reduce data type to byte

git-svn-id: svn://svn.code.sf.net/p/pinmame/code/trunk@3617 6f51dfdd-75df-4273-8f3b-818b1e6aa8bf
restore changes, except for the condition and overflow handling for SUB, ADD

..otherwise early zaccarias hang up on start
..thanks to Gaston for noticing

git-svn-id: svn://svn.code.sf.net/p/pinmame/code/trunk@3618 6f51dfdd-75df-4273-8f3b-818b1e6aa8bf