Extend infrastructure for double_intptr_t.

We support an unsigned version of the type, and add functions
for converting between Lisp values and both types.

* arith.c (bignum_dbl_uipt): New function, unsigned companion
to existing bignum_dbl_ipt.
(c_dbl_num, c_dbl_unum): New functions.

* arith.h (bignum_dbl_uipt, c_dbl_num, c_dbl_unum): Declared.

* configure (superulong_t, SIZEOF_DOUBLE_INTPTR,
DOUBLE_INTPTR_MAX, DOUBLE_INTPTR_MIN, DOUBLE_UINTPTR_MAX,
double_uintptr_t): New definitions going into config.h.

* lib.h (dbl_cnum, dbl_ucnum): New typedefs: double-sized
analogs of cnum and ucnum.

* mpi/mpi.c (mp_set_double_uintptr, mp_get_double_uintptr,
mp_get_double_intptr): New functions.
(s_mp_in_big_range): New static function.
(mp_in_double_intptr_range, mp_in_double_uintptr_range): New
functions.

* mpi/mpi.h (mp_set_double_uintptr,
mp_get_double_intptr, mp_get_double_uintptr,
mp_in_double_intptr_range, mp_in_double_uintptr_range):
Declared.

2 files changed, 86 insertions, 1 deletions

diff --git a/mpi/mpi.c b/mpi/mpi.c
index 2097b574..6aa905bb 100644
--- a/mpi/mpi.c
+++ b/mpi/mpi.c
@@ -471,7 +471,7 @@ mp_err mp_get_intptr(mp_int *mp, int_ptr_t *z)
 
 int mp_in_range(mp_int *mp, uint_ptr_t lim, int unsig)
 {
-  const int ptrnd = (SIZEOF_PTR + MP_DIGIT_BIT - 1) / MP_DIGIT_BIT;
+  const unsigned ptrnd = (SIZEOF_PTR + MP_DIGIT_BIT - 1) / MP_DIGIT_BIT;
   mp_size nd = USED(mp);
 
   if (unsig && ISNEG(mp))
@@ -501,6 +501,7 @@ int mp_in_uintptr_range(mp_int *mp)
 }
 
 #ifdef HAVE_DOUBLE_INTPTR_T
+
 mp_err mp_set_double_intptr(mp_int *mp, double_intptr_t z)
 {
   mp_size ix, shift;
@@ -530,6 +531,85 @@ mp_err mp_set_double_intptr(mp_int *mp, double_intptr_t z)
 
   return MP_OKAY;
 }
+
+mp_err mp_set_double_uintptr(mp_int *mp, double_uintptr_t v)
+{
+  mp_size ix, shift;
+  const mp_size nd = (sizeof v + sizeof (mp_digit) - 1) / sizeof (mp_digit);
+
+  ARGCHK(mp != NULL, MP_BADARG);
+
+  mp_zero(mp);
+
+  if (v == 0)
+    return MP_OKAY; /* shortcut for zero */
+
+  s_mp_grow(mp, nd);
+
+  USED(mp) = nd;
+
+  for (ix = 0, shift = 0; ix < nd; ix++, shift += MP_DIGIT_BIT)
+  {
+    DIGIT(mp, ix) = (v >> shift) & MP_DIGIT_MAX;
+  }
+
+  s_mp_clamp(mp);
+
+  return MP_OKAY;
+}
+
+mp_err mp_get_double_uintptr(mp_int *mp, double_uintptr_t *z)
+{
+  double_uintptr_t out = 0;
+  mp_size ix;
+  mp_size nd = USED(mp);
+  for (ix = 0; ix < nd; ix++, out <<= MP_DIGIT_BIT)
+    out |= DIGIT(mp, ix);
+
+  *z = (SIGN(mp) == MP_NEG) ? -out : out;
+  return MP_OKAY;
+}
+
+mp_err mp_get_double_intptr(mp_int *mp, double_intptr_t *z)
+{
+  double_uintptr_t tmp = 0;
+  mp_get_double_uintptr(mp, &tmp);
+  /* Reliance on bitwise unsigned to two's complement conversion */
+  *z = convert(int_ptr_t, tmp);
+  return MP_OKAY;
+}
+
+static int s_mp_in_big_range(mp_int *mp, double_uintptr_t lim, int unsig)
+{
+  const unsigned ptrnd = (SIZEOF_DOUBLE_INTPTR + MP_DIGIT_BIT - 1) / MP_DIGIT_BIT;
+  mp_size nd = USED(mp);
+
+  if (unsig && ISNEG(mp))
+    return 0;
+
+  if (nd < ptrnd)
+    return 1;
+
+  if (nd > ptrnd)
+    return 0;
+
+  {
+    mp_digit top = DIGITS(mp)[ptrnd - 1];
+    lim >>= ((ptrnd - 1) * MP_DIGIT_BIT);
+    return top <= lim;
+  }
+}
+
+int mp_in_double_intptr_range(mp_int *mp)
+{
+  return s_mp_in_big_range(mp, DOUBLE_INTPTR_MAX, 0);
+}
+
+int mp_in_double_uintptr_range(mp_int *mp)
+{
+  return s_mp_in_big_range(mp, DOUBLE_UINTPTR_MAX, 1);
+}
+
 #endif
 
 mp_err mp_set_word(mp_int *mp, mp_word w, int sign)
diff --git a/mpi/mpi.h b/mpi/mpi.h
index 71e08055..cce283b0 100644
--- a/mpi/mpi.h
+++ b/mpi/mpi.h
@@ -90,6 +90,11 @@ int mp_in_intptr_range(mp_int *mp);
 int mp_in_uintptr_range(mp_int *mp);
 #ifdef HAVE_DOUBLE_INTPTR_T
 mp_err mp_set_double_intptr(mp_int *mp, double_intptr_t z);
+mp_err mp_set_double_uintptr(mp_int *mp, double_uintptr_t z);
+mp_err mp_get_double_intptr(mp_int *mp, double_intptr_t *z);
+mp_err mp_get_double_uintptr(mp_int *mp, double_uintptr_t *z);
+int mp_in_double_intptr_range(mp_int *mp);
+int mp_in_double_uintptr_range(mp_int *mp);
 #endif
 mp_err mp_set_word(mp_int *mp, mp_word w, int sign);