wince 6 s3c2440 io port opearation

1. Decare a IO port
   

   volatile IOPreg     *s2440IOP = (IOPreg *)IOP_BASE;

2. IOPreg and IOP_BASE defined here:s2440.h

   #define IOP_BASE      0xB1600000 // 0x56000000
   typedef struct  {
           unsigned int  rGPACON;            // 00
           unsigned int  rGPADAT;
           unsigned int  rPAD1[2];
       
           unsigned int  rGPBCON;            // 10
           unsigned int  rGPBDAT;
           unsigned int  rGPBUP;
           unsigned int  rPAD2;
       
           unsigned int  rGPCCON;            // 20
           unsigned int  rGPCDAT;
           unsigned int  rGPCUP;
           unsigned int  rPAD3;
       
           unsigned int  rGPDCON;            // 30
           unsigned int  rGPDDAT;
           unsigned int  rGPDUP; 
           unsigned int  rPAD4;
       
           unsigned int  rGPECON;            // 40
           unsigned int  rGPEDAT;
           unsigned int  rGPEUP;
           unsigned int  rPAD5;
       
           unsigned int  rGPFCON;            // 50
           unsigned int  rGPFDAT;
           unsigned int  rGPFUP; 
           unsigned int  rPAD6;
       
           unsigned int  rGPGCON;            // 60
           unsigned int  rGPGDAT;
           unsigned int  rGPGUP; 
           unsigned int  rPAD7;
       
           unsigned int  rGPHCON;            // 70
           unsigned int  rGPHDAT;
           unsigned int  rGPHUP; 
           unsigned int  rPAD8;
       
           unsigned int  rMISCCR;            // 80
           unsigned int  rDCKCON;        
           unsigned int  rEXTINT0;
           unsigned int  rEXTINT1;        
           unsigned int  rEXTINT2;            // 90
           unsigned int  rEINTFLT0;
           unsigned int  rEINTFLT1;
           unsigned int  rEINTFLT2;
           unsigned int  rEINTFLT3;        // A0
           unsigned int  rEINTMASK;
           unsigned int  rEINTPEND;
           unsigned int  rGSTATUS0;        // AC
           unsigned int  rGSTATUS1;        // B0
           unsigned int  rGSTATUS2;        // B4 ;;; SHL
           unsigned int  rGSTATUS3;        // B8
           unsigned int  rGSTATUS4;        // BC
       
           unsigned int  rFLTOUT;            // C0
           unsigned int  rDSC0;
           unsigned int  rDSC1;
           unsigned int  rMSLCON;
   
           unsigned int  rGPJCON;            // D0
           unsigned int  rGPJDAT;
           unsigned int  rGPJUP;
           unsigned int  rPAD9;
       
   }IOPreg;  

3. Operate the IO port like this:

   s2440IOP->rGPBCON  = (s2440IOP->rGPBCON  &~(3 << 10)) | (1<< 10);
   s2440IOP->rGPBDAT=s2440IOP->rGPBDAT&~(0x1<<5);