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#include "bid_trans.h"

static BID_UINT128 BID128_1 =
  {BID128_LH_INIT( 0x0000000000000001ull, 0x3040000000000000ull )};
static BID_UINT128 BID128_10POW4464 =
  {BID128_LH_INIT( 0x0000000000000001ull, 0x5320000000000000ull )};
static BID_UINT128 BID128_10POWN4464 =
  {BID128_LH_INIT( 0x0000000000000001ull, 0x0d60000000000000ull )};

BID_F128_CONST_DEF(c_inv_log10, 3ffdbcb7b1526e50, e32a6ab7555f5a68); // 1/log10
BID_F128_CONST_DEF(c_4464,  400b170000000000, 0000000000000000); // 4464
BID_F128_CONST_DEF(c_one,   3fff000000000000, 0000000000000000); // 1.0
BID_F128_CONST_DEF(c_half,  3ffe000000000000, 0000000000000000); // 1.0

BID128_FUNCTION_ARG1 (bid128_log10, x)

  BID_F128_TYPE xq, rq;
  BID_UINT128 res;
  int z, cmp_res;

// Check for NaN and just return the same NaN, quieted and canonized

  if ((x.w[BID_HIGH_128W] & NAN_MASK64) == NAN_MASK64)
   {
     #ifdef BID_SET_STATUS_FLAGS
     if (((x.w[BID_HIGH_128W] & SNAN_MASK64) == SNAN_MASK64))
        __set_status_flags (pfpsf, BID_INVALID_EXCEPTION);
     #endif
     res.w[BID_HIGH_128W] = x.w[BID_HIGH_128W] & 0xfc003fffffffffffull;
     res.w[BID_LOW_128W] = x.w[BID_LOW_128W];
     if (((res.w[BID_HIGH_128W] & 0x00003fffffffffffull) >
          0x0000314dc6448d93ull) ||
         (((res.w[BID_HIGH_128W] & 0x00003fffffffffffull) ==
            0x0000314dc6448d93ull) &&
          res.w[BID_LOW_128W] >= 0x38c15b0a00000000ull))
      { res.w[BID_HIGH_128W] &= ~0x00003fffffffffffull;
        res.w[BID_LOW_128W] = 0ull;
      }
     BID_RETURN(res);
   }

  BIDECIMAL_CALL1_NORND_NOSTAT (bid128_isZero, z, x);
  if (z)
   { // -Infinite and Divide by Zero according C99
     res.w[BID_HIGH_128W] = 0xf800000000000000ull;
     res.w[BID_LOW_128W] = 0ull;
     #ifdef BID_SET_STATUS_FLAGS
     __set_status_flags (pfpsf, BID_ZERO_DIVIDE_EXCEPTION);
     #endif
     BID_RETURN(res);
   }

  if (x.w[BID_HIGH_128W] & MASK_SIGN)
   { // QNaN Indefinite
     res.w[BID_HIGH_128W] = 0x7c00000000000000ull;
     res.w[BID_LOW_128W] = 0ull;
     #ifdef BID_SET_STATUS_FLAGS
     __set_status_flags (pfpsf, BID_INVALID_EXCEPTION);
     #endif
     BID_RETURN (res);
   }

// Inputs too large to fit in quad.

  BIDECIMAL_CALL2_NORND(bid128_quiet_greater,cmp_res, x, BID128_10POW4464);
  if (cmp_res)
   { BID_UINT128 x_mod;
     BIDECIMAL_CALL2 (bid128_mul, x_mod, x, BID128_10POWN4464);
     BIDECIMAL_CALL1 (bid128_to_binary128, xq, x_mod);
     __bid_f128_log(rq, xq);
     __bid_f128_mul(rq, rq, c_inv_log10.v);
     __bid_f128_add(rq, rq, c_4464.v);
     BIDECIMAL_CALL1 (binary128_to_bid128, res, rq);
     BID_RETURN (res);
   }

// Inputs so small they underflow to zero in quad.

  BIDECIMAL_CALL2_NORND(bid128_quiet_less,cmp_res,x,BID128_10POWN4464);
  if (cmp_res)
   { BID_UINT128 x_mod;
     BIDECIMAL_CALL2(bid128_mul, x_mod, x, BID128_10POW4464);
     BIDECIMAL_CALL1(bid128_to_binary128, xq, x_mod);
     __bid_f128_log(rq, xq);
     __bid_f128_mul(rq, rq, c_inv_log10.v);
     __bid_f128_sub(rq, rq, c_4464.v); 
     BIDECIMAL_CALL1 (binary128_to_bid128, res, rq);
     BID_RETURN (res);
   }

// Ordinary inputs

  else
   { BID_F128_TYPE e_bin, e_bin_a;
     BIDECIMAL_CALL1 (bid128_to_binary128, xq, x);
     __bid_f128_log(rq, xq);
     __bid_f128_sub(e_bin, xq, c_one.v);
	 __bid_f128_fabs(e_bin_a, e_bin);
     if (__bid_f128_lt(e_bin_a, c_half.v))
      { BID_F128_TYPE tmp_e_bin, rt;
        BID_UINT128 e;
        BIDECIMAL_CALL2 (bid128_sub, e, x, BID128_1);
        BIDECIMAL_CALL1 (bid128_to_binary128, tmp_e_bin, e);
        __bid_f128_sub(rt, e_bin, tmp_e_bin);
	__bid_f128_div(rt, rt, xq);
	__bid_f128_sub(rq, rq, rt);
      }
     __bid_f128_mul(rq, rq, c_inv_log10.v);
     BIDECIMAL_CALL1 (binary128_to_bid128, res, rq);
     BID_RETURN (res);
   }
}
