version 1.1.1.2, 2000/09/09 14:12:52 |
version 1.1.1.3, 2003/08/25 16:06:33 |
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/* double mpz_get_d (mpz_t src) -- Return the double approximation to SRC. |
/* double mpz_get_d (mpz_t src) -- Return the double approximation to SRC. |
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Copyright (C) 1996, 1997, 2000 Free Software Foundation, Inc. |
Copyright 1996, 1997, 2000, 2001, 2002 Free Software Foundation, Inc. |
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This file is part of the GNU MP Library. |
This file is part of the GNU MP Library. |
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Line 24 MA 02111-1307, USA. */ |
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Line 24 MA 02111-1307, USA. */ |
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#include "longlong.h" |
#include "longlong.h" |
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static int |
/* FIXME: Would prefer to inline this on all compilers, not just those with |
#if __STDC__ |
"inline". */ |
mpn_zero_p (mp_ptr p, mp_size_t n) |
static inline int |
#else |
mpn_zero_p (mp_srcptr p, mp_size_t n) |
mpn_zero_p (p, n) |
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mp_ptr p; |
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mp_size_t n; |
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#endif |
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{ |
{ |
mp_size_t i; |
mp_size_t i; |
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for (i = 0; i < n; i++) |
for (i = 0; i < n; i++) |
{ |
if (p[i] != 0) |
if (p[i] != 0) |
return 0; |
return 0; |
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} |
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return 1; |
return 1; |
} |
} |
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double |
double |
#if __STDC__ |
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mpz_get_d (mpz_srcptr src) |
mpz_get_d (mpz_srcptr src) |
#else |
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mpz_get_d (src) |
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mpz_srcptr src; |
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#endif |
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{ |
{ |
double res; |
double res; |
mp_size_t size; |
mp_size_t size; |
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else |
else |
{ |
{ |
count_leading_zeros (cnt, qp[size - 1]); |
count_leading_zeros (cnt, qp[size - 1]); |
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cnt -= GMP_NAIL_BITS; |
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#if BITS_PER_MP_LIMB == 32 |
#if BITS_PER_MP_LIMB == 32 |
if (cnt == 0) |
if (cnt == 0) |
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} |
} |
else |
else |
{ |
{ |
hz = (qp[size - 1] << cnt) | (qp[size - 2] >> BITS_PER_MP_LIMB - cnt); |
hz = ((qp[size - 1] << cnt) | (qp[size - 2] >> GMP_NUMB_BITS - cnt)) & GMP_NUMB_MASK; |
lz = (qp[size - 2] << cnt) | (qp[size - 3] >> BITS_PER_MP_LIMB - cnt); |
lz = ((qp[size - 2] << cnt) | (qp[size - 3] >> GMP_NUMB_BITS - cnt)) & GMP_NUMB_MASK; |
} |
} |
#if _GMP_IEEE_FLOATS |
#if _GMP_IEEE_FLOATS |
/* Take bits from less significant limbs, but only if they may affect |
/* Take bits from less significant limbs, but only if they may affect |
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if ((lz & 0x7ff) == 0x400) |
if ((lz & 0x7ff) == 0x400) |
{ |
{ |
if (cnt != 0) |
if (cnt != 0) |
lz += ((qp[size - 3] << cnt) != 0 || ! mpn_zero_p (qp, size - 3)); |
lz += (((qp[size - 3] << cnt) & GMP_NUMB_MASK) != 0 |
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|| ! mpn_zero_p (qp, size - 3)); |
else |
else |
lz += (! mpn_zero_p (qp, size - 2)); |
lz += (! mpn_zero_p (qp, size - 2)); |
} |
} |
#endif |
#endif |
res = MP_BASE_AS_DOUBLE * hz + lz; |
res = MP_BASE_AS_DOUBLE * hz + lz; |
res = __gmp_scale2 (res, (size - 2) * BITS_PER_MP_LIMB - cnt); |
res = __gmp_scale2 (res, (size - 2) * GMP_NUMB_BITS - cnt); |
#endif |
#endif |
#if BITS_PER_MP_LIMB == 64 |
#if BITS_PER_MP_LIMB == 64 |
if (cnt == 0) |
if (cnt == 0) |
hz = qp[size - 1]; |
hz = qp[size - 1]; |
else |
else |
hz = (qp[size - 1] << cnt) | (qp[size - 2] >> BITS_PER_MP_LIMB - cnt); |
hz = ((qp[size - 1] << cnt) | (qp[size - 2] >> GMP_NUMB_BITS - cnt)) & GMP_NUMB_MASK; |
#if _GMP_IEEE_FLOATS |
#if _GMP_IEEE_FLOATS |
if ((hz & 0x7ff) == 0x400) |
if ((hz & 0x7ff) == 0x400) |
{ |
{ |
if (cnt != 0) |
if (cnt != 0) |
hz += ((qp[size - 2] << cnt) != 0 || ! mpn_zero_p (qp, size - 2)); |
hz += (((qp[size - 2] << cnt) & GMP_NUMB_MASK) != 0 |
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|| ! mpn_zero_p (qp, size - 2)); |
else |
else |
hz += (! mpn_zero_p (qp, size - 1)); |
hz += (! mpn_zero_p (qp, size - 1)); |
} |
} |
#endif |
#endif |
res = hz; |
res = hz; |
res = __gmp_scale2 (res, (size - 1) * BITS_PER_MP_LIMB - cnt); |
res = __gmp_scale2 (res, (size - 1) * GMP_NUMB_BITS - cnt); |
#endif |
#endif |
} |
} |
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