[Guile-commits] 08/85: Implement ceiling-remainder with new integer lib

[Andy Wingo]

wingo pushed a commit to branch main
in repository guile.

commit 55f93d7d29debb4360aa9124697560280bf8accf
Author: Andy Wingo <wingo@pobox.com>
AuthorDate: Mon Dec 13 08:57:02 2021 +0100

    Implement ceiling-remainder with new integer lib
    
    * libguile/integers.c (scm_integer_ceiling_remainder_ii)
    (scm_integer_ceiling_remainder_iz, scm_integer_ceiling_remainder_zi)
    (scm_integer_ceiling_remainder_zz): New internal functions.
    (bignum_is_positive): New helper.
    * libguile/integers.h: Declare internal functions.
    * libguile/numbers.c (scm_ceiling_remainder): Use the new functions.
---
 libguile/integers.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 libguile/integers.h |  5 +++
 libguile/numbers.c  | 92 ++++++--------------------------------------------
 3 files changed, 108 insertions(+), 85 deletions(-)

diff --git a/libguile/integers.c b/libguile/integers.c
index f27d77b54..eee09797e 100644
--- a/libguile/integers.c
+++ b/libguile/integers.c
@@ -85,6 +85,12 @@ bignum_is_negative (struct scm_bignum *z)
   return bignum_size (z) < 0;
 }
 
+static int
+bignum_is_positive (struct scm_bignum *z)
+{
+  return bignum_size (z) > 0;
+}
+
 static size_t
 bignum_limb_count (struct scm_bignum *z)
 {
@@ -382,7 +388,7 @@ scm_integer_floor_remainder_ii (scm_t_inum x, scm_t_inum y)
 SCM
 scm_integer_floor_remainder_iz (scm_t_inum x, SCM y)
 {
-  if (!bignum_is_negative (scm_bignum (y)))
+  if (bignum_is_positive (scm_bignum (y)))
     {
       if (x < 0)
         {
@@ -463,7 +469,7 @@ scm_integer_floor_divide_ii (scm_t_inum x, scm_t_inum y, 
SCM *qp, SCM *rp)
 void
 scm_integer_floor_divide_iz (scm_t_inum x, SCM y, SCM *qp, SCM *rp)
 {
-  if (!bignum_is_negative (scm_bignum (y)))
+  if (bignum_is_positive (scm_bignum (y)))
     {
       if (x < 0)
         {
@@ -555,7 +561,7 @@ scm_integer_ceiling_quotient_ii (scm_t_inum x, scm_t_inum y)
 SCM
 scm_integer_ceiling_quotient_iz (scm_t_inum x, SCM y)
 {
-  if (!bignum_is_negative (scm_bignum (y)))
+  if (bignum_is_positive (scm_bignum (y)))
     {
       if (x > 0)
         return SCM_INUM1;
@@ -610,3 +616,87 @@ scm_integer_ceiling_quotient_zz (SCM x, SCM y)
   scm_remember_upto_here_2 (x, y);
   return take_bignum_from_mpz (q);
 }
+
+SCM
+scm_integer_ceiling_remainder_ii (scm_t_inum x, scm_t_inum y)
+{
+  if (y == 0)
+    scm_num_overflow ("ceiling-remainder");
+
+  scm_t_inum r = x % y;
+  int needs_adjustment = (y > 0) ? (r > 0) : (r < 0);
+  if (needs_adjustment)
+    r -= y;
+
+  return SCM_I_MAKINUM (r);
+}
+
+SCM
+scm_integer_ceiling_remainder_iz (scm_t_inum x, SCM y)
+{
+  if (bignum_is_positive (scm_bignum (y)))
+    {
+      if (x > 0)
+        {
+          mpz_t r, zy;
+          mpz_init (r);
+          alias_bignum_to_mpz (scm_bignum (y), zy);
+          mpz_sub_ui (r, zy, x);
+          scm_remember_upto_here_1 (y);
+          mpz_neg (r, r);
+          return take_bignum_from_mpz (r);
+        }
+      else if (x == SCM_MOST_NEGATIVE_FIXNUM &&
+               bignum_cmp_long (scm_bignum (y), -SCM_MOST_NEGATIVE_FIXNUM) == 
0)
+        {
+          /* Special case: x == fixnum-min && y == abs (fixnum-min) */
+          scm_remember_upto_here_1 (y);
+          return SCM_INUM0;
+        }
+      else
+        return SCM_I_MAKINUM (x);
+    }
+  else if (x >= 0)
+    return SCM_I_MAKINUM (x);
+  else
+    {
+      mpz_t r, zy;
+      mpz_init (r);
+      alias_bignum_to_mpz (scm_bignum (y), zy);
+      mpz_add_ui (r, zy, -x);
+      scm_remember_upto_here_1 (y);
+      mpz_neg (r, r);
+      return take_bignum_from_mpz (r);
+    }
+}
+
+SCM
+scm_integer_ceiling_remainder_zi (SCM x, scm_t_inum y)
+{
+  if (y == 0)
+    scm_num_overflow ("ceiling-remainder");
+  else
+    {
+      mpz_t zx;
+      alias_bignum_to_mpz (scm_bignum (x), zx);
+      scm_t_inum r;
+      if (y > 0)
+        r = -mpz_cdiv_ui (zx, y);
+      else
+        r = mpz_fdiv_ui (zx, -y);
+      scm_remember_upto_here_1 (x);
+      return SCM_I_MAKINUM (r);
+    }
+}
+
+SCM
+scm_integer_ceiling_remainder_zz (SCM x, SCM y)
+{
+  mpz_t r, zx, zy;
+  mpz_init (r);
+  alias_bignum_to_mpz (scm_bignum (x), zx);
+  alias_bignum_to_mpz (scm_bignum (y), zy);
+  mpz_cdiv_r (r, zx, zy);
+  scm_remember_upto_here_2 (x, y);
+  return take_bignum_from_mpz (r);
+}
diff --git a/libguile/integers.h b/libguile/integers.h
index 16761bad7..acacc7ac1 100644
--- a/libguile/integers.h
+++ b/libguile/integers.h
@@ -53,6 +53,11 @@ SCM_INTERNAL SCM scm_integer_ceiling_quotient_iz (scm_t_inum 
x, SCM y);
 SCM_INTERNAL SCM scm_integer_ceiling_quotient_zi (SCM x, scm_t_inum y);
 SCM_INTERNAL SCM scm_integer_ceiling_quotient_zz (SCM x, SCM y);
 
+SCM_INTERNAL SCM scm_integer_ceiling_remainder_ii (scm_t_inum x, scm_t_inum y);
+SCM_INTERNAL SCM scm_integer_ceiling_remainder_iz (scm_t_inum x, SCM y);
+SCM_INTERNAL SCM scm_integer_ceiling_remainder_zi (SCM x, scm_t_inum y);
+SCM_INTERNAL SCM scm_integer_ceiling_remainder_zz (SCM x, SCM y);
+
 
 
 #endif  /* SCM_INTEGERS_H */
diff --git a/libguile/numbers.c b/libguile/numbers.c
index c72261081..dd532c2fc 100644
--- a/libguile/numbers.c
+++ b/libguile/numbers.c
@@ -1599,67 +1599,16 @@ SCM_PRIMITIVE_GENERIC (scm_ceiling_remainder, 
"ceiling-remainder", 2, 0, 0,
                       "@end lisp")
 #define FUNC_NAME s_scm_ceiling_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_ceiling_remainder);
-         else
-           {
-             scm_t_inum rr = xx % yy;
-             int needs_adjustment;
-
-             if (SCM_LIKELY (yy > 0))
-               needs_adjustment = (rr > 0);
-             else
-               needs_adjustment = (rr < 0);
-
-             if (needs_adjustment)
-               rr -= yy;
-             return SCM_I_MAKINUM (rr);
-           }
-       }
+      if (SCM_I_INUMP (y))
+        return scm_integer_ceiling_remainder_ii (SCM_I_INUM (x),
+                                                 SCM_I_INUM (y));
       else if (SCM_BIGP (y))
-       {
-         int sign = mpz_sgn (SCM_I_BIG_MPZ (y));
-         scm_remember_upto_here_1 (y);
-         if (SCM_LIKELY (sign > 0))
-           {
-             if (SCM_LIKELY (xx > 0))
-               {
-                 SCM r = scm_i_mkbig ();
-                 mpz_sub_ui (SCM_I_BIG_MPZ (r), SCM_I_BIG_MPZ (y), xx);
-                 scm_remember_upto_here_1 (y);
-                 mpz_neg (SCM_I_BIG_MPZ (r), SCM_I_BIG_MPZ (r));
-                 return scm_i_normbig (r);
-               }
-             else if (SCM_UNLIKELY (xx == SCM_MOST_NEGATIVE_FIXNUM)
-                      && SCM_UNLIKELY (mpz_cmp_ui (SCM_I_BIG_MPZ (y),
-                                      - SCM_MOST_NEGATIVE_FIXNUM) == 0))
-               {
-                 /* Special case: x == fixnum-min && y == abs (fixnum-min) */
-                 scm_remember_upto_here_1 (y);
-                 return SCM_INUM0;
-               }
-             else
-               return x;
-           }
-         else if (xx >= 0)
-           return x;
-         else
-           {
-             SCM r = scm_i_mkbig ();
-             mpz_add_ui (SCM_I_BIG_MPZ (r), SCM_I_BIG_MPZ (y), -xx);
-             scm_remember_upto_here_1 (y);
-             mpz_neg (SCM_I_BIG_MPZ (r), SCM_I_BIG_MPZ (r));
-             return scm_i_normbig (r);
-           }
-       }
+        return scm_integer_ceiling_remainder_iz (SCM_I_INUM (x), y);
       else if (SCM_REALP (y))
-       return scm_i_inexact_ceiling_remainder (xx, SCM_REAL_VALUE (y));
+       return scm_i_inexact_ceiling_remainder (SCM_I_INUM (x),
+                                                SCM_REAL_VALUE (y));
       else if (SCM_FRACTIONP (y))
        return scm_i_exact_rational_ceiling_remainder (x, y);
       else
@@ -1668,31 +1617,10 @@ SCM_PRIMITIVE_GENERIC (scm_ceiling_remainder, 
"ceiling-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_ceiling_remainder);
-         else
-           {
-             scm_t_inum rr;
-             if (yy > 0)
-               rr = -mpz_cdiv_ui (SCM_I_BIG_MPZ (x), yy);
-             else
-               rr = mpz_fdiv_ui (SCM_I_BIG_MPZ (x), -yy);
-             scm_remember_upto_here_1 (x);
-             return SCM_I_MAKINUM (rr);
-           }
-       }
+      if (SCM_I_INUMP (y))
+        return scm_integer_ceiling_remainder_zi (x, SCM_I_INUM (y));
       else if (SCM_BIGP (y))
-       {
-         SCM r = scm_i_mkbig ();
-         mpz_cdiv_r (SCM_I_BIG_MPZ (r),
-                     SCM_I_BIG_MPZ (x),
-                     SCM_I_BIG_MPZ (y));
-         scm_remember_upto_here_2 (x, y);
-         return scm_i_normbig (r);
-       }
+        return scm_integer_ceiling_remainder_zz (x, y);
       else if (SCM_REALP (y))
        return scm_i_inexact_ceiling_remainder
          (scm_i_big2dbl (x), SCM_REAL_VALUE (y));