--- cmp_ui.c.orig	Mon Aug 25 11:40:43 2003
+++ cmp_ui.c	Mon Aug 25 11:41:23 2003
@@ -85,43 +85,60 @@
 */
 
 int 
-mpfr_cmp_si_2exp (mpfr_srcptr b, long int i, int f)
+mpfr_cmp_si_2exp (mpfr_srcptr b, long int i, int f)
 {
-  int e, k, bn, si;
-  mp_limb_t c, *bp;
+  int si;
 
   MPFR_ASSERTN(!MPFR_IS_NAN(b));
 
   si = i < 0 ? -1 : 1; /* sign of i */
   if (MPFR_IS_INF(b) || (MPFR_NOTZERO(b) && MPFR_SIGN(b) != si))
     return MPFR_SIGN(b);
-  /* both signs differ */
-  else if (MPFR_IS_ZERO(b) || i == 0)
-    return i == 0 ? (MPFR_IS_ZERO(b) ? 0 : MPFR_SIGN(b)) : si;
-  else
-    { /* b and i are of same sign */
+  /* both signs differ or b = 0 */
+  else if (MPFR_IS_ZERO(b))
+    return i != 0 ? -si : 0;
+  else if (i == 0)
+    return MPFR_SIGN(b);
+  else /* b and i are of same sign si */
+    {
+      mp_exp_t e;
+      unsigned long ai;
+      int k;
+      mp_size_t bn;
+      mp_limb_t c, *bp;
+
+      ai = SAFE_ABS(long, i);
+
+      /* ai must be representable in a mp_limb_t */
+      MPFR_ASSERTN(ai == (mp_limb_t) ai);
+
       e = MPFR_EXP(b); /* 2^(e-1) <= b < 2^e */
-      if (e > f + BITS_PER_MP_LIMB)
+      if (e <= f)
+        return -si;
+      if (f < MPFR_EMAX_MAX - BITS_PER_MP_LIMB &&
+          e > f + BITS_PER_MP_LIMB)
         return si;
 
-      c = i < 0 ? - (mp_limb_t) i : (mp_limb_t) i;
+      /* now f < e <= f + BITS_PER_MP_LIMB */
+      c = (mp_limb_t) ai;
       count_leading_zeros(k, c);
-      k = f + BITS_PER_MP_LIMB - k; /* 2^(k-1) <= i*2^f < 2^k */
-      if (k != e)
-        return si * (e - k);
+      if ((int) (e - f) > BITS_PER_MP_LIMB - k)
+        return si;
+      if ((int) (e - f) < BITS_PER_MP_LIMB - k)
+        return -si;
 
-      /* now k = e */
-      c <<= f + BITS_PER_MP_LIMB - k;
+      /* now b and i*2^f have the same exponent */
+      c <<= k;
       bn = (MPFR_PREC(b) - 1) / BITS_PER_MP_LIMB;
-      bp = MPFR_MANT(b) + bn;
-      if (*bp > c)
+      bp = MPFR_MANT(b);
+      if (bp[bn] > c)
         return si;
-      if (*bp < c)
+      if (bp[bn] < c)
         return -si;
 
       /* most significant limbs agree, check remaining limbs from b */
-      while (--bn >= 0)
-        if (*--bp)
+      while (bn > 0)
+        if (bp[--bn])
           return si;
       return 0;
     }