime environment of the code. The PC BIOS is
not available to run the hardware in 32 bit mode.

-------------

	.psize 40,110

#       **********************************************
#
#	  boot0x81.S - boot secondary hard drive MBR
#	  26.3.2003, TV
#
#	**********************************************

	.global _start		# not needed, to keep ld happy

#	Definitions
#	-----------

DRIVE=	0x81			# BIOS drive code (/dev/hdb)

BDISP=	0x10			# BIOS console output
BTTY=	0x0e			# BIOS TTY display

BDISK=	0x13			# BIOS disk I/O
BDREAD=	2			# BIOS disk read

WORD=	2			# sizeof(WORD)
PARA=	16			# paragraph size
BLKSZ=	512			# disk block size
BPARA=	BLKSZ/PARA		# block size in paragraphs

BOOTSG=	0x7c0			# boot segment
BSGOFF=	BLKSZ-WORD		# boot signature offset
BSIG=	0xaa55			# boot signature

	.page
#	Start up - move off boot area and normalise segments
#	----------------------------------------------------

	.text
	.code16

_start:	call getip		# push IP of next instruction
getip:	popw %ax		# get IP value
	subw $getip-_start,%ax	# entry IP value
	shrw $4,%ax		# extract segment part
	movw %cs,%dx		# get entry cs
	addw %dx,%ax		# canonical segment
	movw %ax,%ds		# address with canonical segment

	addw $BPARA,%ax		# offset past own size
	cmpw $BOOTSG-BPARA,%ax	# far enough below boot area?
	jbe ok			#  yes
	cmpw $BOOTSG+BPARA,%ax	# far enough above boot area?
	jae ok			#  yes
	movw $BOOTSG+2*BPARA,%ax # no - get a safe segment
	
ok:	movw %ax,%es		# set up target segment
	movw %ax,%ss		# set up
	movw $stktop,%sp	#  own stack
	
	xorw %si,%si		# no source offset
	xorw %di,%di		# no destination offset
	movw $BLKSZ/WORD,%cx	# block size in words
	cld			# process upward
	rep movsw		# move
	
	pushw %ax		# set up target segment
	pushw $switch		# set up target offset
	lret			# switch to new location

	.page
#	Read the target boot segment
#	----------------------------

switch:	movw $BOOTSG,%ax	# get boot segment
	movw %ax,%es		# set up
	xorw %bx,%bx		# target offset zero
	
	movw $1,%cx		# cylinder 0, sector 1
	movw $DRIVE,%dx		# target drive, head 0
	movb $BDREAD,%ah	# disk read
	movb $1,%al		# one block
	int $BDISK		# BIOS disk
	jc badrd		#  error

#	Check boot signature - enter boot if OK

	cmpw $BSIG,%es:BSGOFF(%bx) # signature OK?
	jne badsig		   #  no - don't trust

	push %es		# set up target segment
	push %bx		# set up target offset
	lret			# chain to loaded block

	.page
#	Boot error - complain and halt
#	------------------------------

badrd:	movw $ermsg1,%si	# -> read error message
	jmp toobad		# display and stop

badsig:	movw $ermsg2,%si	# -> boot signature message

toobad:	pushw %si		# save error pointer

	movw $banner,%si	# -> banner
	call pmsg		# display it

	popw %si		# -> error message
	call pmsg		# display it

	jmp .			# loop till ctrl-alt-del

	.page
#	Display an .asciiz  message from %ds:(%si)
#	------------------------------------------

pmsg:	lodsb			# get a byte
	orb %al,%al		# null?
	jz pmsgx		#   yes - exit
	
	pushw %si		# save pointer
	call pchr		# display the byte
	popw %si		# restore pointer
	
	jmp pmsg		# loop till done

pmsgx:	ret			# return


#	Display a character from %al
#	----------------------------

pchr:	movb $BTTY,%ah		# TTY output
	int $BDISP		# BIOS display
	
	ret			# return

	.page
#	Messages
#	--------

banner:	.asciz "\r\nboot0x81:  "
ermsg1:	.asciz "Read error\r\n"
ermsg2:	.asciz "No boot signature\r\n"


#	Boot block signature
#	--------------------

	.org BSGOFF

stktop:	.word BSIG		# boot signature

	.end _start


-------------


HTH

Tauno Voipio
tauno voipio (at) iki fi


PS. I'd rather send lengthy code pieces per E-mail, but you do not
     seem to have a valid address (and I'm a little suspicious
     of the name, too).

TV

On 2004-09-09, F;,VN[OWIR <postmaster@localhost> wrote:

> I am looking for a piece of software that would sit in the boot sector of a
> hard disk and load an application thus making possible an embedded
> application without having to use an OS. Source code is needed. The
> application will be coded in C or C++ using the GCC compiler.

Grub?

Redboot?

UBoot?

-- 
Grant Edwards                   grante             Yow!  I want EARS! I
                                  at               want two ROUND BLACK
                               visi.com            EARS to make me feel warm
                                                   'n secure!!

I am looking for a piece of software that would sit in the boot sector of a
hard disk and load an application thus making possible an embedded
application without having to use an OS. Source code is needed. The
application will be coded in C or C++ using the GCC compiler.

please reply to this newsgroup.
Thank you