#    ;;  dmesg.s

	# the documentation on syslog(2) seems to be slightly different
	# than what I observe from on strace. strace shows
	# a call to syslog(0xa,0,0) to apparently retrieve the size of the
	# buffer (?) and then a call to syslog(3,buffer,bufflen) to actually
	# retrieve data

	# something's wrong with the heap allocation --- if I use a fixed buffer, works fine!

#include <asm/unistd_32.h>

	.data
_syslog_bytes:
	.long	0
_heap_bottom:
	.long	0
_heap_top:
	.long	0
	

	.file "dmesg.s"

	.globl dmesg

dmesg:
	mov	$0xa,%ebx	# find out how many bytes? I guess -- 0xa is definitely not documented!
	mov	$0,%ecx
	mov	$0,%edx
	mov	$__NR_syslog,%eax
	int	$0x80

	mov	%eax,_syslog_bytes	# save the number of bytes 

	mov     $0,%ebx		# find the bottom of the heap
	mov     $__NR_brk,%eax	# 
	int	$0x80

	mov	%eax,_heap_bottom	# and save the bottom of heap in %r14
	mov	%eax,_heap_top	# %r13 will keep the top of the heap

	mov	_syslog_bytes,%eax
	add	%eax,_heap_top	

	mov	_heap_top,%ebx	# now ask to extend heap 
	mov	$__NR_brk,%eax
	int	$0x80

	mov	$3,%ebx		# do the actual call to syslog(2)
	mov	_heap_bottom,%ecx
	mov	_syslog_bytes,%edx
	mov	$__NR_syslog,%eax
	int	$0x80

	mov	%eax,_syslog_bytes	# actual number of bytes remaining
				# to write, and of course begins with what
				# syslog(2) returned...

write_loop:	
	mov	$1,%ebx
	mov	_heap_bottom,%ecx
	mov	_syslog_bytes,%edx
	mov	$__NR_write,%eax
	int	$0x80

	add	%eax,_heap_bottom
	sub	%eax,_syslog_bytes
	jnz	write_loop

	mov	$0,%ebx
	mov	$__NR_exit,%eax
	int	$0x80