diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/mpn2ldbl.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-128ibm/mpn2ldbl.c | 44 |
1 files changed, 21 insertions, 23 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/mpn2ldbl.c b/sysdeps/ieee754/ldbl-128ibm/mpn2ldbl.c index c3e42f2284..c96852dfd9 100644 --- a/sysdeps/ieee754/ldbl-128ibm/mpn2ldbl.c +++ b/sysdeps/ieee754/ldbl-128ibm/mpn2ldbl.c @@ -69,9 +69,9 @@ __mpn_construct_long_double (mp_srcptr frac_ptr, int expt, int sign) else lzcount = __builtin_clzl ((long) val) + 32; if (hi) - lzcount = lzcount - 11; + lzcount = lzcount - (64 - 53); else - lzcount = lzcount + 42; + lzcount = lzcount + 53 - (64 - 53); if (lzcount > u.d[0].ieee.exponent) { @@ -97,29 +97,27 @@ __mpn_construct_long_double (mp_srcptr frac_ptr, int expt, int sign) } } - if (lo != 0L) + if (lo != 0) { - /* hidden2 bit of low double controls rounding of the high double. - If hidden2 is '1' and either the explicit mantissa is non-zero + /* hidden bit of low double controls rounding of the high double. + If hidden is '1' and either the explicit mantissa is non-zero or hi is odd, then round up hi and adjust lo (2nd mantissa) plus change the sign of the low double to compensate. */ if ((lo & (1LL << 52)) != 0 - && ((hi & 1) != 0 || (lo & ((1LL << 52) - 1)))) + && ((hi & 1) != 0 || (lo & ((1LL << 52) - 1)) != 0)) { hi++; - if ((hi & ((1LL << 52) - 1)) == 0) + if ((hi & (1LL << 53)) != 0) { - if ((hi & (1LL << 53)) != 0) - hi -= 1LL << 52; + hi >>= 1; u.d[0].ieee.exponent++; } u.d[1].ieee.negative = !sign; lo = (1LL << 53) - lo; } - /* The hidden bit of the lo mantissa is zero so we need to normalize - it for the low double. Shift it left until the hidden bit is '1' - then adjust the 2nd exponent accordingly. */ + /* Normalize the low double. Shift the mantissa left until + the hidden bit is '1' and adjust the exponent accordingly. */ if (sizeof (lo) == sizeof (long)) lzcount = __builtin_clzl (lo); @@ -127,24 +125,24 @@ __mpn_construct_long_double (mp_srcptr frac_ptr, int expt, int sign) lzcount = __builtin_clzl ((long) (lo >> 32)); else lzcount = __builtin_clzl ((long) lo) + 32; - lzcount = lzcount - 11; - if (lzcount > 0) - { - lo = lo << lzcount; - exponent2 = exponent2 - lzcount; - } + lzcount = lzcount - (64 - 53); + lo <<= lzcount; + exponent2 -= lzcount; + if (exponent2 > 0) u.d[1].ieee.exponent = exponent2; - else + else if (exponent2 > -53) lo >>= 1 - exponent2; + else + lo = 0; } else u.d[1].ieee.negative = 0; - u.d[1].ieee.mantissa1 = lo & 0xffffffffLL; - u.d[1].ieee.mantissa0 = (lo >> 32) & 0xfffff; - u.d[0].ieee.mantissa1 = hi & 0xffffffffLL; - u.d[0].ieee.mantissa0 = (hi >> 32) & ((1LL << (LDBL_MANT_DIG - 86)) - 1); + u.d[1].ieee.mantissa1 = lo; + u.d[1].ieee.mantissa0 = lo >> 32; + u.d[0].ieee.mantissa1 = hi; + u.d[0].ieee.mantissa0 = hi >> 32; return u.ld; } |