1 files changed, 127 insertions, 0 deletions
diff --git a/src/bignum.h b/src/bignum.h
new file mode 100644
index 00000000000..de9ee17c027
--- /dev/null
+++ b/src/bignum.h
@@ -0,0 +1,127 @@
+/* Big numbers for Emacs.
+
+Copyright 2018-2022 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Include this header only if access to bignum internals is needed.  */
+
+#ifndef BIGNUM_H
+#define BIGNUM_H
+
+#include <gmp.h>
+#include "lisp.h"
+
+/* Number of data bits in a limb.  */
+#ifndef GMP_NUMB_BITS
+enum { GMP_NUMB_BITS = TYPE_WIDTH (mp_limb_t) };
+#endif
+
+struct Lisp_Bignum
+{
+  union vectorlike_header header;
+  mpz_t value;
+} GCALIGNED_STRUCT;
+
+extern mpz_t mpz[5];
+
+extern void init_bignum (void);
+extern Lisp_Object make_integer_mpz (void);
+extern bool mpz_to_intmax (mpz_t const, intmax_t *) ARG_NONNULL ((1, 2));
+extern bool mpz_to_uintmax (mpz_t const, uintmax_t *) ARG_NONNULL ((1, 2));
+extern void mpz_set_intmax_slow (mpz_t, intmax_t) ARG_NONNULL ((1));
+extern void mpz_set_uintmax_slow (mpz_t, uintmax_t) ARG_NONNULL ((1));
+extern void emacs_mpz_mul (mpz_t, mpz_t const, mpz_t const)
+  ARG_NONNULL ((1, 2, 3));
+extern void emacs_mpz_mul_2exp (mpz_t, mpz_t const, EMACS_INT)
+  ARG_NONNULL ((1, 2));
+extern void emacs_mpz_pow_ui (mpz_t, mpz_t const, unsigned long)
+  ARG_NONNULL ((1, 2));
+extern double mpz_get_d_rounded (mpz_t const) ATTRIBUTE_CONST;
+extern Lisp_Object get_random_bignum (struct Lisp_Bignum const *);
+
+INLINE_HEADER_BEGIN
+
+INLINE struct Lisp_Bignum *
+XBIGNUM (Lisp_Object a)
+{
+  eassert (BIGNUMP (a));
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Bignum);
+}
+
+INLINE void ARG_NONNULL ((1))
+mpz_set_intmax (mpz_t result, intmax_t v)
+{
+  /* mpz_set_si works in terms of long, but Emacs may use a wider
+     integer type, and so sometimes will have to construct the mpz_t
+     by hand.  */
+  if (LONG_MIN <= v && v <= LONG_MAX)
+    mpz_set_si (result, v);
+  else
+    mpz_set_intmax_slow (result, v);
+}
+INLINE void ARG_NONNULL ((1))
+mpz_set_uintmax (mpz_t result, uintmax_t v)
+{
+  if (v <= ULONG_MAX)
+    mpz_set_ui (result, v);
+  else
+    mpz_set_uintmax_slow (result, v);
+}
+
+/* Return a pointer to the mpz_t value represented by the bignum I.
+   It is const because the value should not change.  */
+INLINE mpz_t const *
+bignum_val (struct Lisp_Bignum const *i)
+{
+  return &i->value;
+}
+INLINE mpz_t const *
+xbignum_val (Lisp_Object i)
+{
+  return bignum_val (XBIGNUM (i));
+}
+
+/* Return a pointer to an mpz_t that is equal to the Lisp integer I.
+   If I is a bignum this returns a pointer to I's representation;
+   otherwise this sets *TMP to I's value and returns TMP.  */
+INLINE mpz_t const *
+bignum_integer (mpz_t *tmp, Lisp_Object i)
+{
+  if (FIXNUMP (i))
+    {
+      mpz_set_intmax (*tmp, XFIXNUM (i));
+      /* The unnecessary cast pacifies a buggy GCC 4.8.5.  */
+      return (mpz_t const *) tmp;
+    }
+  return xbignum_val (i);
+}
+
+/* Set RESULT to the value stored in the Lisp integer I.  If I is a
+   big integer, copy it to RESULT.  RESULT must already be
+   initialized.  */
+INLINE void
+mpz_set_integer (mpz_t result, Lisp_Object i)
+{
+  if (FIXNUMP (i))
+    mpz_set_intmax (result, XFIXNUM (i));
+  else
+    mpz_set (result, *xbignum_val (i));
+}
+
+INLINE_HEADER_END
+
+#endif /* BIGNUM_H */