ossp-pkg/xds/float2xds-float.c
1.1
#include "xds_p.h"
int float2xds_float(xds_float_t* new_num, float num)
{
const static unsigned int base = 2;
size_t i;
float tmp;
/* Handle zero as a special case. */
if (num == 0.0)
{
new_num->sign = 0;
new_num->fraction = 0;
new_num->exponent = -127;
return 0;
}
/* Determine the sign of the number. */
if (num < 0)
{
new_num->sign = 1;
num = 0 - num;
}
else
new_num->sign = 0;
/* Canonify the number before we convert it. */
new_num->exponent = 0;
while (num < 1)
{
num *= base;
--new_num->exponent;
}
/* Find the exponent. */
for (i = 0, tmp = 1; i <= 128; ++i, tmp *= base)
{
if (tmp*base > num)
break;
}
if (i <= 128)
{
num = num / tmp - 1;
new_num->exponent += i;
}
else
return 1;
/* Calculate the fraction part. */
for (new_num->fraction = 0, i = 0; i < 23; ++i)
{
new_num->fraction *= base;
if (num >= 1.0 / base)
{
new_num->fraction |= 1;
num = num * base - 1;
}
else
{
new_num->fraction |= 0;
num *= base;
}
}
return 0;
}
