fix registers may not be the same -- strexb r0,r0,[r1]
fix overlaps section
Merge pull request #4 from yyken/master

fix overlaps section
Debug itoa(): Output is incorrect when passing negative number
Merge pull request #6 from LanKuDot/debug_itoa

Fix itoa: output is incorrect when passing negative number
Merge remote-tracking branch 'embedded/master'

Conflicts:
	kernel.c