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  1. /* Copyright (C) 2007-2015 Free Software Foundation, Inc.
  2.  
  3. This file is part of GCC.
  4.  
  5. GCC is free software; you can redistribute it and/or modify it under
  6. the terms of the GNU General Public License as published by the Free
  7. Software Foundation; either version 3, or (at your option) any later
  8. version.
  9.  
  10. GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  11. WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12. FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13. for more details.
  14.  
  15. Under Section 7 of GPL version 3, you are granted additional
  16. permissions described in the GCC Runtime Library Exception, version
  17. 3.1, as published by the Free Software Foundation.
  18.  
  19. You should have received a copy of the GNU General Public License and
  20. a copy of the GCC Runtime Library Exception along with this program;
  21. see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  22. <http://www.gnu.org/licenses/>.  */
  23.  
  24. /*****************************************************************************
  25.  *    BID128_to_string
  26.  ****************************************************************************/
  27.  
  28. #define BID_128RES
  29. #include <stdio.h>
  30. #include "bid_internal.h"
  31. #include "bid128_2_str.h"
  32. #include "bid128_2_str_macros.h"
  33.  
  34. extern int bid128_coeff_2_string (UINT64 X_hi, UINT64 X_lo,
  35.                                   char *char_ptr);
  36.  
  37. #if DECIMAL_CALL_BY_REFERENCE
  38.  
  39. void
  40. bid128_to_string (char *str,
  41.                   UINT128 *
  42.                   px _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
  43.                   _EXC_INFO_PARAM) {
  44.   UINT128 x;
  45. #else
  46.  
  47. void
  48. bid128_to_string (char *str, UINT128 x
  49.     _EXC_FLAGS_PARAM _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
  50. #endif
  51.   UINT64 x_sign;
  52.   UINT64 x_exp;
  53.   int exp;      // unbiased exponent
  54.   // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64)
  55.   int ind;
  56.   UINT128 C1;
  57.   unsigned int k = 0; // pointer in the string
  58.   unsigned int d0, d123;
  59.   UINT64 HI_18Dig, LO_18Dig, Tmp;
  60.   UINT32 MiDi[12], *ptr;
  61.   char *c_ptr_start, *c_ptr;
  62.   int midi_ind, k_lcv, len;
  63.  
  64. #if DECIMAL_CALL_BY_REFERENCE
  65.   x = *px;
  66. #endif
  67.  
  68.   BID_SWAP128(x);
  69.   // check for NaN or Infinity
  70.   if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) {
  71.     // x is special
  72.     if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN
  73.       if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN
  74.         // set invalid flag
  75.     str[0] = ((SINT64)x.w[1]<0)? '-':'+';
  76.         str[1] = 'S';
  77.         str[2] = 'N';
  78.         str[3] = 'a';
  79.         str[4] = 'N';
  80.         str[5] = '\0';
  81.       } else { // x is QNaN
  82.     str[0] = ((SINT64)x.w[1]<0)? '-':'+';
  83.         str[1] = 'Q';
  84.         str[2] = 'N';
  85.         str[3] = 'a';
  86.         str[4] = 'N';
  87.         str[5] = '\0';
  88.       }
  89.     } else { // x is not a NaN, so it must be infinity
  90.       if ((x.w[1] & MASK_SIGN) == 0x0ull) { // x is +inf
  91.         str[0] = '+';
  92.         str[1] = 'I';
  93.         str[2] = 'n';
  94.         str[3] = 'f';
  95.         str[4] = '\0';
  96.       } else { // x is -inf
  97.         str[0] = '-';
  98.         str[1] = 'I';
  99.         str[2] = 'n';
  100.         str[3] = 'f';
  101.         str[4] = '\0';
  102.       }
  103.     }
  104.     return;
  105.   } else if (((x.w[1] & MASK_COEFF) == 0x0ull) && (x.w[0] == 0x0ull)) {
  106.     // x is 0
  107.     len = 0;
  108.  
  109.     //determine if +/-
  110.     if (x.w[1] & MASK_SIGN)
  111.       str[len++] = '-';
  112.     else
  113.       str[len++] = '+';
  114.     str[len++] = '0';
  115.     str[len++] = 'E';
  116.  
  117.     // extract the exponent and print
  118.     exp = (int) (((x.w[1] & MASK_EXP) >> 49) - 6176);
  119.         if(exp > (((0x5ffe)>>1) - (6176))) {
  120.                 exp = (int) ((((x.w[1]<<2) & MASK_EXP) >> 49) - 6176);
  121.         }
  122.     if (exp >= 0) {
  123.       str[len++] = '+';
  124.       len += sprintf (str + len, "%u", exp);// should not use sprintf (should
  125.       // use sophisticated algorithm, since we know range of exp is limited)
  126.       str[len++] = '\0';
  127.     } else {
  128.       len += sprintf (str + len, "%d", exp);// should not use sprintf (should
  129.       // use sophisticated algorithm, since we know range of exp is limited)
  130.       str[len++] = '\0';
  131.     }
  132.     return;
  133.   } else { // x is not special and is not zero
  134.     // unpack x
  135.     x_sign = x.w[1] & MASK_SIGN;// 0 for positive, MASK_SIGN for negative
  136.     x_exp = x.w[1] & MASK_EXP;// biased and shifted left 49 bit positions
  137.     if ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)
  138.        x_exp = (x.w[1]<<2) & MASK_EXP;// biased and shifted left 49 bit positions
  139.     C1.w[1] = x.w[1] & MASK_COEFF;
  140.     C1.w[0] = x.w[0];
  141.     exp = (x_exp >> 49) - 6176;
  142.  
  143.     // determine sign's representation as a char
  144.     if (x_sign)
  145.       str[k++] = '-';// negative number
  146.     else
  147.       str[k++] = '+';// positive number
  148.  
  149.     // determine coefficient's representation as a decimal string
  150.  
  151.     // if zero or non-canonical, set coefficient to '0'
  152.     if ((C1.w[1] > 0x0001ed09bead87c0ull) ||
  153.         (C1.w[1] == 0x0001ed09bead87c0ull &&
  154.         (C1.w[0] > 0x378d8e63ffffffffull)) ||
  155.         ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull) ||
  156.         ((C1.w[1] == 0) && (C1.w[0] == 0))) {
  157.       str[k++] = '0';
  158.     } else {
  159.       /* ****************************************************
  160.          This takes a bid coefficient in C1.w[1],C1.w[0]
  161.          and put the converted character sequence at location
  162.          starting at &(str[k]). The function returns the number
  163.          of MiDi returned. Note that the character sequence
  164.          does not have leading zeros EXCEPT when the input is of
  165.          zero value. It will then output 1 character '0'
  166.          The algorithm essentailly tries first to get a sequence of
  167.          Millenial Digits "MiDi" and then uses table lookup to get the
  168.          character strings of these MiDis.
  169.          **************************************************** */
  170.       /* Algorithm first decompose possibly 34 digits in hi and lo
  171.          18 digits. (The high can have at most 16 digits). It then
  172.          uses macro that handle 18 digit portions.
  173.          The first step is to get hi and lo such that
  174.          2^(64) C1.w[1] + C1.w[0] = hi * 10^18  + lo,   0 <= lo < 10^18.
  175.          We use a table lookup method to obtain the hi and lo 18 digits.
  176.          [C1.w[1],C1.w[0]] = c_8 2^(107) + c_7 2^(101) + ... + c_0 2^(59) + d
  177.          where 0 <= d < 2^59 and each c_j has 6 bits. Because d fits in
  178.          18 digits,  we set hi = 0, and lo = d to begin with.
  179.          We then retrieve from a table, for j = 0, 1, ..., 8
  180.          that gives us A and B where c_j 2^(59+6j) = A * 10^18 + B.
  181.          hi += A ; lo += B; After each accumulation into lo, we normalize
  182.          immediately. So at the end, we have the decomposition as we need. */
  183.  
  184.       Tmp = C1.w[0] >> 59;
  185.       LO_18Dig = (C1.w[0] << 5) >> 5;
  186.       Tmp += (C1.w[1] << 5);
  187.       HI_18Dig = 0;
  188.       k_lcv = 0;
  189.       // Tmp = {C1.w[1]{49:0}, C1.w[0]{63:59}}
  190.       // Lo_18Dig = {C1.w[0]{58:0}}
  191.  
  192.       while (Tmp) {
  193.         midi_ind = (int) (Tmp & 0x000000000000003FLL);
  194.         midi_ind <<= 1;
  195.         Tmp >>= 6;
  196.         HI_18Dig += mod10_18_tbl[k_lcv][midi_ind++];
  197.         LO_18Dig += mod10_18_tbl[k_lcv++][midi_ind];
  198.         __L0_Normalize_10to18 (HI_18Dig, LO_18Dig);
  199.       }
  200.       ptr = MiDi;
  201.       if (HI_18Dig == 0LL) {
  202.         __L1_Split_MiDi_6_Lead (LO_18Dig, ptr);
  203.       } else {
  204.         __L1_Split_MiDi_6_Lead (HI_18Dig, ptr);
  205.         __L1_Split_MiDi_6 (LO_18Dig, ptr);
  206.       }
  207.       len = ptr - MiDi;
  208.       c_ptr_start = &(str[k]);
  209.       c_ptr = c_ptr_start;
  210.  
  211.       /* now convert the MiDi into character strings */
  212.       __L0_MiDi2Str_Lead (MiDi[0], c_ptr);
  213.       for (k_lcv = 1; k_lcv < len; k_lcv++) {
  214.         __L0_MiDi2Str (MiDi[k_lcv], c_ptr);
  215.       }
  216.       k = k + (c_ptr - c_ptr_start);
  217.     }
  218.  
  219.     // print E and sign of exponent
  220.     str[k++] = 'E';
  221.     if (exp < 0) {
  222.       exp = -exp;
  223.       str[k++] = '-';
  224.     } else {
  225.       str[k++] = '+';
  226.     }
  227.  
  228.     // determine exponent's representation as a decimal string
  229.     // d0 = exp / 1000;
  230.     // Use Property 1
  231.     d0 = (exp * 0x418a) >> 24;// 0x418a * 2^-24 = (10^(-3))RP,15
  232.     d123 = exp - 1000 * d0;
  233.  
  234.     if (d0) { // 1000 <= exp <= 6144 => 4 digits to return
  235.       str[k++] = d0 + 0x30;// ASCII for decimal digit d0
  236.       ind = 3 * d123;
  237.       str[k++] = char_table3[ind];
  238.       str[k++] = char_table3[ind + 1];
  239.       str[k++] = char_table3[ind + 2];
  240.     } else { // 0 <= exp <= 999 => d0 = 0
  241.       if (d123 < 10) { // 0 <= exp <= 9 => 1 digit to return
  242.         str[k++] = d123 + 0x30;// ASCII
  243.       } else if (d123 < 100) { // 10 <= exp <= 99 => 2 digits to return
  244.         ind = 2 * (d123 - 10);
  245.         str[k++] = char_table2[ind];
  246.         str[k++] = char_table2[ind + 1];
  247.       } else { // 100 <= exp <= 999 => 3 digits to return
  248.         ind = 3 * d123;
  249.         str[k++] = char_table3[ind];
  250.         str[k++] = char_table3[ind + 1];
  251.         str[k++] = char_table3[ind + 2];
  252.       }
  253.     }
  254.     str[k] = '\0';
  255.  
  256.   }
  257.   return;
  258.  
  259. }
  260.  
  261.  
  262. #define MAX_FORMAT_DIGITS_128   34
  263. #define MAX_STRING_DIGITS_128   100
  264. #define MAX_SEARCH              MAX_STRING_DIGITS_128-MAX_FORMAT_DIGITS_128-1
  265.  
  266.  
  267. #if DECIMAL_CALL_BY_REFERENCE
  268.  
  269. void
  270. bid128_from_string (UINT128 * pres,
  271.                     char *ps _RND_MODE_PARAM _EXC_FLAGS_PARAM
  272.                     _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
  273. #else
  274.  
  275. UINT128
  276. bid128_from_string (char *ps _RND_MODE_PARAM _EXC_FLAGS_PARAM
  277.                     _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
  278. #endif
  279.   UINT128 CX, res;
  280.   UINT64 sign_x, coeff_high, coeff_low, coeff2, coeff_l2, carry = 0x0ull,
  281.     scale_high, right_radix_leading_zeros;
  282.   int ndigits_before, ndigits_after, ndigits_total, dec_expon, sgn_exp,
  283.     i, d2, rdx_pt_enc;
  284.   char c, buffer[MAX_STRING_DIGITS_128];
  285.   int save_rnd_mode;
  286.   int save_fpsf;
  287.  
  288. #if DECIMAL_CALL_BY_REFERENCE
  289. #if !DECIMAL_GLOBAL_ROUNDING
  290.   _IDEC_round rnd_mode = *prnd_mode;
  291. #endif
  292. #endif
  293.  
  294.   save_rnd_mode = rnd_mode; // dummy
  295.   save_fpsf = *pfpsf; // dummy
  296.  
  297.   right_radix_leading_zeros = rdx_pt_enc = 0;
  298.  
  299.   // if null string, return NaN
  300.   if (!ps) {
  301.     res.w[1] = 0x7c00000000000000ull;
  302.     res.w[0] = 0;
  303.     BID_RETURN (res);
  304.   }
  305.   // eliminate leading white space
  306.   while ((*ps == ' ') || (*ps == '\t'))
  307.     ps++;
  308.  
  309.   // c gets first character
  310.   c = *ps;
  311.  
  312.  
  313.   // if c is null or not equal to a (radix point, negative sign,
  314.   // positive sign, or number) it might be SNaN, sNaN, Infinity
  315.   if (!c
  316.       || (c != '.' && c != '-' && c != '+'
  317.           && ((unsigned) (c - '0') > 9))) {
  318.     res.w[0] = 0;
  319.     // Infinity?
  320.     if ((tolower_macro (ps[0]) == 'i' && tolower_macro (ps[1]) == 'n'
  321.          && tolower_macro (ps[2]) == 'f')
  322.         && (!ps[3]
  323.             || (tolower_macro (ps[3]) == 'i'
  324.                 && tolower_macro (ps[4]) == 'n'
  325.                 && tolower_macro (ps[5]) == 'i'
  326.                 && tolower_macro (ps[6]) == 't'
  327.                 && tolower_macro (ps[7]) == 'y' && !ps[8])
  328.         )) {
  329.       res.w[1] = 0x7800000000000000ull;
  330.       BID_RETURN (res);
  331.     }
  332.     // return sNaN
  333.     if (tolower_macro (ps[0]) == 's' && tolower_macro (ps[1]) == 'n' &&
  334.         tolower_macro (ps[2]) == 'a' && tolower_macro (ps[3]) == 'n') {        
  335.         // case insensitive check for snan
  336.       res.w[1] = 0x7e00000000000000ull;
  337.       BID_RETURN (res);
  338.     } else {
  339.       // return qNaN
  340.       res.w[1] = 0x7c00000000000000ull;
  341.       BID_RETURN (res);
  342.     }
  343.   }
  344.   // if +Inf, -Inf, +Infinity, or -Infinity (case insensitive check for inf)  
  345.   if ((tolower_macro (ps[1]) == 'i' && tolower_macro (ps[2]) == 'n' &&
  346.       tolower_macro (ps[3]) == 'f') && (!ps[4] ||
  347.       (tolower_macro (ps[4]) == 'i' && tolower_macro (ps[5]) == 'n' &&
  348.       tolower_macro (ps[6]) == 'i' && tolower_macro (ps[7]) == 't' &&
  349.       tolower_macro (ps[8]) == 'y' && !ps[9]))) { // ci check for infinity
  350.     res.w[0] = 0;
  351.  
  352.     if (c == '+')
  353.       res.w[1] = 0x7800000000000000ull;
  354.     else if (c == '-')
  355.       res.w[1] = 0xf800000000000000ull;
  356.     else
  357.       res.w[1] = 0x7c00000000000000ull;
  358.  
  359.     BID_RETURN (res);
  360.   }
  361.   // if +sNaN, +SNaN, -sNaN, or -SNaN
  362.   if (tolower_macro (ps[1]) == 's' && tolower_macro (ps[2]) == 'n'
  363.       && tolower_macro (ps[3]) == 'a' && tolower_macro (ps[4]) == 'n') {
  364.     res.w[0] = 0;
  365.     if (c == '-')
  366.       res.w[1] = 0xfe00000000000000ull;
  367.     else
  368.       res.w[1] = 0x7e00000000000000ull;
  369.     BID_RETURN (res);
  370.   }
  371.   // set up sign_x to be OR'ed with the upper word later
  372.   if (c == '-')
  373.     sign_x = 0x8000000000000000ull;
  374.   else
  375.     sign_x = 0;
  376.  
  377.   // go to next character if leading sign
  378.   if (c == '-' || c == '+')
  379.     ps++;
  380.  
  381.   c = *ps;
  382.  
  383.   // if c isn't a decimal point or a decimal digit, return NaN
  384.   if (c != '.' && ((unsigned) (c - '0') > 9)) {
  385.     res.w[1] = 0x7c00000000000000ull | sign_x;
  386.     res.w[0] = 0;
  387.     BID_RETURN (res);
  388.   }
  389.   // detect zero (and eliminate/ignore leading zeros)
  390.   if (*(ps) == '0') {
  391.  
  392.     // if all numbers are zeros (with possibly 1 radix point, the number is zero
  393.     // should catch cases such as: 000.0
  394.     while (*ps == '0') {
  395.  
  396.       ps++;
  397.  
  398.       // for numbers such as 0.0000000000000000000000000000000000001001,
  399.       // we want to count the leading zeros
  400.       if (rdx_pt_enc) {
  401.         right_radix_leading_zeros++;
  402.       }
  403.       // if this character is a radix point, make sure we haven't already
  404.       // encountered one
  405.       if (*(ps) == '.') {
  406.         if (rdx_pt_enc == 0) {
  407.           rdx_pt_enc = 1;
  408.           // if this is the first radix point, and the next character is NULL,
  409.           // we have a zero
  410.           if (!*(ps + 1)) {
  411.             res.w[1] =
  412.               (0x3040000000000000ull -
  413.                (right_radix_leading_zeros << 49)) | sign_x;
  414.             res.w[0] = 0;
  415.             BID_RETURN (res);
  416.           }
  417.           ps = ps + 1;
  418.         } else {
  419.           // if 2 radix points, return NaN
  420.           res.w[1] = 0x7c00000000000000ull | sign_x;
  421.           res.w[0] = 0;
  422.           BID_RETURN (res);
  423.         }
  424.       } else if (!*(ps)) {
  425.         //res.w[1] = 0x3040000000000000ull | sign_x;
  426.         res.w[1] =
  427.           (0x3040000000000000ull -
  428.            (right_radix_leading_zeros << 49)) | sign_x;
  429.         res.w[0] = 0;
  430.         BID_RETURN (res);
  431.       }
  432.     }
  433.   }
  434.  
  435.   c = *ps;
  436.  
  437.   // initialize local variables
  438.   ndigits_before = ndigits_after = ndigits_total = 0;
  439.   sgn_exp = 0;
  440.   // pstart_coefficient = ps;
  441.  
  442.   if (!rdx_pt_enc) {
  443.     // investigate string (before radix point)
  444.     while ((unsigned) (c - '0') <= 9
  445.            && ndigits_before < MAX_STRING_DIGITS_128) {
  446.       buffer[ndigits_before] = c;
  447.       ps++;
  448.       c = *ps;
  449.       ndigits_before++;
  450.     }
  451.  
  452.     ndigits_total = ndigits_before;
  453.     if (c == '.') {
  454.       ps++;
  455.       if ((c = *ps)) {
  456.  
  457.         // investigate string (after radix point)
  458.         while ((unsigned) (c - '0') <= 9
  459.                && ndigits_total < MAX_STRING_DIGITS_128) {
  460.           buffer[ndigits_total] = c;
  461.           ps++;
  462.           c = *ps;
  463.           ndigits_total++;
  464.         }
  465.         ndigits_after = ndigits_total - ndigits_before;
  466.       }
  467.     }
  468.   } else {
  469.     // we encountered a radix point while detecting zeros
  470.     //if (c = *ps){
  471.  
  472.     c = *ps;
  473.     ndigits_total = 0;
  474.     // investigate string (after radix point)
  475.     while ((unsigned) (c - '0') <= 9
  476.            && ndigits_total < MAX_STRING_DIGITS_128) {
  477.       buffer[ndigits_total] = c;
  478.       ps++;
  479.       c = *ps;
  480.       ndigits_total++;
  481.     }
  482.     ndigits_after = ndigits_total - ndigits_before;
  483.   }
  484.  
  485.   // get exponent
  486.   dec_expon = 0;
  487.   if (ndigits_total < MAX_STRING_DIGITS_128) {
  488.     if (c) {
  489.       if (c != 'e' && c != 'E') {
  490.         // return NaN
  491.         res.w[1] = 0x7c00000000000000ull;
  492.         res.w[0] = 0;
  493.         BID_RETURN (res);
  494.       }
  495.       ps++;
  496.       c = *ps;
  497.  
  498.       if (((unsigned) (c - '0') > 9)
  499.           && ((c != '+' && c != '-') || (unsigned) (ps[1] - '0') > 9)) {
  500.         // return NaN
  501.         res.w[1] = 0x7c00000000000000ull;
  502.         res.w[0] = 0;
  503.         BID_RETURN (res);
  504.       }
  505.  
  506.       if (c == '-') {
  507.         sgn_exp = -1;
  508.         ps++;
  509.         c = *ps;
  510.       } else if (c == '+') {
  511.         ps++;
  512.         c = *ps;
  513.       }
  514.  
  515.       dec_expon = c - '0';
  516.       i = 1;
  517.       ps++;
  518.       c = *ps - '0';
  519.       while (((unsigned) c) <= 9 && i < 7) {
  520.         d2 = dec_expon + dec_expon;
  521.         dec_expon = (d2 << 2) + d2 + c;
  522.         ps++;
  523.         c = *ps - '0';
  524.         i++;
  525.       }
  526.     }
  527.  
  528.     dec_expon = (dec_expon + sgn_exp) ^ sgn_exp;
  529.   }
  530.  
  531.  
  532.   if (ndigits_total <= MAX_FORMAT_DIGITS_128) {
  533.     dec_expon +=
  534.       DECIMAL_EXPONENT_BIAS_128 - ndigits_after -
  535.       right_radix_leading_zeros;
  536.     if (dec_expon < 0) {
  537.       res.w[1] = 0 | sign_x;
  538.       res.w[0] = 0;
  539.     }
  540.     if (ndigits_total == 0) {
  541.       CX.w[0] = 0;
  542.       CX.w[1] = 0;
  543.     } else if (ndigits_total <= 19) {
  544.       coeff_high = buffer[0] - '0';
  545.       for (i = 1; i < ndigits_total; i++) {
  546.         coeff2 = coeff_high + coeff_high;
  547.         coeff_high = (coeff2 << 2) + coeff2 + buffer[i] - '0';
  548.       }
  549.       CX.w[0] = coeff_high;
  550.       CX.w[1] = 0;
  551.     } else {
  552.       coeff_high = buffer[0] - '0';
  553.       for (i = 1; i < ndigits_total - 17; i++) {
  554.         coeff2 = coeff_high + coeff_high;
  555.         coeff_high = (coeff2 << 2) + coeff2 + buffer[i] - '0';
  556.       }
  557.       coeff_low = buffer[i] - '0';
  558.       i++;
  559.       for (; i < ndigits_total; i++) {
  560.         coeff_l2 = coeff_low + coeff_low;
  561.         coeff_low = (coeff_l2 << 2) + coeff_l2 + buffer[i] - '0';
  562.       }
  563.       // now form the coefficient as coeff_high*10^19+coeff_low+carry
  564.       scale_high = 100000000000000000ull;
  565.       __mul_64x64_to_128_fast (CX, coeff_high, scale_high);
  566.  
  567.       CX.w[0] += coeff_low;
  568.       if (CX.w[0] < coeff_low)
  569.         CX.w[1]++;
  570.     }
  571.     get_BID128 (&res, sign_x, dec_expon, CX,&rnd_mode,pfpsf);
  572.     BID_RETURN (res);
  573.   } else {
  574.     // simply round using the digits that were read
  575.  
  576.     dec_expon +=
  577.       ndigits_before + DECIMAL_EXPONENT_BIAS_128 -
  578.       MAX_FORMAT_DIGITS_128 - right_radix_leading_zeros;
  579.  
  580.     if (dec_expon < 0) {
  581.       res.w[1] = 0 | sign_x;
  582.       res.w[0] = 0;
  583.     }
  584.  
  585.     coeff_high = buffer[0] - '0';
  586.     for (i = 1; i < MAX_FORMAT_DIGITS_128 - 17; i++) {
  587.       coeff2 = coeff_high + coeff_high;
  588.       coeff_high = (coeff2 << 2) + coeff2 + buffer[i] - '0';
  589.     }
  590.     coeff_low = buffer[i] - '0';
  591.     i++;
  592.     for (; i < MAX_FORMAT_DIGITS_128; i++) {
  593.       coeff_l2 = coeff_low + coeff_low;
  594.       coeff_low = (coeff_l2 << 2) + coeff_l2 + buffer[i] - '0';
  595.     }
  596.         switch(rnd_mode) {
  597.         case ROUNDING_TO_NEAREST:
  598.     carry = ((unsigned) ('4' - buffer[i])) >> 31;
  599.     if ((buffer[i] == '5' && !(coeff_low & 1)) || dec_expon < 0) {
  600.       if (dec_expon >= 0) {
  601.         carry = 0;
  602.         i++;
  603.       }
  604.       for (; i < ndigits_total; i++) {
  605.         if (buffer[i] > '0') {
  606.           carry = 1;
  607.           break;
  608.         }
  609.       }
  610.     }
  611.         break;
  612.  
  613.         case ROUNDING_DOWN:
  614.                 if(sign_x)
  615.       for (; i < ndigits_total; i++) {
  616.         if (buffer[i] > '0') {
  617.           carry = 1;
  618.           break;
  619.         }
  620.       }
  621.                 break;
  622.         case ROUNDING_UP:
  623.                 if(!sign_x)
  624.       for (; i < ndigits_total; i++) {
  625.         if (buffer[i] > '0') {
  626.           carry = 1;
  627.           break;
  628.         }
  629.       }
  630.                 break;
  631.         case ROUNDING_TO_ZERO:
  632.                 carry=0;
  633.                 break;
  634.         case ROUNDING_TIES_AWAY:
  635.     carry = ((unsigned) ('4' - buffer[i])) >> 31;
  636.     if (dec_expon < 0) {
  637.       for (; i < ndigits_total; i++) {
  638.         if (buffer[i] > '0') {
  639.           carry = 1;
  640.           break;
  641.         }
  642.       }
  643.     }
  644.                 break;
  645.  
  646.  
  647.         }
  648.     // now form the coefficient as coeff_high*10^17+coeff_low+carry
  649.     scale_high = 100000000000000000ull;
  650.     if (dec_expon < 0) {
  651.       if (dec_expon > -MAX_FORMAT_DIGITS_128) {
  652.         scale_high = 1000000000000000000ull;
  653.         coeff_low = (coeff_low << 3) + (coeff_low << 1);
  654.         dec_expon--;
  655.       }
  656.       if (dec_expon == -MAX_FORMAT_DIGITS_128
  657.           && coeff_high > 50000000000000000ull)
  658.         carry = 0;
  659.     }
  660.  
  661.     __mul_64x64_to_128_fast (CX, coeff_high, scale_high);
  662.  
  663.     coeff_low += carry;
  664.     CX.w[0] += coeff_low;
  665.     if (CX.w[0] < coeff_low)
  666.       CX.w[1]++;
  667.  
  668.  
  669.     get_BID128(&res, sign_x, dec_expon, CX, &rnd_mode, pfpsf);
  670.     BID_RETURN (res);
  671.   }
  672. }
  673.