float.c

用CS5532做的无线吊钩称的接收称重显示器程序

float float_convert_float(unsigned char *p);
//待输入的数
union
{
	float f;
	unsigned char c[4];
	unsigned long int li;
}floatxx;
//输出的数据
union
{
	float f;
	unsigned char c[4];
	unsigned long int li;
}floatyy;
//接受到的数组
/*unsigned	char	in_array[4] = {0x40,0x00,0x00,0xee};
unsigned	long	in_li;//接收到数组的排列的长整数*/
	

/*void	main(void)
{
	unsigned	long	li_out;
	floatxx.c[0] = in_array[0];
	floatxx.c[1] = in_array[1];
	floatxx.c[2] = in_array[2];
	floatxx.c[3] = in_array[3];
	in_li = floatxx.li;
	li_out = (unsigned long)float_convert_float(in_li);
}*/

//浮点数转化为浮点数，返回浮点数

float float_convert_float(unsigned char *p)
{
	unsigned char c;
	floatxx.c[0] = *p;
	floatxx.c[1] = *(p+1);
	floatxx.c[2] = *(p+2);
	floatxx.c[3] = *(p+3);
	if (floatxx.li == 0) return (0);

	c = floatxx.c[3] - 0xea;
	c = c + 127;
	
	floatyy.c[3] = floatxx.c[2];
	floatyy.c[2] = floatxx.c[1];
	floatyy.c[1] = floatxx.c[0];
	floatyy.li = floatyy.li << 1;

	floatyy.c[1] = floatyy.c[1] & 0x7f;
	if ( (c&0x1) == 1 ) floatyy.c[1] = floatyy.c[1] | 0x80;
	floatyy.c[0] = c >> 1;
	floatyy.c[0] &= 0x7f;
	
	if((floatxx.c[0]&0x80) == 0x80) 
	{
		floatyy.c[0] |= 0x80;
	}
	return( floatyy.f );
}