[Emacs-diffs] feature/bignum 5875fba 08/24: Make arithmetic work with bignums

[Tom Tromey]

branch: feature/bignum
commit 5875fbaa2dfd919a2ba22db1d20ffa6c4c6e13bd
Author: Tom Tromey <address@hidden>
Commit: Tom Tromey <address@hidden>

    Make arithmetic work with bignums
    
    * src/data.c (free_mpz_value): New function.
    (arith_driver): Rewrite.
    (float_arith_driver): Handle bignums.
---
 src/data.c | 129 +++++++++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 95 insertions(+), 34 deletions(-)

diff --git a/src/data.c b/src/data.c
index 97554c7..b49daab 100644
--- a/src/data.c
+++ b/src/data.c
@@ -2809,16 +2809,25 @@ enum arithop
     Alogxor
   };
 
+static void
+free_mpz_value (void *value_ptr)
+{
+  mpz_clear (*(mpz_t *) value_ptr);
+}
+
 static Lisp_Object float_arith_driver (double, ptrdiff_t, enum arithop,
                                        ptrdiff_t, Lisp_Object *);
+
 static Lisp_Object
 arith_driver (enum arithop code, ptrdiff_t nargs, Lisp_Object *args)
 {
-  Lisp_Object val;
-  ptrdiff_t argnum, ok_args;
-  EMACS_INT accum = 0;
-  EMACS_INT next, ok_accum;
-  bool overflow = 0;
+  Lisp_Object val = Qnil;
+  ptrdiff_t argnum;
+  ptrdiff_t count = SPECPDL_INDEX ();
+  mpz_t accum;
+
+  mpz_init (accum);
+  record_unwind_protect_ptr (free_mpz_value, &accum);
 
   switch (code)
     {
@@ -2826,14 +2835,14 @@ arith_driver (enum arithop code, ptrdiff_t nargs, 
Lisp_Object *args)
     case Alogxor:
     case Aadd:
     case Asub:
-      accum = 0;
+      /* ACCUM is already 0.  */
       break;
     case Amult:
     case Adiv:
-      accum = 1;
+      mpz_set_si (accum, 1);
       break;
     case Alogand:
-      accum = -1;
+      mpz_set_si (accum, -1);
       break;
     default:
       break;
@@ -2841,62 +2850,112 @@ arith_driver (enum arithop code, ptrdiff_t nargs, 
Lisp_Object *args)
 
   for (argnum = 0; argnum < nargs; argnum++)
     {
-      if (! overflow)
-       {
-         ok_args = argnum;
-         ok_accum = accum;
-       }
-
-      /* Using args[argnum] as argument to CHECK_FIXNUM_... */
+      /* Using args[argnum] as argument to CHECK_NUMBER... */
       val = args[argnum];
-      CHECK_FIXNUM_OR_FLOAT_COERCE_MARKER (val);
+      CHECK_NUMBER (val);
 
       if (FLOATP (val))
-       return float_arith_driver (ok_accum, ok_args, code,
-                                  nargs, args);
-      args[argnum] = val;
-      next = XINT (args[argnum]);
+       return unbind_to (count,
+                         float_arith_driver (mpz_get_d (accum), argnum, code,
+                                             nargs, args));
       switch (code)
        {
        case Aadd:
-         overflow |= INT_ADD_WRAPV (accum, next, &accum);
+         if (BIGNUMP (val))
+           mpz_add (accum, accum, XBIGNUM (val)->value);
+         else if (XINT (val) < 0)
+           mpz_sub_ui (accum, accum, - XINT (val));
+         else
+           mpz_add_ui (accum, accum, XINT (val));
          break;
        case Asub:
          if (! argnum)
-           accum = nargs == 1 ? - next : next;
+           {
+             if (BIGNUMP (val))
+               mpz_set (accum, XBIGNUM (val)->value);
+             else
+               mpz_set_si (accum, XINT (val));
+             if (nargs == 1)
+               mpz_neg (accum, accum);
+           }
+         else if (BIGNUMP (val))
+           mpz_sub (accum, accum, XBIGNUM (val)->value);
+         else if (XINT (val) < 0)
+           mpz_add_ui (accum, accum, - XINT (val));
          else
-           overflow |= INT_SUBTRACT_WRAPV (accum, next, &accum);
+           mpz_sub_ui (accum, accum, XINT (val));
          break;
        case Amult:
-         overflow |= INT_MULTIPLY_WRAPV (accum, next, &accum);
+         if (BIGNUMP (val))
+           mpz_mul (accum, accum, XBIGNUM (val)->value);
+         else
+           mpz_mul_si (accum, accum, XINT (val));
          break;
        case Adiv:
          if (! (argnum || nargs == 1))
-           accum = next;
+           {
+             if (BIGNUMP (val))
+               mpz_set (accum, XBIGNUM (val)->value);
+             else
+               mpz_set_si (accum, XINT (val));
+           }
          else
            {
-             if (next == 0)
+             /* Note that a bignum can never be 0, so we don't need
+                to check that case.  */
+             if (FIXNUMP (val) && XINT (val) == 0)
                xsignal0 (Qarith_error);
-             if (INT_DIVIDE_OVERFLOW (accum, next))
-               overflow = true;
+             if (BIGNUMP (val))
+               mpz_tdiv_q (accum, accum, XBIGNUM (val)->value);
              else
-               accum /= next;
+               {
+                 EMACS_INT value = XINT (val);
+                 bool negate = value < 0;
+                 if (negate)
+                   value = -value;
+                 mpz_tdiv_q_ui (accum, accum, value);
+                 if (negate)
+                   mpz_neg (accum, accum);
+               }
            }
          break;
        case Alogand:
-         accum &= next;
+         if (BIGNUMP (val))
+           mpz_and (accum, accum, XBIGNUM (val)->value);
+         else
+           {
+             mpz_t tem;
+             mpz_init_set_ui (tem, XUINT (val));
+             mpz_and (accum, accum, tem);
+             mpz_clear (tem);
+           }
          break;
        case Alogior:
-         accum |= next;
+         if (BIGNUMP (val))
+           mpz_ior (accum, accum, XBIGNUM (val)->value);
+         else
+           {
+             mpz_t tem;
+             mpz_init_set_ui (tem, XUINT (val));
+             mpz_ior (accum, accum, tem);
+             mpz_clear (tem);
+           }
          break;
        case Alogxor:
-         accum ^= next;
+         if (BIGNUMP (val))
+           mpz_xor (accum, accum, XBIGNUM (val)->value);
+         else
+           {
+             mpz_t tem;
+             mpz_init_set_ui (tem, XUINT (val));
+             mpz_xor (accum, accum, tem);
+             mpz_clear (tem);
+           }
          break;
        }
     }
 
-  XSETINT (val, accum);
-  return val;
+  return unbind_to (count, make_number (accum));
 }
 
 #ifndef isnan
@@ -2919,6 +2978,8 @@ float_arith_driver (double accum, ptrdiff_t argnum, enum 
arithop code,
        {
          next = XFLOAT_DATA (val);
        }
+      else if (BIGNUMP (val))
+       next = mpz_get_d (XBIGNUM (val)->value);
       else
        {
          args[argnum] = val;    /* runs into a compiler bug. */