49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
/* _Dnorm function -- IEEE 754 version */
|
|
#include "wctype.h"
|
|
#include "xmath.h"
|
|
_STD_BEGIN
|
|
|
|
_CRTIMP2 short _Dnorm(unsigned short *ps)
|
|
{ /* normalize double fraction */
|
|
short xchar;
|
|
unsigned short sign = ps[_D0] & _DSIGN;
|
|
|
|
xchar = 1;
|
|
if ((ps[_D0] &= _DFRAC) != 0 || ps[_D1]
|
|
|| ps[_D2] || ps[_D3])
|
|
{ /* nonzero, scale */
|
|
for (; ps[_D0] == 0; xchar -= 16)
|
|
{ /* shift left by 16 */
|
|
ps[_D0] = ps[_D1], ps[_D1] = ps[_D2];
|
|
ps[_D2] = ps[_D3], ps[_D3] = 0;
|
|
}
|
|
for (; ps[_D0] < 1<<_DOFF; --xchar)
|
|
{ /* shift left by 1 */
|
|
ps[_D0] = ps[_D0] << 1 | ps[_D1] >> 15;
|
|
ps[_D1] = ps[_D1] << 1 | ps[_D2] >> 15;
|
|
ps[_D2] = ps[_D2] << 1 | ps[_D3] >> 15;
|
|
ps[_D3] <<= 1;
|
|
}
|
|
for (; 1<<(_DOFF+1) <= ps[_D0]; ++xchar)
|
|
{ /* shift right by 1 */
|
|
ps[_D3] = ps[_D3] >> 1 | ps[_D2] << 15;
|
|
ps[_D2] = ps[_D2] >> 1 | ps[_D1] << 15;
|
|
ps[_D1] = ps[_D1] >> 1 | ps[_D0] << 15;
|
|
ps[_D0] >>= 1;
|
|
}
|
|
ps[_D0] &= _DFRAC;
|
|
}
|
|
ps[_D0] |= sign;
|
|
return (xchar);
|
|
}
|
|
_STD_END
|
|
|
|
/*
|
|
* Copyright (c) 1994 by P.J. Plauger. ALL RIGHTS RESERVED.
|
|
* Consult your license regarding permissions and restrictions.
|
|
*/
|
|
|
|
/*
|
|
941029 pjp: added _STD machinery
|
|
*/
|