ARM板按键控制蜂鸣器实验求救

#define rGPBCON (*(volatile unsigned*)0x56000010)
#define rGPBDAT (*(volatile unsigned*)0X56000014)
#define rGPBUP (*(volatile unsigned*)0X56000018)
#define rGPGCON (*(volatile unsigned*)0x56000060)
#define rGPGDAT (*(volatile unsigned*)0X56000064)
#define rGPGUP (*(volatile unsigned*)0X56000068)
void Delay(int n)
{
int i, j;
for(i=0; i<n; i++)
for(j=0; j< 1000000; j++)
j = j + 0;
}
int Main(void)
{
rGPGUP=0XFFFF;
rGPBUP=0XFFF;
rGPGCON=0XFF3F033C;
rGPBCON=0XFFFFFD;
while(1)
{
int k;
k=rGPGDAT;
k&=0XF716;
if(k==0XFFFE)
{
rGPGDAT=0XFFF;
Delay(10);
rGPGDAT=0XFFE;
Delay(10);
}
else if(k==0XFFF7)
{
rGPGDAT=0XFFF;
Delay(10);
rGPGDAT=0XFFE;
Delay(10);
}
else if(k==0XFFDE)
{ rGPGDAT=0XFFF;
Delay(10);
rGPGDAT=0XFFE;
Delay(10);
}
else if(k==0XFFBE)
{ rGPGDAT=0XFFF;
Delay(10);
rGPGDAT=0XFFE;
Delay(10);
}
else if(k==0XFF7E)
{
rGPGDAT=0XFFF;
Delay(10);
rGPGDAT=0XFFE;
Delay(10);
}
else if (k==0XF7FE)
{
rGPGDAT=0XFFF;
Delay(10);
rGPGDAT=0XFFE;
Delay(10);
}
else
continue;
}

汇编能实现，但C语言执行过程有问题