rem: SetSemaphore (&GraphicsSem);
add: SetSemaphore (GraphicsSem);
context: DeltaCredit (SIZE delta_credit){	COUNT Credit;	Credit = MAKE_WORD (			GET_GAME_STATE (MELNORME_CREDIT0),			GET_GAME_STATE (MELNORME_CREDIT1)			);	if ((int)delta_credit >= 0 || ((int)(-delta_credit) <= (int)(Credit)))	{		Credit += delta_credit;		SET_GAME_STATE (MELNORME_CREDIT0, LOBYTE (Credit));		SET_GAME_STATE (MELNORME_CREDIT1, HIBYTE (Credit));		SetSemaphore (&GraphicsSem);		DrawStatusMessage ((UNICODE *)~0);		ClearSemaphore (&GraphicsSem);	}	else	{		NPCPhrase (NEED_MORE_CREDIT0);		NPCPhrase (delta_credit);		NPCPhrase (NEED_MORE_CREDIT1);	}		return (Credit);}