diff --git a/libguile/integers.c b/libguile/integers.c index e9c3a067c..cfc71a8c8 100644 --- a/libguile/integers.c +++ b/libguile/integers.c @@ -1119,3 +1119,115 @@ scm_integer_centered_quotient_zz (SCM x, SCM y) { return integer_centered_quotient_zz (scm_bignum (x), scm_bignum (y)); } + +static SCM +integer_centered_remainder_zz (struct scm_bignum *x, struct scm_bignum *y) +{ + mpz_t r, min_r, zx, zy; + mpz_init (r); + mpz_init (min_r); + alias_bignum_to_mpz (x, zx); + alias_bignum_to_mpz (y, zy); + + /* Note that x might be small enough to fit into a + fixnum, so we must not let it escape into the wild */ + + /* min_r will eventually become -abs(y)/2 */ + mpz_tdiv_q_2exp (min_r, zy, 1); + + /* Arrange for r to initially be non-positive, because that simplifies + the test to see if it is within the needed bounds. */ + if (mpz_sgn (zy) > 0) + { + mpz_cdiv_r (r, zx, zy); + mpz_neg (min_r, min_r); + if (mpz_cmp (r, min_r) < 0) + mpz_add (r, r, zy); + } + else + { + mpz_fdiv_r (r, zx, zy); + if (mpz_cmp (r, min_r) < 0) + mpz_sub (r, r, zy); + } + scm_remember_upto_here_2 (x, y); + mpz_clear (min_r); + return take_mpz (r); +} + +SCM +scm_integer_centered_remainder_ii (scm_t_inum x, scm_t_inum y) +{ + if (y == 0) + scm_num_overflow ("centered-remainder"); + + scm_t_inum r = x % y; + if (x > 0) + { + if (y > 0) + { + if (r >= (y + 1) / 2) + r -= y; + } + else + { + if (r >= (1 - y) / 2) + r += y; + } + } + else + { + if (y > 0) + { + if (r < -y / 2) + r += y; + } + else + { + if (r < y / 2) + r -= y; + } + } + return SCM_I_MAKINUM (r); +} + +SCM +scm_integer_centered_remainder_iz (scm_t_inum x, SCM y) +{ + return integer_centered_remainder_zz (long_to_bignum (x), + scm_bignum (y)); +} + +SCM +scm_integer_centered_remainder_zi (SCM x, scm_t_inum y) +{ + mpz_t zx; + alias_bignum_to_mpz (scm_bignum (x), zx); + + if (y == 0) + scm_num_overflow ("centered-remainder"); + + scm_t_inum r; + /* Arrange for r to initially be non-positive, because that simplifies + the test to see if it is within the needed bounds. */ + if (y > 0) + { + r = - mpz_cdiv_ui (zx, y); + if (r < -y / 2) + r += y; + } + else + { + r = - mpz_cdiv_ui (zx, -y); + if (r < y / 2) + r -= y; + } + scm_remember_upto_here_1 (x); + return SCM_I_MAKINUM (r); +} + +SCM +scm_integer_centered_remainder_zz (SCM x, SCM y) +{ + return integer_centered_remainder_zz (scm_bignum (x), scm_bignum (y)); +} diff --git a/libguile/integers.h b/libguile/integers.h index 44dc0e376..13c69e374 100644 --- a/libguile/integers.h +++ b/libguile/integers.h @@ -91,6 +91,11 @@ SCM_INTERNAL SCM scm_integer_centered_quotient_iz (scm_t_inum x, SCM y); SCM_INTERNAL SCM scm_integer_centered_quotient_zi (SCM x, scm_t_inum y); SCM_INTERNAL SCM scm_integer_centered_quotient_zz (SCM x, SCM y); +SCM_INTERNAL SCM scm_integer_centered_remainder_ii (scm_t_inum x, scm_t_inum y); +SCM_INTERNAL SCM scm_integer_centered_remainder_iz (scm_t_inum x, SCM y); +SCM_INTERNAL SCM scm_integer_centered_remainder_zi (SCM x, scm_t_inum y); +SCM_INTERNAL SCM scm_integer_centered_remainder_zz (SCM x, SCM y); + #endif /* SCM_INTEGERS_H */ diff --git a/libguile/numbers.c b/libguile/numbers.c index fd3a8c6c7..1c915b75a 100644 --- a/libguile/numbers.c +++ b/libguile/numbers.c @@ -2208,7 +2208,6 @@ scm_i_exact_rational_centered_quotient (SCM x, SCM y) } static SCM scm_i_inexact_centered_remainder (double x, double y); -static SCM scm_i_bigint_centered_remainder (SCM x, SCM y); static SCM scm_i_exact_rational_centered_remainder (SCM x, SCM y); SCM_PRIMITIVE_GENERIC (scm_centered_remainder, "centered-remainder", 2, 0, 0, @@ -2227,54 +2226,16 @@ SCM_PRIMITIVE_GENERIC (scm_centered_remainder, "centered-remainder", 2, 0, 0, "@end lisp") #define FUNC_NAME s_scm_centered_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_centered_remainder); - else - { - scm_t_inum rr = xx % yy; - if (SCM_LIKELY (xx > 0)) - { - if (SCM_LIKELY (yy > 0)) - { - if (rr >= (yy + 1) / 2) - rr -= yy; - } - else - { - if (rr >= (1 - yy) / 2) - rr += yy; - } - } - else - { - if (SCM_LIKELY (yy > 0)) - { - if (rr < -yy / 2) - rr += yy; - } - else - { - if (rr < yy / 2) - rr -= yy; - } - } - return SCM_I_MAKINUM (rr); - } - } + if (SCM_I_INUMP (y)) + return scm_integer_centered_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_centered_remainder */ - return scm_i_bigint_centered_remainder (scm_i_long2big (xx), y); - } + return scm_integer_centered_remainder_iz (SCM_I_INUM (x), y); else if (SCM_REALP (y)) - return scm_i_inexact_centered_remainder (xx, SCM_REAL_VALUE (y)); + return scm_i_inexact_centered_remainder (SCM_I_INUM (x), + SCM_REAL_VALUE (y)); else if (SCM_FRACTIONP (y)) return scm_i_exact_rational_centered_remainder (x, y); else @@ -2283,36 +2244,10 @@ SCM_PRIMITIVE_GENERIC (scm_centered_remainder, "centered-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_centered_remainder); - else - { - scm_t_inum rr; - /* Arrange for rr to initially be non-positive, - because that simplifies the test to see - if it is within the needed bounds. */ - if (yy > 0) - { - rr = - mpz_cdiv_ui (SCM_I_BIG_MPZ (x), yy); - scm_remember_upto_here_1 (x); - if (rr < -yy / 2) - rr += yy; - } - else - { - rr = - mpz_cdiv_ui (SCM_I_BIG_MPZ (x), -yy); - scm_remember_upto_here_1 (x); - if (rr < yy / 2) - rr -= yy; - } - return SCM_I_MAKINUM (rr); - } - } + if (SCM_I_INUMP (y)) + return scm_integer_centered_remainder_zi (x, SCM_I_INUM (y)); else if (SCM_BIGP (y)) - return scm_i_bigint_centered_remainder (x, y); + return scm_integer_centered_remainder_zz (x, y); else if (SCM_REALP (y)) return scm_i_inexact_centered_remainder (scm_i_big2dbl (x), SCM_REAL_VALUE (y)); @@ -2372,48 +2307,6 @@ scm_i_inexact_centered_remainder (double x, double y) return scm_i_from_double (x - q * y); } -/* Assumes that both x and y are bigints, though - x might be able to fit into a fixnum. */ -static SCM -scm_i_bigint_centered_remainder (SCM x, SCM y) -{ - SCM r, min_r; - - /* Note that x might be small enough to fit into a - fixnum, so we must not let it escape into the wild */ - r = scm_i_mkbig (); - - /* min_r will eventually become -abs(y)/2 */ - min_r = scm_i_mkbig (); - mpz_tdiv_q_2exp (SCM_I_BIG_MPZ (min_r), - SCM_I_BIG_MPZ (y), 1); - - /* Arrange for rr to initially be non-positive, - because that simplifies the test to see - if it is within the needed bounds. */ - if (mpz_sgn (SCM_I_BIG_MPZ (y)) > 0) - { - mpz_cdiv_r (SCM_I_BIG_MPZ (r), - SCM_I_BIG_MPZ (x), SCM_I_BIG_MPZ (y)); - mpz_neg (SCM_I_BIG_MPZ (min_r), SCM_I_BIG_MPZ (min_r)); - if (mpz_cmp (SCM_I_BIG_MPZ (r), SCM_I_BIG_MPZ (min_r)) < 0) - mpz_add (SCM_I_BIG_MPZ (r), - SCM_I_BIG_MPZ (r), - SCM_I_BIG_MPZ (y)); - } - else - { - mpz_fdiv_r (SCM_I_BIG_MPZ (r), - SCM_I_BIG_MPZ (x), SCM_I_BIG_MPZ (y)); - if (mpz_cmp (SCM_I_BIG_MPZ (r), SCM_I_BIG_MPZ (min_r)) < 0) - mpz_sub (SCM_I_BIG_MPZ (r), - SCM_I_BIG_MPZ (r), - SCM_I_BIG_MPZ (y)); - } - scm_remember_upto_here_2 (x, y); - return scm_i_normbig (r); -} - static SCM scm_i_exact_rational_centered_remainder (SCM x, SCM y) {