You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
55 lines
1.3 KiB
55 lines
1.3 KiB
#include "soft.h"
|
|
|
|
#define shiftleft(dp,n) { /* n = 0 to 32 */ \
|
|
dp->mant1 = ((dp->mant1 << (n)) + (dp->mant2 >> (32-(n)))) \
|
|
& 0x0FFFFF; dp->mant2 <<= (n); dp->exp -= (n); }
|
|
|
|
|
|
/* Returns fractional part of d, stores integer part in *integ
|
|
*/
|
|
double Modf(double d, double *integ)
|
|
{
|
|
struct bitdouble *dp = (struct bitdouble *)&d;
|
|
struct bitdouble *ip = (struct bitdouble *)integ;
|
|
int e = dp->exp - BIAS;
|
|
|
|
if (e < 0) { /* no integer part */
|
|
*integ = 0;
|
|
return d;
|
|
}
|
|
|
|
/* compute integer: clear fractional part where necessary
|
|
*/
|
|
*integ = d;
|
|
if (e <= 20) {
|
|
ip->mant1 &= (-1L << (20-e)); /* split in mant1... */
|
|
ip->mant2 = 0;
|
|
}
|
|
else
|
|
if (e <= 52)
|
|
ip->mant2 &= (-1L << (52-e)); /* split in mant2 */
|
|
else return 0; /* no fractional part */
|
|
|
|
/* compute fractional part: shift left over integer part
|
|
*/
|
|
if (e)
|
|
if (e <= 32)
|
|
shiftleft(dp,e)
|
|
else {
|
|
dp->mant1 = (dp->mant2 << (e-32)) & 0x0FFFFF;
|
|
dp->mant2 = 0;
|
|
dp->exp -= e;
|
|
}
|
|
|
|
/* adjust fractional part shifting left...
|
|
*/
|
|
if (dp->mant1==0 && dp->mant2==0) /* fraction is zero */
|
|
return 0;
|
|
|
|
while (!(dp->mant1 & 0x080000)) /* stack to the left */
|
|
shiftleft(dp,1);
|
|
|
|
shiftleft(dp,1); /* lose 'invisible bit' */
|
|
return d;
|
|
}
|