implement undocumented flags modifications for BCD instructions
implement undocumented flags modifications for BCD instructions

dariaphoebe/bochs,dariaphoebe/bochs,dariaphoebe/bochs,dbrashear/bochs,dbrashear/bochs,dariaphoebe/bochs,dariaphoebe/bochs,dbrashear/bochs,dbrashear/bochs,dbrashear/bochs