mirror of
https://git.savannah.gnu.org/git/guile.git
synced 2025-05-20 11:40:18 +02:00
Implement round-remainder with new integer lib
* libguile/integers.c (scm_integer_round_remainder_ii) (scm_integer_round_remainder_iz, scm_integer_round_remainder_zi) (scm_integer_round_remainder_zz): New internal functions. (integer_round_remainder_zz): New helper. (long_sign, bignum_cmp_long): New helpers. * libguile/integers.h: Declare internal functions. * libguile/numbers.c (scm_round_remainder): Use the new functions. (scm_i_bigint_round_remainder): Remove unused helper.
This commit is contained in:
Andy Wingo
parent
9a358a9632
commit
b114642640
3 changed files with 130 additions and 114 deletions
|
|
@ -1503,3 +1503,119 @@ scm_integer_round_quotient_zz (SCM x, SCM y)
|
|||
|
||||
return scm_i_normbig (q);
|
||||
}
|
||||
|
||||
static SCM
|
||||
integer_round_remainder_zz (struct scm_bignum *x, struct scm_bignum *y)
|
||||
{
|
||||
mpz_t q, r, r2, zx, zy;
|
||||
int cmp, needs_adjustment;
|
||||
|
||||
/* Note that x might be small enough to fit into a
|
||||
fixnum, so we must not let it escape into the wild */
|
||||
mpz_init (q);
|
||||
mpz_init (r);
|
||||
mpz_init (r2);
|
||||
alias_bignum_to_mpz (x, zx);
|
||||
alias_bignum_to_mpz (y, zy);
|
||||
|
||||
mpz_fdiv_qr (q, r, zx, zy);
|
||||
scm_remember_upto_here_1 (x);
|
||||
mpz_mul_2exp (r2, r, 1); /* r2 = 2*r */
|
||||
|
||||
cmp = mpz_cmpabs (r2, zy);
|
||||
if (mpz_odd_p (q))
|
||||
needs_adjustment = (cmp >= 0);
|
||||
else
|
||||
needs_adjustment = (cmp > 0);
|
||||
|
||||
if (needs_adjustment)
|
||||
mpz_sub (r, r, zy);
|
||||
|
||||
scm_remember_upto_here_1 (y);
|
||||
mpz_clear (q);
|
||||
mpz_clear (r2);
|
||||
return take_mpz (r);
|
||||
}
|
||||
|
||||
SCM
|
||||
scm_integer_round_remainder_ii (scm_t_inum x, scm_t_inum y)
|
||||
{
|
||||
if (y == 0)
|
||||
scm_num_overflow ("round-remainder");
|
||||
|
||||
scm_t_inum q = x / y;
|
||||
scm_t_inum r = x % y;
|
||||
scm_t_inum ay = y;
|
||||
scm_t_inum r2 = 2 * r;
|
||||
|
||||
if (y < 0)
|
||||
{
|
||||
ay = -ay;
|
||||
r2 = -r2;
|
||||
}
|
||||
|
||||
if (q & 1L)
|
||||
{
|
||||
if (r2 >= ay)
|
||||
r -= y;
|
||||
else if (r2 <= -ay)
|
||||
r += y;
|
||||
}
|
||||
else
|
||||
{
|
||||
if (r2 > ay)
|
||||
r -= y;
|
||||
else if (r2 < -ay)
|
||||
r += y;
|
||||
}
|
||||
|
||||
return SCM_I_MAKINUM (r);
|
||||
}
|
||||
|
||||
SCM
|
||||
scm_integer_round_remainder_iz (scm_t_inum x, SCM y)
|
||||
{
|
||||
return integer_round_remainder_zz (long_to_bignum (x), scm_bignum (y));
|
||||
}
|
||||
|
||||
SCM
|
||||
scm_integer_round_remainder_zi (SCM x, scm_t_inum y)
|
||||
{
|
||||
if (y == 0)
|
||||
scm_num_overflow ("round-remainder");
|
||||
|
||||
mpz_t q, zx;
|
||||
scm_t_inum r;
|
||||
int needs_adjustment;
|
||||
|
||||
mpz_init (q);
|
||||
alias_bignum_to_mpz (scm_bignum (x), zx);
|
||||
|
||||
if (y > 0)
|
||||
{
|
||||
r = mpz_fdiv_q_ui (q, zx, y);
|
||||
if (mpz_odd_p (q))
|
||||
needs_adjustment = (2*r >= y);
|
||||
else
|
||||
needs_adjustment = (2*r > y);
|
||||
}
|
||||
else
|
||||
{
|
||||
r = - mpz_cdiv_q_ui (q, zx, -y);
|
||||
if (mpz_odd_p (q))
|
||||
needs_adjustment = (2*r <= y);
|
||||
else
|
||||
needs_adjustment = (2*r < y);
|
||||
}
|
||||
scm_remember_upto_here_1 (x);
|
||||
mpz_clear (q);
|
||||
if (needs_adjustment)
|
||||
r -= y;
|
||||
return SCM_I_MAKINUM (r);
|
||||
}
|
||||
|
||||
SCM
|
||||
scm_integer_round_remainder_zz (SCM x, SCM y)
|
||||
{
|
||||
return integer_round_remainder_zz (scm_bignum (x), scm_bignum (y));
|
||||
}
|
||||
|
|
|
|||
|
|
@ -110,6 +110,11 @@ SCM_INTERNAL SCM scm_integer_round_quotient_iz (scm_t_inum x, SCM y);
|
|||
SCM_INTERNAL SCM scm_integer_round_quotient_zi (SCM x, scm_t_inum y);
|
||||
SCM_INTERNAL SCM scm_integer_round_quotient_zz (SCM x, SCM y);
|
||||
|
||||
SCM_INTERNAL SCM scm_integer_round_remainder_ii (scm_t_inum x, scm_t_inum y);
|
||||
SCM_INTERNAL SCM scm_integer_round_remainder_iz (scm_t_inum x, SCM y);
|
||||
SCM_INTERNAL SCM scm_integer_round_remainder_zi (SCM x, scm_t_inum y);
|
||||
SCM_INTERNAL SCM scm_integer_round_remainder_zz (SCM x, SCM y);
|
||||
|
||||
|
||||
|
||||
#endif /* SCM_INTEGERS_H */
|
||||
|
|
|
|||
|
|
@ -2533,7 +2533,6 @@ scm_i_exact_rational_round_quotient (SCM x, SCM y)
|
|||
}
|
||||
|
||||
static SCM scm_i_inexact_round_remainder (double x, double y);
|
||||
static SCM scm_i_bigint_round_remainder (SCM x, SCM y);
|
||||
static SCM scm_i_exact_rational_round_remainder (SCM x, SCM y);
|
||||
|
||||
SCM_PRIMITIVE_GENERIC (scm_round_remainder, "round-remainder", 2, 0, 0,
|
||||
|
|
@ -2556,53 +2555,15 @@ SCM_PRIMITIVE_GENERIC (scm_round_remainder, "round-remainder", 2, 0, 0,
|
|||
"@end lisp")
|
||||
#define FUNC_NAME s_scm_round_remainder
|
||||
{
|
||||
if (SCM_LIKELY (SCM_I_INUMP (x)))
|
||||
if (SCM_I_INUMP (x))
|
||||
{
|
||||
scm_t_inum xx = SCM_I_INUM (x);
|
||||
if (SCM_LIKELY (SCM_I_INUMP (y)))
|
||||
{
|
||||
scm_t_inum yy = SCM_I_INUM (y);
|
||||
if (SCM_UNLIKELY (yy == 0))
|
||||
scm_num_overflow (s_scm_round_remainder);
|
||||
else
|
||||
{
|
||||
scm_t_inum qq = xx / yy;
|
||||
scm_t_inum rr = xx % yy;
|
||||
scm_t_inum ay = yy;
|
||||
scm_t_inum r2 = 2 * rr;
|
||||
|
||||
if (SCM_LIKELY (yy < 0))
|
||||
{
|
||||
ay = -ay;
|
||||
r2 = -r2;
|
||||
}
|
||||
|
||||
if (qq & 1L)
|
||||
{
|
||||
if (r2 >= ay)
|
||||
rr -= yy;
|
||||
else if (r2 <= -ay)
|
||||
rr += yy;
|
||||
}
|
||||
else
|
||||
{
|
||||
if (r2 > ay)
|
||||
rr -= yy;
|
||||
else if (r2 < -ay)
|
||||
rr += yy;
|
||||
}
|
||||
return SCM_I_MAKINUM (rr);
|
||||
}
|
||||
}
|
||||
if (SCM_I_INUMP (y))
|
||||
return scm_integer_round_remainder_ii (SCM_I_INUM (x), SCM_I_INUM (y));
|
||||
else if (SCM_BIGP (y))
|
||||
{
|
||||
/* Pass a denormalized bignum version of x (even though it
|
||||
can fit in a fixnum) to scm_i_bigint_round_remainder */
|
||||
return scm_i_bigint_round_remainder
|
||||
(scm_i_long2big (xx), y);
|
||||
}
|
||||
return scm_integer_round_remainder_iz (SCM_I_INUM (x), y);
|
||||
else if (SCM_REALP (y))
|
||||
return scm_i_inexact_round_remainder (xx, SCM_REAL_VALUE (y));
|
||||
return scm_i_inexact_round_remainder (SCM_I_INUM (x),
|
||||
SCM_REAL_VALUE (y));
|
||||
else if (SCM_FRACTIONP (y))
|
||||
return scm_i_exact_rational_round_remainder (x, y);
|
||||
else
|
||||
|
|
@ -2611,43 +2572,10 @@ SCM_PRIMITIVE_GENERIC (scm_round_remainder, "round-remainder", 2, 0, 0,
|
|||
}
|
||||
else if (SCM_BIGP (x))
|
||||
{
|
||||
if (SCM_LIKELY (SCM_I_INUMP (y)))
|
||||
{
|
||||
scm_t_inum yy = SCM_I_INUM (y);
|
||||
if (SCM_UNLIKELY (yy == 0))
|
||||
scm_num_overflow (s_scm_round_remainder);
|
||||
else
|
||||
{
|
||||
SCM q = scm_i_mkbig ();
|
||||
scm_t_inum rr;
|
||||
int needs_adjustment;
|
||||
|
||||
if (yy > 0)
|
||||
{
|
||||
rr = mpz_fdiv_q_ui (SCM_I_BIG_MPZ (q),
|
||||
SCM_I_BIG_MPZ (x), yy);
|
||||
if (mpz_odd_p (SCM_I_BIG_MPZ (q)))
|
||||
needs_adjustment = (2*rr >= yy);
|
||||
else
|
||||
needs_adjustment = (2*rr > yy);
|
||||
}
|
||||
else
|
||||
{
|
||||
rr = - mpz_cdiv_q_ui (SCM_I_BIG_MPZ (q),
|
||||
SCM_I_BIG_MPZ (x), -yy);
|
||||
if (mpz_odd_p (SCM_I_BIG_MPZ (q)))
|
||||
needs_adjustment = (2*rr <= yy);
|
||||
else
|
||||
needs_adjustment = (2*rr < yy);
|
||||
}
|
||||
scm_remember_upto_here_2 (x, q);
|
||||
if (needs_adjustment)
|
||||
rr -= yy;
|
||||
return SCM_I_MAKINUM (rr);
|
||||
}
|
||||
}
|
||||
if (SCM_I_INUMP (y))
|
||||
return scm_integer_round_remainder_zi (x, SCM_I_INUM (y));
|
||||
else if (SCM_BIGP (y))
|
||||
return scm_i_bigint_round_remainder (x, y);
|
||||
return scm_integer_round_remainder_zz (x, y);
|
||||
else if (SCM_REALP (y))
|
||||
return scm_i_inexact_round_remainder
|
||||
(scm_i_big2dbl (x), SCM_REAL_VALUE (y));
|
||||
|
|
@ -2704,39 +2632,6 @@ scm_i_inexact_round_remainder (double x, double y)
|
|||
}
|
||||
}
|
||||
|
||||
/* Assumes that both x and y are bigints, though
|
||||
x might be able to fit into a fixnum. */
|
||||
static SCM
|
||||
scm_i_bigint_round_remainder (SCM x, SCM y)
|
||||
{
|
||||
SCM q, r, r2;
|
||||
int cmp, needs_adjustment;
|
||||
|
||||
/* Note that x might be small enough to fit into a
|
||||
fixnum, so we must not let it escape into the wild */
|
||||
q = scm_i_mkbig ();
|
||||
r = scm_i_mkbig ();
|
||||
r2 = scm_i_mkbig ();
|
||||
|
||||
mpz_fdiv_qr (SCM_I_BIG_MPZ (q), SCM_I_BIG_MPZ (r),
|
||||
SCM_I_BIG_MPZ (x), SCM_I_BIG_MPZ (y));
|
||||
scm_remember_upto_here_1 (x);
|
||||
mpz_mul_2exp (SCM_I_BIG_MPZ (r2), SCM_I_BIG_MPZ (r), 1); /* r2 = 2*r */
|
||||
|
||||
cmp = mpz_cmpabs (SCM_I_BIG_MPZ (r2), SCM_I_BIG_MPZ (y));
|
||||
if (mpz_odd_p (SCM_I_BIG_MPZ (q)))
|
||||
needs_adjustment = (cmp >= 0);
|
||||
else
|
||||
needs_adjustment = (cmp > 0);
|
||||
scm_remember_upto_here_2 (q, r2);
|
||||
|
||||
if (needs_adjustment)
|
||||
mpz_sub (SCM_I_BIG_MPZ (r), SCM_I_BIG_MPZ (r), SCM_I_BIG_MPZ (y));
|
||||
|
||||
scm_remember_upto_here_1 (y);
|
||||
return scm_i_normbig (r);
|
||||
}
|
||||
|
||||
static SCM
|
||||
scm_i_exact_rational_round_remainder (SCM x, SCM y)
|
||||
{
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue