F28069 GPIOs simulate 16bit EMIF

Dears,

Do you have a sample code which used GPIOs simulate 16bit EMIF? Or could you please advise how to improve the simulate EMIF R/W speed? thanks a lot! 

According to the datasheet, GPIO toggling frequency is 22.5MHz. unfortunately, It takes me 102 CPU cycles for a 16bit data read and write cycle by using below codes. Could you advise how to improve the efficiency? 

#define DATA_EN_H  GpioDataRegs.GPADAT.all |= 0x01000000 
#define DATA_EN_L  GpioDataRegs.GPADAT.all &= 0xfeffffff 

#define DATA_CLK_H GpioDataRegs.GPADAT.all |= 0x00800000 
#define DATA_CLK_L GpioDataRegs.GPADAT.all &= 0xFF7FFFFF 

	for(i=0;i<len;i++)
	{
		//setup data
		tmp= ( ((Uint32)(*(pdata_in+i))&0xf000)<<6 ) +  (((Uint32)(*(pdata_in+i))&0x0fff)<<4);
		GpioDataRegs.GPADAT.all &= 0xffc3000f;     //clear 16bit data;
		GpioDataRegs.GPADAT.all |= tmp ;           //set   16bit data;

		//HOLD CLK HIGH
		DATA_CLK_H;                            // clk high ;
		GpioCtrlRegs.GPADIR.all &= 0xffc3000f; // dir=input

		//HOLD CLK LOW
		DATA_CLK_L;                            // clk low;

		//read data
		tmp=GpioDataRegs.GPADAT.all;
		*(pdata_out+i)= ( (tmp>>6) & 0xf000) + ((tmp & 0x0ffff) >> 4);
		// dir=output
		GpioCtrlRegs.GPADIR.all |= 0x003cfff0;
	}