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if(fpointer<0)

{

fpointer=fpointer*(-1);

Flag=1;

}

decimal = modf(fpointer,&integer);   //将整数位到存到 integer ，小数位返回到decimal

if(decimal || integer)    //判断 fpointer是否为0

{

bindecimal = (unsigned  long )(decimal * 0x800000);   //0x800000=2^23 。得到小数位二进制表现形式

while((bindecimal & 0xff800000) > 0) //计算有没有超过23位二进制数

bindecimal >>= 1;

if(integer > 0)

{

bininteger = (unsigned  long )integer;

for(i=0;i<32;i++)               //计算整数部分的2的幂指数，整数位转化为二进制后的位数，计算小数点移动的位数

{

if(bininteger&0x1)

_power = i;

bininteger >>= 0x1;

}

bininteger = (unsigned  long )integer;

bininteger &= ~(0x1 << _power); //去掉最高位的1

if(_power >= 23) //如果幂指数>23 则舍弃小数位部分

{

bininteger >>= (_power-23);

bindecimal = 127+_power;

bininteger |= bindecimal << 23;

}

else

{

bininteger <<= (23 – _power);//将去掉最高位的整数二进制，移至第22为

bindecimal >>= _power;       //将小数部分左移1，

bininteger |= bindecimal;    //二者向或得到1.x的x，

bindecimal = 127+_power;     //指数，右移的小数点数+127

bininteger |= bindecimal << 23; // 指数为右移23为变为或上x。

}

}

else if(integer == 0)

{

bindecimal <<= 9; //将小数部分的二进制移至最高位31位

_power = 0;

bininteger = bindecimal;

while(bininteger == ((bindecimal<<1)>>1)) //判断小数位最高位是否为1.  最高位为0 ：真

{

_power++;

bindecimal <<= 0x1;

bininteger = bindecimal;  //直到最高位为1,退出循环

}

_power++;

bindecimal <<= 0x1;    //将1.x的1去掉 求x的值，

bindecimal >>= 9;      //将小数位回到0-22位

bininteger = bindecimal; //暂存到二进制整数中，

bindecimal = 127-_power;

bininteger |= bindecimal << 23;  //将指数为右移值23为向或得到其值，

}

if(Flag==1)

bininteger |= 0x80000000;

i = 0;

a[i++] =(unsigned char) ((bininteger >> 24) & 0xff);

a[i++] = (unsigned char)((bininteger >> 16) & 0xff);

a[i++] = (unsigned char)((bininteger >> 8 ) & 0xff);

a[i++] =(unsigned char)( bininteger & 0xff);

}

}

float ConvertIEE754ToDex(unsigned char *SpModRegister)

{

float x,fpointer;

unsigned long bininteger,bintmp;

int _power,i=0,s;

bintmp = SpModRegister[i++] << 8;

bintmp |= SpModRegister[i++];

bininteger = SpModRegister[i++] << 8;

bininteger |= SpModRegister[i++];

bininteger |= bintmp << 16;

if(bininteger == 0)

return 0.0;

bintmp = bininteger & 0x7FFFFF;

x = (double)bintmp / 0x800000;

bintmp = bininteger >> 23;

_power = bintmp & 0xff;

bintmp = bininteger & 0x80000000;

s = (bintmp) ? 1 : 0 ;

bintmp =(unsigned  long ) pow(2,fabs(_power-127)) ;

if(_power >= 127)

fpointer = (1+x) * bintmp ;

else

fpointer = (1+x) / bintmp ;

//bintmp = (fpointer * 10000 + 5)/10;

//fpointer = (double)bintmp / 1000;

if(s)

fpointer *= -1;

return (fpointer);

}