Elaborate and add details
Installing packages on Gentoo is as easy as on any Linux platform.
emerge -av gputils
For now, version 2.5 of SDCC is officialy supported so add the corresponding rule in one of your /etc/portage/packages.keywords files and emerge sdcc.
cat '=dev-embedded/sdcc-2.5*' >> /etc/portage/packages.keywords/mios emerge -av sdcc