Replacement of:

	* mpz/cmp_d.c, mpz/cmpabs_d.c: New files.

Don't use mpf functions from mpz.  Also take advantage of the small
value of LIMBS_PER_DOUBLE to unroll the compare loop.

1 files changed, 74 insertions, 12 deletions

diff --git a/mpz/cmpabs_d.c b/mpz/cmpabs_d.c
index 9cc45b5c3..b023ac714 100644
--- a/mpz/cmpabs_d.c
+++ b/mpz/cmpabs_d.c
@@ -23,24 +23,86 @@ MA 02111-1307, USA.
 #include "gmp.h"
 #include "gmp-impl.h"
 
+
+#define RETURN_CMP(zl, dl)              \
+  do {                                  \
+    zlimb = (zl);                       \
+    dlimb = (dl);                       \
+    if (zlimb != dlimb)                 \
+      return (zlimb >= dlimb ? 1 : -1); \
+  } while (0)
+
+#define RETURN_NONZERO(ptr, size, val)          \
+  do {                                          \
+    mp_size_t __i;                              \
+    for (__i = (size)-1; __i >= 0; __i--)       \
+      if ((ptr)[__i] != 0)                      \
+        return val;                             \
+    return 0;                                   \
+  } while (0)
+
+
 int
 mpz_cmpabs_d (mpz_srcptr z, double d)
 {
-  mp_limb_t  darray[LIMBS_PER_DOUBLE];
-  mpf_t      u, v;
-  int        zsize;
+  mp_limb_t  darray[LIMBS_PER_DOUBLE], zlimb, dlimb;
+  mp_srcptr  zp;
+  int        zsize, dexp;
 
-  zsize = ABSIZ(z);
+  /* 1. Check for either operand zero. */
+  zsize = SIZ(z);
   if (d == 0.0)
-    return zsize;
+    return (zsize != 0);
+  if (zsize == 0)
+    return (d != 0 ? -1 : 0);
+
+  /* 2. Ignore signs. */
+  zsize = ABS(zsize);
+  d = ABS(d);
+
+  /* 3. Small d, knowing abs(z) >= 1. */
+  if (d < 1.0)
+    return 1;
+
+  dexp = __gmp_extract_double (darray, d);
+  ASSERT (dexp >= 1);
+
+  /* 4. Check for different high limb positions. */
+  if (zsize != dexp)
+    return (zsize >= dexp ? 1 : -1);
+
+  /* 5. Limb data. */
+  zp = PTR(z);
+
+#if LIMBS_PER_DOUBLE == 2
+  RETURN_CMP (zp[zsize-1], darray[1]);
+  if (zsize == 1)
+    return (darray[0] != 0 ? -1 : 0);
+
+  RETURN_CMP (zp[zsize-2], darray[0]);
+  RETURN_NONZERO (zp, zsize-2, 1);
+
+#else
+#if LIMBS_PER_DOUBLE == 3
+  RETURN_CMP (zp[zsize-1], darray[2]);
+  if (zsize == 1)
+    return ((darray[0] | darray[1]) != 0 ? -1 : 0);
 
-  SIZ(u) = zsize;
-  EXP(u) = zsize;
-  PTR(u) = PTR(z);
+  RETURN_CMP (zp[zsize-2], darray[1]);
+  if (zsize == 2)
+    return (darray[0] != 0 ? -1 : 0);
 
-  PTR(v) = darray;
-  SIZ(v) = LIMBS_PER_DOUBLE;
-  EXP(v) = __gmp_extract_double (darray, ABS(d));
+  RETURN_CMP (zp[zsize-3], darray[0]);
+  RETURN_NONZERO (zp, zsize-3, 1);
 
-  return mpf_cmp (u, v);
+#else
+  for (i = 1; i <= LIMBS_PER_DOUBLE; i++)
+    {
+      RETURN_CMP (zp[zsize-i], darray[LIMBS_PER_DOUBLE-i]);
+      if (i >= zsize)
+        RETURN_NONZERO (darray, LIMBS_PER_DOUBLE-i, -1);
+    }
+  RETURN_NONZERO (zp, zsize-LIMBS_PER_DOUBLE, 1);
+#endif
+#endif
 }