int
mpfr_set_si (mpfr_ptr x, long i, mp_rnd_t rnd_mode)
{
int inex;
mp_size_t xn;
unsigned int cnt, nbits;
mp_limb_t ai, *xp;
MPFR_CLEAR_FLAGS(x);
if (i == 0)
{
MPFR_SET_ZERO(x);
MPFR_SET_POS(x);
MPFR_RET(0);
}
xn = (MPFR_PREC(x)-1)/BITS_PER_MP_LIMB;
ai = SAFE_ABS(long, i);
count_leading_zeros(cnt, ai);
xp = MPFR_MANT(x);
xp[xn] = ai << cnt;
/* don't forget to put zero in lower limbs */
MPN_ZERO(xp, xn);
/* set sign */
if ((i < 0) ^ (MPFR_SIGN(x) < 0))
MPFR_CHANGE_SIGN(x);
MPFR_EXP(x) = nbits = BITS_PER_MP_LIMB - cnt;
inex = mpfr_check_range(x, rnd_mode);
if (inex)
return inex; /* underflow or overflow */
/* round if MPFR_PREC(x) smaller than length of i */
if (MPFR_PREC(x) < nbits)
{
int carry;
carry = mpfr_round_raw(xp+xn, xp+xn, nbits, (i < 0), MPFR_PREC(x),
rnd_mode, &inex);
if (carry)
{
mp_exp_t exp = MPFR_EXP(x);
if (exp == __mpfr_emax)
return mpfr_set_overflow(x, rnd_mode, (i < 0 ? -1 : 1));
MPFR_EXP(x)++;
xp[xn] = GMP_LIMB_HIGHBIT;
}
}
MPFR_RET(inex);
}
int
mpfr_set_si_2exp (mpfr_ptr x, long i, mp_exp_t e, mp_rnd_t rnd_mode)
{
if (i == 0)
{
MPFR_SET_ZERO (x);
MPFR_SET_POS (x);
MPFR_RET (0);
}
else
{
mp_size_t xn;
unsigned int cnt, nbits;
mp_limb_t ai, *xp;
int inex = 0;
/* FIXME: support int limbs (e.g. 16-bit limbs on 16-bit proc) */
ai = SAFE_ABS (unsigned long, i);
MPFR_ASSERTN (SAFE_ABS (unsigned long, i) == ai);
/* Position of the highest limb */
xn = (MPFR_PREC (x) - 1) / BITS_PER_MP_LIMB;
count_leading_zeros (cnt, ai);
MPFR_ASSERTD (cnt < BITS_PER_MP_LIMB); /* OK since i != 0 */
xp = MPFR_MANT(x);
xp[xn] = ai << cnt;
/* Zero the xn lower limbs. */
MPN_ZERO(xp, xn);
MPFR_SET_SIGN (x, i < 0 ? MPFR_SIGN_NEG : MPFR_SIGN_POS);
nbits = BITS_PER_MP_LIMB - cnt;
e += nbits; /* exponent _before_ the rounding */
/* round if MPFR_PREC(x) smaller than length of i */
if (MPFR_UNLIKELY (MPFR_PREC (x) < nbits) &&
MPFR_UNLIKELY (mpfr_round_raw (xp + xn, xp + xn, nbits, i < 0,
MPFR_PREC (x), rnd_mode, &inex)))
{
e++;
xp[xn] = MPFR_LIMB_HIGHBIT;
}
MPFR_CLEAR_FLAGS (x);
MPFR_EXP (x) = e;
return mpfr_check_range (x, inex, rnd_mode);
}
}
int
mpfr_set_ui_2exp (mpfr_ptr x, unsigned long i, mpfr_exp_t e, mpfr_rnd_t rnd_mode)
{
MPFR_SET_POS (x);
if (i == 0)
{
MPFR_SET_ZERO (x);
MPFR_RET (0);
}
else
{
mp_size_t xn;
unsigned int cnt, nbits;
mp_limb_t *xp;
int inex = 0;
/* FIXME: support int limbs (e.g. 16-bit limbs on 16-bit proc) */
MPFR_ASSERTD (i == (mp_limb_t) i);
/* Position of the highest limb */
xn = (MPFR_PREC (x) - 1) / GMP_NUMB_BITS;
count_leading_zeros (cnt, (mp_limb_t) i);
MPFR_ASSERTD (cnt < GMP_NUMB_BITS); /* OK since i != 0 */
xp = MPFR_MANT(x);
xp[xn] = ((mp_limb_t) i) << cnt;
/* Zero the xn lower limbs. */
MPN_ZERO(xp, xn);
nbits = GMP_NUMB_BITS - cnt;
e += nbits; /* exponent _before_ the rounding */
/* round if MPFR_PREC(x) smaller than length of i */
if (MPFR_UNLIKELY (MPFR_PREC (x) < nbits) &&
MPFR_UNLIKELY (mpfr_round_raw (xp + xn, xp + xn, nbits, 0,
MPFR_PREC (x), rnd_mode, &inex)))
{
e++;
xp[xn] = MPFR_LIMB_HIGHBIT;
}
MPFR_EXP (x) = e;
return mpfr_check_range (x, inex, rnd_mode);
}
}
int
mpfr_sqr (mpfr_ptr a, mpfr_srcptr b, mpfr_rnd_t rnd_mode)
{
int cc, inexact;
mpfr_exp_t ax;
mp_limb_t *tmp;
mp_limb_t b1;
mpfr_prec_t bq;
mp_size_t bn, tn;
MPFR_TMP_DECL(marker);
MPFR_LOG_FUNC (("x[%#R]=%R rnd=%d", b, b, rnd_mode),
("y[%#R]=%R inexact=%d", a, a, inexact));
/* deal with special cases */
if (MPFR_UNLIKELY(MPFR_IS_SINGULAR(b)))
{
if (MPFR_IS_NAN(b))
{
MPFR_SET_NAN(a);
MPFR_RET_NAN;
}
MPFR_SET_POS (a);
if (MPFR_IS_INF(b))
MPFR_SET_INF(a);
else
( MPFR_ASSERTD(MPFR_IS_ZERO(b)), MPFR_SET_ZERO(a) );
MPFR_RET(0);
}
ax = 2 * MPFR_GET_EXP (b);
bq = MPFR_PREC(b);
MPFR_ASSERTD (2 * bq > bq); /* PREC_MAX is /2 so no integer overflow */
bn = MPFR_LIMB_SIZE(b); /* number of limbs of b */
tn = 1 + (2 * bq - 1) / GMP_NUMB_BITS; /* number of limbs of square,
2*bn or 2*bn-1 */
MPFR_TMP_MARK(marker);
tmp = (mp_limb_t *) MPFR_TMP_ALLOC((size_t) 2 * bn * BYTES_PER_MP_LIMB);
/* Multiplies the mantissa in temporary allocated space */
mpn_sqr_n (tmp, MPFR_MANT(b), bn);
b1 = tmp[2 * bn - 1];
/* now tmp[0]..tmp[2*bn-1] contains the product of both mantissa,
with tmp[2*bn-1]>=2^(GMP_NUMB_BITS-2) */
b1 >>= GMP_NUMB_BITS - 1; /* msb from the product */
/* if the mantissas of b and c are uniformly distributed in ]1/2, 1],
then their product is in ]1/4, 1/2] with probability 2*ln(2)-1 ~ 0.386
and in [1/2, 1] with probability 2-2*ln(2) ~ 0.614 */
tmp += 2 * bn - tn; /* +0 or +1 */
if (MPFR_UNLIKELY(b1 == 0))
mpn_lshift (tmp, tmp, tn, 1); /* tn <= k, so no stack corruption */
cc = mpfr_round_raw (MPFR_MANT (a), tmp, 2 * bq, 0,
MPFR_PREC (a), rnd_mode, &inexact);
/* cc = 1 ==> result is a power of two */
if (MPFR_UNLIKELY(cc))
MPFR_MANT(a)[MPFR_LIMB_SIZE(a)-1] = MPFR_LIMB_HIGHBIT;
MPFR_TMP_FREE(marker);
{
mpfr_exp_t ax2 = ax + (mpfr_exp_t) (b1 - 1 + cc);
if (MPFR_UNLIKELY( ax2 > __gmpfr_emax))
return mpfr_overflow (a, rnd_mode, MPFR_SIGN_POS);
if (MPFR_UNLIKELY( ax2 < __gmpfr_emin))
{
/* In the rounding to the nearest mode, if the exponent of the exact
result (i.e. before rounding, i.e. without taking cc into account)
is < __gmpfr_emin - 1 or the exact result is a power of 2 (i.e. if
both arguments are powers of 2), then round to zero. */
if (rnd_mode == MPFR_RNDN &&
(ax + (mpfr_exp_t) b1 < __gmpfr_emin || mpfr_powerof2_raw (b)))
rnd_mode = MPFR_RNDZ;
return mpfr_underflow (a, rnd_mode, MPFR_SIGN_POS);
}
MPFR_SET_EXP (a, ax2);
MPFR_SET_POS (a);
}
MPFR_RET (inexact);
}
static int
mpfr_mul3 (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t rnd_mode)
{
/* Old implementation */
int sign_product, cc, inexact;
mpfr_exp_t ax;
mp_limb_t *tmp;
mp_limb_t b1;
mpfr_prec_t bq, cq;
mp_size_t bn, cn, tn, k;
MPFR_TMP_DECL(marker);
/* deal with special cases */
if (MPFR_ARE_SINGULAR(b,c))
{
if (MPFR_IS_NAN(b) || MPFR_IS_NAN(c))
{
MPFR_SET_NAN(a);
MPFR_RET_NAN;
}
sign_product = MPFR_MULT_SIGN( MPFR_SIGN(b) , MPFR_SIGN(c) );
if (MPFR_IS_INF(b))
{
if (MPFR_IS_INF(c) || MPFR_NOTZERO(c))
{
MPFR_SET_SIGN(a,sign_product);
MPFR_SET_INF(a);
MPFR_RET(0); /* exact */
}
else
{
MPFR_SET_NAN(a);
MPFR_RET_NAN;
}
}
else if (MPFR_IS_INF(c))
{
if (MPFR_NOTZERO(b))
{
MPFR_SET_SIGN(a, sign_product);
MPFR_SET_INF(a);
MPFR_RET(0); /* exact */
}
else
{
MPFR_SET_NAN(a);
MPFR_RET_NAN;
}
}
else
{
MPFR_ASSERTD(MPFR_IS_ZERO(b) || MPFR_IS_ZERO(c));
MPFR_SET_SIGN(a, sign_product);
MPFR_SET_ZERO(a);
MPFR_RET(0); /* 0 * 0 is exact */
}
}
sign_product = MPFR_MULT_SIGN( MPFR_SIGN(b) , MPFR_SIGN(c) );
ax = MPFR_GET_EXP (b) + MPFR_GET_EXP (c);
bq = MPFR_PREC(b);
cq = MPFR_PREC(c);
MPFR_ASSERTD(bq+cq > bq); /* PREC_MAX is /2 so no integer overflow */
bn = (bq+GMP_NUMB_BITS-1)/GMP_NUMB_BITS; /* number of limbs of b */
cn = (cq+GMP_NUMB_BITS-1)/GMP_NUMB_BITS; /* number of limbs of c */
k = bn + cn; /* effective nb of limbs used by b*c (= tn or tn+1) below */
tn = (bq + cq + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS;
/* <= k, thus no int overflow */
MPFR_ASSERTD(tn <= k);
/* Check for no size_t overflow*/
MPFR_ASSERTD((size_t) k <= ((size_t) -1) / BYTES_PER_MP_LIMB);
MPFR_TMP_MARK(marker);
tmp = (mp_limb_t *) MPFR_TMP_ALLOC((size_t) k * BYTES_PER_MP_LIMB);
/* multiplies two mantissa in temporary allocated space */
b1 = (MPFR_LIKELY(bn >= cn)) ?
mpn_mul (tmp, MPFR_MANT(b), bn, MPFR_MANT(c), cn)
: mpn_mul (tmp, MPFR_MANT(c), cn, MPFR_MANT(b), bn);
/* now tmp[0]..tmp[k-1] contains the product of both mantissa,
with tmp[k-1]>=2^(GMP_NUMB_BITS-2) */
b1 >>= GMP_NUMB_BITS - 1; /* msb from the product */
/* if the mantissas of b and c are uniformly distributed in ]1/2, 1],
then their product is in ]1/4, 1/2] with probability 2*ln(2)-1 ~ 0.386
and in [1/2, 1] with probability 2-2*ln(2) ~ 0.614 */
tmp += k - tn;
if (MPFR_UNLIKELY(b1 == 0))
mpn_lshift (tmp, tmp, tn, 1); /* tn <= k, so no stack corruption */
cc = mpfr_round_raw (MPFR_MANT (a), tmp, bq + cq,
MPFR_IS_NEG_SIGN(sign_product),
MPFR_PREC (a), rnd_mode, &inexact);
/* cc = 1 ==> result is a power of two */
if (MPFR_UNLIKELY(cc))
MPFR_MANT(a)[MPFR_LIMB_SIZE(a)-1] = MPFR_LIMB_HIGHBIT;
MPFR_TMP_FREE(marker);
{
mpfr_exp_t ax2 = ax + (mpfr_exp_t) (b1 - 1 + cc);
if (MPFR_UNLIKELY( ax2 > __gmpfr_emax))
return mpfr_overflow (a, rnd_mode, sign_product);
if (MPFR_UNLIKELY( ax2 < __gmpfr_emin))
{
/* In the rounding to the nearest mode, if the exponent of the exact
result (i.e. before rounding, i.e. without taking cc into account)
is < __gmpfr_emin - 1 or the exact result is a power of 2 (i.e. if
both arguments are powers of 2), then round to zero. */
if (rnd_mode == MPFR_RNDN &&
(ax + (mpfr_exp_t) b1 < __gmpfr_emin ||
(mpfr_powerof2_raw (b) && mpfr_powerof2_raw (c))))
rnd_mode = MPFR_RNDZ;
return mpfr_underflow (a, rnd_mode, sign_product);
}
MPFR_SET_EXP (a, ax2);
MPFR_SET_SIGN(a, sign_product);
}
MPFR_RET (inexact);
}
int
mpfr_frac (mpfr_ptr r, mpfr_srcptr u, mpfr_rnd_t rnd_mode)
{
mpfr_exp_t re, ue;
mpfr_prec_t uq;
mp_size_t un, tn, t0;
mp_limb_t *up, *tp, k;
int sh;
mpfr_t tmp;
mpfr_ptr t;
int inex;
MPFR_SAVE_EXPO_DECL (expo);
/* Special cases */
if (MPFR_UNLIKELY(MPFR_IS_NAN(u)))
{
MPFR_SET_NAN(r);
MPFR_RET_NAN;
}
else if (MPFR_UNLIKELY(MPFR_IS_INF(u) || mpfr_integer_p (u)))
{
MPFR_SET_SAME_SIGN(r, u);
MPFR_SET_ZERO(r);
MPFR_RET(0); /* zero is exact */
}
ue = MPFR_GET_EXP (u);
if (ue <= 0) /* |u| < 1 */
return mpfr_set (r, u, rnd_mode);
/* Now |u| >= 1, meaning that an overflow is not possible. */
uq = MPFR_PREC(u);
un = (uq - 1) / GMP_NUMB_BITS; /* index of most significant limb */
un -= (mp_size_t) (ue / GMP_NUMB_BITS);
/* now the index of the MSL containing bits of the fractional part */
up = MPFR_MANT(u);
sh = ue % GMP_NUMB_BITS;
k = up[un] << sh;
/* the first bit of the fractional part is the MSB of k */
if (k != 0)
{
int cnt;
count_leading_zeros(cnt, k);
/* first bit 1 of the fractional part -> MSB of the number */
re = -cnt;
sh += cnt;
MPFR_ASSERTN (sh < GMP_NUMB_BITS);
k <<= cnt;
}
else
{
re = sh - GMP_NUMB_BITS;
/* searching for the first bit 1 (exists since u isn't an integer) */
while (up[--un] == 0)
re -= GMP_NUMB_BITS;
MPFR_ASSERTN(un >= 0);
k = up[un];
count_leading_zeros(sh, k);
re -= sh;
k <<= sh;
}
/* The exponent of r will be re */
/* un: index of the limb of u that contains the first bit 1 of the FP */
t = (mp_size_t) (MPFR_PREC(r) - 1) / GMP_NUMB_BITS < un ?
(mpfr_init2 (tmp, (un + 1) * GMP_NUMB_BITS), tmp) : r;
/* t has enough precision to contain the fractional part of u */
/* If we use a temporary variable, we take the non-significant bits
of u into account, because of the mpn_lshift below. */
MPFR_SET_SAME_SIGN(t, u);
/* Put the fractional part of u into t */
tn = (MPFR_PREC(t) - 1) / GMP_NUMB_BITS;
MPFR_ASSERTN(tn >= un);
t0 = tn - un;
tp = MPFR_MANT(t);
if (sh == 0)
MPN_COPY_DECR(tp + t0, up, un + 1);
else /* warning: un may be 0 here */
tp[tn] = k | ((un) ? mpn_lshift (tp + t0, up, un, sh) : (mp_limb_t) 0);
if (t0 > 0)
MPN_ZERO(tp, t0);
MPFR_SAVE_EXPO_MARK (expo);
if (t != r)
{ /* t is tmp */
MPFR_EXP (t) = 0; /* should be re, but not necessarily in the range */
inex = mpfr_set (r, t, rnd_mode); /* no underflow */
mpfr_clear (t);
MPFR_EXP (r) += re;
}
else
{ /* There may be remaining non-significant bits in t (= r). */
int carry;
MPFR_EXP (r) = re;
carry = mpfr_round_raw (tp, tp,
(mpfr_prec_t) (tn + 1) * GMP_NUMB_BITS,
MPFR_IS_NEG (r), MPFR_PREC (r), rnd_mode,
&inex);
if (carry)
{
tp[tn] = MPFR_LIMB_HIGHBIT;
MPFR_EXP (r) ++;
}
}
MPFR_SAVE_EXPO_FREE (expo);
return mpfr_check_range (r, inex, rnd_mode);
}
int
mpfr_set_f (mpfr_ptr y, mpf_srcptr x, mpfr_rnd_t rnd_mode)
{
mp_limb_t *my, *mx, *tmp;
unsigned long cnt, sx, sy;
int inexact, carry = 0;
MPFR_TMP_DECL(marker);
sx = ABS(SIZ(x)); /* number of limbs of the mantissa of x */
if (sx == 0) /* x is zero */
{
MPFR_SET_ZERO(y);
MPFR_SET_POS(y);
return 0; /* 0 is exact */
}
if (SIZ(x) * MPFR_FROM_SIGN_TO_INT(MPFR_SIGN(y)) < 0)
MPFR_CHANGE_SIGN (y);
sy = MPFR_LIMB_SIZE (y);
my = MPFR_MANT(y);
mx = PTR(x);
count_leading_zeros(cnt, mx[sx - 1]);
if (sy <= sx) /* we may have to round even when sy = sx */
{
unsigned long xprec = sx * GMP_NUMB_BITS;
MPFR_TMP_MARK(marker);
tmp = MPFR_TMP_LIMBS_ALLOC (sx);
if (cnt)
mpn_lshift (tmp, mx, sx, cnt);
else
/* FIXME: we may avoid the copy here, and directly call mpfr_round_raw
on mx instead of tmp */
MPN_COPY (tmp, mx, sx);
carry = mpfr_round_raw (my, tmp, xprec, (SIZ(x) < 0), MPFR_PREC(y),
rnd_mode, &inexact);
if (MPFR_UNLIKELY(carry)) /* result is a power of two */
my[sy - 1] = MPFR_LIMB_HIGHBIT;
MPFR_TMP_FREE(marker);
}
else
{
if (cnt)
mpn_lshift (my + sy - sx, mx, sx, cnt);
else
MPN_COPY (my + sy - sx, mx, sx);
MPN_ZERO(my, sy - sx);
/* no rounding necessary, since y has a larger mantissa */
inexact = 0;
}
/* warning: EXP(x) * GMP_NUMB_BITS may exceed the maximal exponent */
if (EXP(x) > 1 + (__gmpfr_emax - 1) / GMP_NUMB_BITS)
{
/* EXP(x) >= 2 + floor((__gmpfr_emax-1)/GMP_NUMB_BITS)
EXP(x) >= 2 + (__gmpfr_emax - GMP_NUMB_BITS) / GMP_NUMB_BITS
>= 1 + __gmpfr_emax / GMP_NUMB_BITS
EXP(x) * GMP_NUMB_BITS >= __gmpfr_emax + GMP_NUMB_BITS
Since 0 <= cnt <= GMP_NUMB_BITS-1, and 0 <= carry <= 1,
we have then EXP(x) * GMP_NUMB_BITS - cnt + carry > __gmpfr_emax */
return mpfr_overflow (y, rnd_mode, MPFR_SIGN (y));
}
else
{
/* Do not use MPFR_SET_EXP as the exponent may be out of range. */
MPFR_EXP (y) = EXP (x) * GMP_NUMB_BITS - (mpfr_exp_t) cnt + carry;
}
return mpfr_check_range (y, inexact, rnd_mode);
}
