[arm] implement mul, stm1, various fixes
[arm] implement mul, stm1, various fixes

moreati/pydgin,cornell-brg/pydgin,cornell-brg/pydgin,futurecore/pydgin,moreati/pydgin,futurecore/pydgin,cornell-brg/pydgin,moreati/pydgin,futurecore/pydgin,cornell-brg/pydgin,futurecore/pydgin,moreati/pydgin