diff --git a/libquadmath/printf/gmp-impl.h b/libquadmath/printf/gmp-impl.h
index 94d88efc57f..af0719321dc 100644
--- a/libquadmath/printf/gmp-impl.h
+++ b/libquadmath/printf/gmp-impl.h
@@ -33,15 +33,30 @@ MA 02111-1307, USA. */
 #define MAX(h,i) ((h) > (i) ? (h) : (i))
 #endif
 
-#define BITS_PER_MP_LIMB (__SIZEOF_LONG__ * __CHAR_BIT__)
-#define BYTES_PER_MP_LIMB (BITS_PER_MP_LIMB / __CHAR_BIT__)
-typedef unsigned long int	mp_limb_t;
-typedef long int		mp_limb_signed_t;
+#ifdef __MINGW32__
+  /* for MinGW targets the Microsoft ABI requires `long`
+     type will always have 32 bit, because of that we will use
+     `long` for 32-bit builds and `long long` for 64-bit builds */
+# if __x86_64__
+   typedef          long long int mp_limb_signed_t;
+   typedef unsigned long long int mp_limb_t;
+#  define BITS_PER_MP_LIMB (__SIZEOF_LONG_LONG__ * __CHAR_BIT__)
+# else // !__x86_64__
+   typedef          long int mp_limb_signed_t;
+   typedef unsigned long int mp_limb_t;
+#  define BITS_PER_MP_LIMB (__SIZEOF_LONG__ * __CHAR_BIT__)
+# endif // __x86_64__
+#else // !__MINGW32__
+  typedef          long int mp_limb_signed_t;
+  typedef unsigned long int mp_limb_t;
+# define BITS_PER_MP_LIMB (__SIZEOF_LONG__ * __CHAR_BIT__)
+#endif // __MINGW32__
 
-typedef mp_limb_t *             mp_ptr;
-typedef const mp_limb_t *	mp_srcptr;
-typedef long int                mp_size_t;
-typedef long int                mp_exp_t;
+#define BYTES_PER_MP_LIMB (BITS_PER_MP_LIMB / __CHAR_BIT__)
+typedef long int                  mp_size_t;
+typedef long int                  mp_exp_t;
+typedef mp_limb_t                *mp_ptr;
+typedef const mp_limb_t          *mp_srcptr;
 
 /* Define stuff for longlong.h.  */
 typedef unsigned int UQItype	__attribute__ ((mode (QI)));
diff --git a/libquadmath/strtod/strtod_l.c b/libquadmath/strtod/strtod_l.c
index 0b0e85a3cf7..6790124e6fc 100644
--- a/libquadmath/strtod/strtod_l.c
+++ b/libquadmath/strtod/strtod_l.c
@@ -200,7 +200,7 @@ round_and_return (mp_limb_t *retval, intmax_t exponent, int negative,
 
 	  round_limb = retval[RETURN_LIMB_SIZE - 1];
 	  round_bit = (MANT_DIG - 1) % BITS_PER_MP_LIMB;
-	  for (i = 0; i < RETURN_LIMB_SIZE; ++i)
+	  for (i = 0; i < RETURN_LIMB_SIZE - 1; ++i)
 	    more_bits |= retval[i] != 0;
 	  MPN_ZERO (retval, RETURN_LIMB_SIZE);
 	}
@@ -215,9 +215,14 @@ round_and_return (mp_limb_t *retval, intmax_t exponent, int negative,
 	  more_bits |= ((round_limb & ((((mp_limb_t) 1) << round_bit) - 1))
 			!= 0);
 
-	  (void) mpn_rshift (retval, &retval[shift / BITS_PER_MP_LIMB],
-			     RETURN_LIMB_SIZE - (shift / BITS_PER_MP_LIMB),
-			     shift % BITS_PER_MP_LIMB);
+    /* mpn_rshift requires 0 < shift < BITS_PER_MP_LIMB.  */
+    if ((shift % BITS_PER_MP_LIMB) != 0)
+      (void) mpn_rshift (retval, &retval[shift / BITS_PER_MP_LIMB],
+                          RETURN_LIMB_SIZE - (shift / BITS_PER_MP_LIMB),
+                          shift % BITS_PER_MP_LIMB);
+    else
+      for (i = 0; i < RETURN_LIMB_SIZE - (shift / BITS_PER_MP_LIMB); i++)
+        retval[i] = retval[i + (shift / BITS_PER_MP_LIMB)];
 	  MPN_ZERO (&retval[RETURN_LIMB_SIZE - (shift / BITS_PER_MP_LIMB)],
 		    shift / BITS_PER_MP_LIMB);
 	}
@@ -276,7 +281,7 @@ round_and_return (mp_limb_t *retval, intmax_t exponent, int negative,
 	}
     }
 
-  if (exponent > MAX_EXP)
+  if (exponent >= MAX_EXP)
     goto overflow;
 
 #ifdef HAVE_FENV_H
@@ -308,7 +313,7 @@ round_and_return (mp_limb_t *retval, intmax_t exponent, int negative,
     }
 #endif
 
-  if (exponent > MAX_EXP)
+  if (exponent >= MAX_EXP)
   overflow:
     return overflow_value (negative);
 
@@ -688,7 +693,7 @@ ____STRTOF_INTERNAL (nptr, endptr, group)
 	  if (endptr != NULL)
 	    *endptr = (STRING_TYPE *) cp;
 
-	  return retval;
+	  return negative ? -retval : retval;
 	}
 
       /* It is really a text we do not recognize.  */
@@ -1193,7 +1198,7 @@ ____STRTOF_INTERNAL (nptr, endptr, group)
   if (__builtin_expect (exponent > MAX_10_EXP + 1 - (intmax_t) int_no, 0))
     return overflow_value (negative);
 
-  if (__builtin_expect (exponent < MIN_10_EXP - (DIG + 1), 0))
+  if (__builtin_expect (exponent < MIN_10_EXP - (DIG + 2), 0))
     return underflow_value (negative);
 
   if (int_no > 0)
@@ -1360,7 +1365,7 @@ ____STRTOF_INTERNAL (nptr, endptr, group)
 
     assert (dig_no > int_no
 	    && exponent <= 0
-	    && exponent >= MIN_10_EXP - (DIG + 1));
+	    && exponent >= MIN_10_EXP - (DIG + 2));
 
     /* We need to compute MANT_DIG - BITS fractional bits that lie
        within the mantissa of the result, the following bit for
@@ -1651,8 +1656,8 @@ ____STRTOF_INTERNAL (nptr, endptr, group)
 	  d1 = den[densize - 2];
 
 	  /* The division does not work if the upper limb of the two-limb
-	     numerator is greater than the denominator.  */
-	  if (mpn_cmp (num, &den[densize - numsize], numsize) > 0)
+	     numerator is greater or equal to than the denominator.  */
+	  if (mpn_cmp (num, &den[densize - numsize], numsize) >= 0)
 	    num[numsize++] = 0;
 
 	  if (numsize < densize)
@@ -1761,7 +1766,7 @@ ____STRTOF_INTERNAL (nptr, endptr, group)
 	      got_limb;
 	    }
 
-	  for (i = densize; num[i] == 0 && i >= 0; --i)
+	  for (i = densize; i >= 0 && num[i] == 0; --i)
 	    ;
 	  return round_and_return (retval, exponent - 1, negative,
 				   quot, BITS_PER_MP_LIMB - 1 - used,