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Tricks of the Windows Gam…ming Gurus (2nd Edition)
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Disc2.iso
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vc98
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crt
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src
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xfdnorm.c
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C/C++ Source or Header
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1998-06-16
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927b
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41 lines
/* _FDnorm function -- IEEE 754 version */
#include "wctype.h"
#include "xmath.h"
_STD_BEGIN
_CRTIMP2 short _FDnorm(unsigned short *ps)
{ /* normalize float fraction */
short xchar;
unsigned short sign = ps[_F0] & _FSIGN;
xchar = 1;
if ((ps[_F0] &= _FFRAC) != 0 || ps[_F1])
{ /* nonzero, scale */
if (ps[_F0] == 0)
ps[_F0] = ps[_F1], ps[_F1] = 0, xchar -= 16;
for (; ps[_F0] < 1<<_FOFF; --xchar)
{ /* shift left by 1 */
ps[_F0] = ps[_F0] << 1 | ps[_F1] >> 15;
ps[_F1] <<= 1;
}
for (; 1<<_FOFF+1 <= ps[_F0]; ++xchar)
{ /* shift right by 1 */
ps[_F1] = ps[_F1] >> 1 | ps[_F0] << 15;
ps[_F0] >>= 1;
}
ps[_F0] &= _FFRAC;
}
ps[_F0] |= 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
*/