Help to understand device config??

[jjkool]

Please help me to understand this section

unsigned short config = 0;
for(int i=0 ; i<NB_PORT ; i++)
{
if(port_out)
config += (int)pow(2, (i+8));
if(out_mode)
config += (int)pow(2, i);
}
int ok = HardDllCommand(DHC_PORTCONFIG, config, 0);
}