How to write directly to a GPIO Register

 I need to directly make a GPIO pin low to High within 50 nano second

when i use API

{

g_ioport.p_api->pinWrite(IOPORT_PORT_03_PIN_02,IOPORT_LEVEL_LOW);

}

It takes 1.5 micro seconds which is a huge time for my requirement 

i have configured the TB-S1JA to operate at 48 Mhz so that i should be able to achieve 21 nano second but that is not happening 

How to toggle a GPIO with only one instruction?

 

 

Thanks

Krupashankar