在WINCE下能够直接访问的都是虚拟地址，不能直接访问GPIO端口，因此我们首先需要将GPIO口的物理地址映射到虚拟地址上来。 
    分别使用VirtualAlloc和VirtualCopy这两个函数来完成映射！ 
这两个函数的原型： 
LPVOID VirtualAlloc(      LPVOID lpAddress,        DWORD dwSize, 
DWORD flAllocationType,    DWORD flProtect ); 
BOOL VirtualCopy( LPVOID lpvDest, LPVOID lpvSrc, DWORD cbSize, DWORD fdwProtect ); 
如果这两个函数执行成功，哪么VirtualAlloc将返回一个指针，使用这个指针我们就可以直接访问GPIO，通过读写相关地址寄存器，来控制GPIO端口！ 
   v_pIOPregs = (volatile IOPreg *)VirtualAlloc(0, sizeof(IOPreg), MEM_RESERVE, PAGE_NOACCESS); 
          if (v_pIOPregs == NULL){ 
                    RetValue = FALSE; 
          } 
          else { 
                    if (!VirtualCopy((PVOID)v_pIOPregs, (PVOID)(IOP_BASE), sizeof(IOPreg), PAGE_READWRITE | PAGE_NOCACHE)) { 
                             RetValue = FALSE; 
                    } 
          } 
          if (!RetValue){ 
                    //PIO_InitializeAddresses - Failed !! 
          if (v_pIOPregs){ 
                             VirtualFree((PVOID) v_pIOPregs, 0, MEM_RELEASE); 
                    } 
                    v_pIOPregs = NULL; 
          } 
          //else RETAILMSG (1, (TEXT("::: PBT_InitializeAddresses - Success\r\n") )); 
          return(RetValue); 
v_pIOPregs是一个IOPreg结构，在s2410.h中定义， 
// 
// Registers : I/O port 
#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; 
          unsigned int   rGSTATUS1;                 // B0 
}IOPreg;