Esempio n. 1
0
static void
check_random (mpfr_prec_t p)
{
  mpfr_t x,y,z,x2;
  int r;
  int i, inexact1, inexact2;

  mpfr_inits2 (p, x, y, z, x2, (mpfr_ptr) 0);

  for (i = 0 ; i < 500 ; i++)
    {
      mpfr_urandomb (y, RANDS);
      mpfr_urandomb (z, RANDS);
      if (MPFR_IS_PURE_FP(y) && MPFR_IS_PURE_FP(z))
        for(r = 0 ; r < GMP_RND_MAX ; r++)
          {
            inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
            inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
            if (mpfr_cmp(x, x2))
              STD_ERROR;
            if (inexact1 != inexact2)
              STD_ERROR2;
          }
    }

  mpfr_clears (x, y, z, x2, (mpfr_ptr) 0);
}
Esempio n. 2
0
static void
check_special (void)
{
  mpfr_t x,y,z,x2;
  int r;
  mpfr_prec_t p;
  int i = -1, inexact1, inexact2;
  mp_exp_t es;

  mpfr_inits (x, y, z, x2, (mpfr_ptr) 0);

  for (r = 0 ; r < GMP_RND_MAX ; r++)
    {
      p = 53;
      mpfr_set_prec(x, 53);
      mpfr_set_prec(x2, 53);
      mpfr_set_prec(y, 53);
      mpfr_set_prec(z, 53);

      mpfr_set_str_binary (y,
       "0.10110111101101110010010010011011000001101101011011001E31");

      mpfr_sub1sp (x, y, y, (mp_rnd_t) r);
      if (mpfr_cmp_ui(x, 0))
        {
          printf("Error for x-x with p=%lu. Expected 0. Got:", p);
          mpfr_print_binary(x);
          exit(1);
        }

      mpfr_set(z, y, (mp_rnd_t) r);
      mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp_ui(x, 0))
        {
          printf("Error for x-y with y=x and p=%lu. Expected 0. Got:", p);
          mpfr_print_binary(x);
          exit(1);
        }
      /* diff = 0 */
      mpfr_set_str_binary (y,
       "0.10110111101101110010010010011011001001101101011011001E31");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      /* Diff = 1 */
      mpfr_set_str_binary (y,
       "0.10110111101101110010010010011011000001101101011011001E30");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      /* Diff = 2 */
      mpfr_set_str_binary (y,
       "0.10110111101101110010010010011011000101101101011011001E32");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      /* Diff = 32 */
      mpfr_set_str_binary (y,
       "0.10110111101101110010010010011011000001101101011011001E63");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      /* Diff = 52 */
      mpfr_set_str_binary (y,
       "0.10110111101101110010010010011011010001101101011011001E83");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      /* Diff = 53 */
      mpfr_set_str_binary (y,
       "0.10110111101101110010010010011111000001101101011011001E31");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      /* Diff > 200 */
      mpfr_set_str_binary (y,
       "0.10110111101101110010010010011011000001101101011011001E331");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
       "0.10000000000000000000000000000000000000000000000000000E31");
      mpfr_set_str_binary (z,
       "0.11111111111111111111111111111111111111111111111111111E30");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
       "0.10000000000000000000000000000000000000000000000000000E31");
      mpfr_set_str_binary (z,
       "0.11111111111111111111111111111111111111111111111111111E29");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
       "0.10000000000000000000000000000000000000000000000000000E52");
      mpfr_set_str_binary (z,
       "0.10000000000010000000000000000000000000000000000000000E00");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
        "0.11100000000000000000000000000000000000000000000000000E53");
      mpfr_set_str_binary (z,
        "0.10000000000000000000000000000000000000000000000000000E00");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(z, y, z, (mp_rnd_t) r);
      mpfr_set(x, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
       "0.10000000000000000000000000000000000000000000000000000E53");
      mpfr_set_str_binary (z,
       "0.10100000000000000000000000000000000000000000000000000E00");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
        "0.10000000000000000000000000000000000000000000000000000E54");
      mpfr_set_str_binary (z,
        "0.10100000000000000000000000000000000000000000000000000E00");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      p = 63;
      mpfr_set_prec(x, p);
      mpfr_set_prec(x2, p);
      mpfr_set_prec(y, p);
      mpfr_set_prec(z, p);
      mpfr_set_str_binary (y,
      "0.100000000000000000000000000000000000000000000000000000000000000E62");
      mpfr_set_str_binary (z,
      "0.110000000000000000000000000000000000000000000000000000000000000E00");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      p = 64;
      mpfr_set_prec(x, 64);
      mpfr_set_prec(x2, 64);
      mpfr_set_prec(y, 64);
      mpfr_set_prec(z, 64);

      mpfr_set_str_binary (y,
      "0.1100000000000000000000000000000000000000000000000000000000000000E31");
      mpfr_set_str_binary (z,
      "0.1111111111111111111111111110000000000000000000000000011111111111E29");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
      "0.1000000000000000000000000000000000000000000000000000000000000000E63");
      mpfr_set_str_binary (z,
      "0.1011000000000000000000000000000000000000000000000000000000000000E00");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
      "0.1000000000000000000000000000000000000000000000000000000000000000E63");
      mpfr_set_str_binary (z,
      "0.1110000000000000000000000000000000000000000000000000000000000000E00");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
        "0.10000000000000000000000000000000000000000000000000000000000000E63");
      mpfr_set_str_binary (z,
        "0.10000000000000000000000000000000000000000000000000000000000000E00");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
      "0.1000000000000000000000000000000000000000000000000000000000000000E64");
      mpfr_set_str_binary (z,
      "0.1010000000000000000000000000000000000000000000000000000000000000E00");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      MPFR_SET_NAN(x);
      MPFR_SET_NAN(x2);
      mpfr_set_str_binary (y,
      "0.1000000000000000000000000000000000000000000000000000000000000000"
                          "E-1073741823");
      mpfr_set_str_binary (z,
      "0.1100000000000000000000000000000000000000000000000000000000000000"
                          "E-1073741823");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      p = 9;
      mpfr_set_prec(x, p);
      mpfr_set_prec(x2, p);
      mpfr_set_prec(y, p);
      mpfr_set_prec(z, p);

      mpfr_set_str_binary (y, "0.100000000E1");
      mpfr_set_str_binary (z, "0.100000000E-8");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      p = 34;
      mpfr_set_prec(x, p);
      mpfr_set_prec(x2, p);
      mpfr_set_prec(y, p);
      mpfr_set_prec(z, p);

      mpfr_set_str_binary (y, "-0.1011110000111100010111011100110100E-18");
      mpfr_set_str_binary (z, "0.1000101010110011010101011110000000E-14");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      p = 124;
      mpfr_set_prec(x, p);
      mpfr_set_prec(x2, p);
      mpfr_set_prec(y, p);
      mpfr_set_prec(z, p);

      mpfr_set_str_binary (y,
"0.1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000E1");
      mpfr_set_str_binary (z,
"0.1011111000100111000011001000011101010101101100101010101001000001110100001101110110001110111010000011101001100010111110001100E-31");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      p = 288;
      mpfr_set_prec(x, p);
      mpfr_set_prec(x2, p);
      mpfr_set_prec(y, p);
      mpfr_set_prec(z, p);

      mpfr_set_str_binary (y,
     "0.111000110011000001000111101010111011110011101001101111111110000011100101000001001010110010101010011001010100000001110011110001010101101010001011101110100100001011110100110000101101100011010001001011011010101010000010001101001000110010010111111011110001111101001000101101001100101100101000E80");
      mpfr_set_str_binary (z,
     "-0.100001111111101001011010001100110010100111001110000110011101001011010100001000000100111011010110110010000000000010101101011000010000110001110010100001100101011100100100001011000100011110000001010101000100011101001000010111100000111000111011001000100100011000100000010010111000000100100111E-258");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      p = 85;
      mpfr_set_prec(x, p);
      mpfr_set_prec(x2, p);
      mpfr_set_prec(y, p);
      mpfr_set_prec(z, p);

      mpfr_set_str_binary (y,
"0.1111101110100110110110100010101011101001100010100011110110110010010011101100101111100E-4");
      mpfr_set_str_binary (z,
"0.1111101110100110110110100010101001001000011000111000011101100101110100001110101010110E-4");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      p = 64;
      mpfr_set_prec(x, p); mpfr_set_prec(x2, p);
      mpfr_set_prec(y, p); mpfr_set_prec(z, p);

      mpfr_set_str_binary (y,
                          "0.11000000000000000000000000000000"
                          "00000000000000000000000000000000E1");
      mpfr_set_str_binary (z,
                          "0.10000000000000000000000000000000"
                          "00000000000000000000000000000001E0");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
                          "0.11000000000000000000000000000000"
                          "000000000000000000000000000001E1");
      mpfr_set_str_binary (z,
                          "0.10000000000000000000000000000000"
                          "00000000000000000000000000000001E0");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      es = mpfr_get_emin ();
      set_emin (-1024);

      mpfr_set_str_binary (y,
                          "0.10000000000000000000000000000000"
                          "000000000000000000000000000000E-1023");
      mpfr_set_str_binary (z,
                          "0.10000000000000000000000000000000"
                          "00000000000000000000000000000001E-1023");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      mpfr_set_str_binary (y,
                           "0.10000000000000000000000000000000"
                           "000000000000000000000000000000E-1023");
      mpfr_set_str_binary (z,
                           "0.1000000000000000000000000000000"
                           "000000000000000000000000000000E-1023");
      inexact1 = mpfr_sub1(x2, y, z, (mp_rnd_t) r);
      inexact2 = mpfr_sub1sp(x, y, z, (mp_rnd_t) r);
      if (mpfr_cmp(x, x2))
        STD_ERROR;
      if (inexact1 != inexact2)
        STD_ERROR2;

      set_emin (es);
    }

  mpfr_clears (x, y, z, x2, (mpfr_ptr) 0);
}
Esempio n. 3
0
int
mpfr_sub (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t rnd_mode)
{
  MPFR_LOG_FUNC (("b[%#R]=%R c[%#R]=%R rnd=%d", b, b, c, c, rnd_mode),
                 ("a[%#R]=%R", a, a));

  if (MPFR_ARE_SINGULAR (b,c))
    {
      if (MPFR_IS_NAN (b) || MPFR_IS_NAN (c))
        {
          MPFR_SET_NAN (a);
          MPFR_RET_NAN;
        }
      else if (MPFR_IS_INF (b))
        {
          if (!MPFR_IS_INF (c) || MPFR_SIGN (b) != MPFR_SIGN(c))
            {
              MPFR_SET_INF (a);
              MPFR_SET_SAME_SIGN (a, b);
              MPFR_RET (0); /* exact */
            }
          else
            {
              MPFR_SET_NAN (a); /* Inf - Inf */
              MPFR_RET_NAN;
            }
        }
      else if (MPFR_IS_INF (c))
        {
          MPFR_SET_INF (a);
          MPFR_SET_OPPOSITE_SIGN (a, c);
          MPFR_RET (0); /* exact */
        }
      else if (MPFR_IS_ZERO (b))
        {
          if (MPFR_IS_ZERO (c))
            {
              int sign = rnd_mode != MPFR_RNDD
                ? ((MPFR_IS_NEG(b) && MPFR_IS_POS(c)) ? -1 : 1)
                : ((MPFR_IS_POS(b) && MPFR_IS_NEG(c)) ? 1 : -1);
              MPFR_SET_SIGN (a, sign);
              MPFR_SET_ZERO (a);
              MPFR_RET(0); /* 0 - 0 is exact */
            }
          else
            return mpfr_neg (a, c, rnd_mode);
        }
      else
        {
          MPFR_ASSERTD (MPFR_IS_ZERO (c));
          return mpfr_set (a, b, rnd_mode);
        }
    }
  MPFR_ASSERTD (MPFR_IS_PURE_FP (b) && MPFR_IS_PURE_FP (c));

  if (MPFR_LIKELY (MPFR_SIGN (b) == MPFR_SIGN (c)))
    { /* signs are equal, it's a real subtraction */
      if (MPFR_LIKELY (MPFR_PREC (a) == MPFR_PREC (b)
                       && MPFR_PREC (b) == MPFR_PREC (c)))
        return mpfr_sub1sp (a, b, c, rnd_mode);
      else
        return mpfr_sub1 (a, b, c, rnd_mode);
    }
  else
    { /* signs differ, it's an addition */
      if (MPFR_GET_EXP (b) < MPFR_GET_EXP (c))
         { /* exchange rounding modes toward +/- infinity */
          int inexact;
          rnd_mode = MPFR_INVERT_RND (rnd_mode);
          if (MPFR_LIKELY (MPFR_PREC (a) == MPFR_PREC (b)
                           && MPFR_PREC (b) == MPFR_PREC (c)))
            inexact = mpfr_add1sp (a, c, b, rnd_mode);
          else
            inexact = mpfr_add1 (a, c, b, rnd_mode);
          MPFR_CHANGE_SIGN (a);
          return -inexact;
        }
      else
        {
          if (MPFR_LIKELY (MPFR_PREC (a) == MPFR_PREC (b)
                           && MPFR_PREC (b) == MPFR_PREC (c)))
            return mpfr_add1sp (a, b, c, rnd_mode);
          else
            return mpfr_add1 (a, b, c, rnd_mode);
        }
    }
}
int
mpfr_add (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t rnd_mode)
{
  MPFR_LOG_FUNC (("b[%#R]=%R c[%#R]=%R rnd=%d", b, b, c, c, rnd_mode),
                 ("a[%#R]=%R", a, a));

  if (MPFR_ARE_SINGULAR(b,c))
    {
      if (MPFR_IS_NAN(b) || MPFR_IS_NAN(c))
        {
          MPFR_SET_NAN(a);
          MPFR_RET_NAN;
        }
      /* neither b nor c is NaN here */
      else if (MPFR_IS_INF(b))
        {
          if (!MPFR_IS_INF(c) || MPFR_SIGN(b) == MPFR_SIGN(c))
            {
              MPFR_SET_INF(a);
              MPFR_SET_SAME_SIGN(a, b);
              MPFR_RET(0); /* exact */
            }
          else
            {
              MPFR_SET_NAN(a);
              MPFR_RET_NAN;
            }
        }
      else if (MPFR_IS_INF(c))
          {
            MPFR_SET_INF(a);
            MPFR_SET_SAME_SIGN(a, c);
            MPFR_RET(0); /* exact */
          }
      /* now either b or c is zero */
      else if (MPFR_IS_ZERO(b))
        {
          if (MPFR_IS_ZERO(c))
            {
              /* for round away, we take the same convention for 0 + 0
                 as for round to zero or to nearest: it always gives +0,
                 except (-0) + (-0) = -0. */
              MPFR_SET_SIGN(a,
                            (rnd_mode != MPFR_RNDD ?
                             ((MPFR_IS_NEG(b) && MPFR_IS_NEG(c)) ? -1 : 1) :
                             ((MPFR_IS_POS(b) && MPFR_IS_POS(c)) ? 1 : -1)));
              MPFR_SET_ZERO(a);
              MPFR_RET(0); /* 0 + 0 is exact */
            }
          return mpfr_set (a, c, rnd_mode);
        }
      else
        {
          MPFR_ASSERTD(MPFR_IS_ZERO(c));
          return mpfr_set (a, b, rnd_mode);
        }
    }

  MPFR_ASSERTD(MPFR_IS_PURE_FP(b) && MPFR_IS_PURE_FP(c));

  if (MPFR_UNLIKELY(MPFR_SIGN(b) != MPFR_SIGN(c)))
    { /* signs differ, it's a subtraction */
      if (MPFR_LIKELY(MPFR_PREC(a) == MPFR_PREC(b)
                      && MPFR_PREC(b) == MPFR_PREC(c)))
        return mpfr_sub1sp(a,b,c,rnd_mode);
      else
        return mpfr_sub1(a, b, c, rnd_mode);
    }
  else
    { /* signs are equal, it's an addition */
      if (MPFR_LIKELY(MPFR_PREC(a) == MPFR_PREC(b)
                      && MPFR_PREC(b) == MPFR_PREC(c)))
        if (MPFR_GET_EXP(b) < MPFR_GET_EXP(c))
          return mpfr_add1sp(a, c, b, rnd_mode);
        else
          return mpfr_add1sp(a, b, c, rnd_mode);
      else
        if (MPFR_GET_EXP(b) < MPFR_GET_EXP(c))
          return mpfr_add1(a, c, b, rnd_mode);
        else
          return mpfr_add1(a, b, c, rnd_mode);
    }
}