98 lines
2.6 KiB
C
98 lines
2.6 KiB
C
/* _LDnorm function -- IEEE 754 version */
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#include "wctype.h"
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#include "xmath.h"
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_STD_BEGIN
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#if !_DLONG
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/* not needed */
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#elif _LONG_DOUBLE_HAS_HIDDEN_BIT
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_CRTIMP2 short _LDnorm(unsigned short *ps)
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{ /* normalize long double fraction -- SPARC */
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short xchar;
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unsigned short sign = ps[_L0];
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xchar = 1;
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if (ps[_L1] != 0 || ps[_L2] != 0 || ps[_L3] != 0
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|| ps[_L4] != 0 || ps[_L5] != 0 || ps[_L6] != 0
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|| ps[_L7] != 0)
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{ /* nonzero, scale */
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for (ps[_L0] = 0; ps[_L0] == 0 && ps[_L1] < 0x100;
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xchar -= 16)
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{ /* shift left by 16 */
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ps[_L0] = ps[_L1];
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ps[_L1] = ps[_L2], ps[_L2] = ps[_L3];
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ps[_L3] = ps[_L4], ps[_L4] = ps[_L5];
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ps[_L5] = ps[_L6], ps[_L6] = ps[_L7];
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ps[_L7] = 0;
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}
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for (; ps[_L0] == 0; --xchar)
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{ /* shift left by 1 */
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ps[_L0] = ps[_L0] << 1 | ps[_L1] >> 15;
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ps[_L1] = ps[_L1] << 1 | ps[_L2] >> 15;
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ps[_L2] = ps[_L2] << 1 | ps[_L3] >> 15;
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ps[_L3] = ps[_L3] << 1 | ps[_L4] >> 15;
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ps[_L4] = ps[_L4] << 1 | ps[_L5] >> 15;
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ps[_L5] = ps[_L5] << 1 | ps[_L6] >> 15;
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ps[_L6] = ps[_L6] << 1 | ps[_L7] >> 15;
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ps[_L7] <<= 1;
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}
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for (; 1 < ps[_L0]; ++xchar)
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{ /* shift right by 1 */
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ps[_L7] = ps[_L7] >> 1 | ps[_L6] << 15;
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ps[_L6] = ps[_L6] >> 1 | ps[_L5] << 15;
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ps[_L5] = ps[_L5] >> 1 | ps[_L4] << 15;
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ps[_L4] = ps[_L4] >> 1 | ps[_L3] << 15;
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ps[_L3] = ps[_L3] >> 1 | ps[_L2] << 15;
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ps[_L2] = ps[_L2] >> 1 | ps[_L1] << 15;
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ps[_L1] = ps[_L1] >> 1 | ps[_L0] << 15;
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ps[_L0] >>= 1;
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}
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}
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ps[_L0] = sign;
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return (xchar);
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}
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#else /* !_LONG_DOUBLE_HAS_HIDDEN_BIT */
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_CRTIMP2 short _LDnorm(unsigned short *ps)
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{ /* normalize long double fraction */
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short xchar;
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unsigned short sign = ps[_L0];
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xchar = 0;
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for (ps[_L0] = 0; ps[_L0] == 0 && ps[_L1] < 0x100;
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xchar -= 16)
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{ /* shift left by 16 */
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ps[_L0] = ps[_L1];
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ps[_L1] = ps[_L2], ps[_L2] = ps[_L3];
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ps[_L3] = ps[_L4], ps[_L4] = 0;
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}
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if (ps[_L0] == 0)
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for (; ps[_L1] < (1U << _LOFF); --xchar)
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{ /* shift left by 1 */
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ps[_L1] = ps[_L1] << 1 | ps[_L2] >> 15;
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ps[_L2] = ps[_L2] << 1 | ps[_L3] >> 15;
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ps[_L3] = ps[_L3] << 1 | ps[_L4] >> 15;
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ps[_L4] <<= 1;
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}
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for (; ps[_L0] != 0; ++xchar)
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{ /* shift right by 1 */
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ps[_L4] = ps[_L4] >> 1 | ps[_L3] << 15;
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ps[_L3] = ps[_L3] >> 1 | ps[_L2] << 15;
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ps[_L2] = ps[_L2] >> 1 | ps[_L1] << 15;
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ps[_L1] = ps[_L1] >> 1 | ps[_L0] << 15;
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ps[_L0] >>= 1;
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}
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ps[_L0] = sign;
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return (xchar);
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}
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#endif
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_STD_END
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/*
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* Copyright (c) 1994 by P.J. Plauger. ALL RIGHTS RESERVED.
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* Consult your license regarding permissions and restrictions.
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*/
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/*
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941029 pjp: added _STD machinery
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*/
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