diff options
Diffstat (limited to 'gcc/dfp.cc')
| -rw-r--r-- | gcc/dfp.cc | 79 |
1 files changed, 78 insertions, 1 deletions
@@ -619,11 +619,21 @@ decimal_real_to_integer (const REAL_VALUE_TYPE *r, bool *fail, int precision) decNumber dn, dn2, dn3; REAL_VALUE_TYPE to; char string[256]; + int scale = 0; decContextDefault (&set, DEC_INIT_DECIMAL128); set.traps = 0; set.round = DEC_ROUND_DOWN; decimal128ToNumber ((const decimal128 *) r->sig, &dn); + if (precision > 64 && decNumberIsFinite (&dn) && dn.exponent > 0) + { + /* libdecNumber doesn't really handle too large integers. + So when precision is large and exponent as well, trim the + exponent and adjust the resulting wide_int by multiplying + it multiple times with powers of ten. */ + scale = dn.exponent; + dn.exponent = 0; + } decNumberToIntegralValue (&dn2, &dn, &set); decNumberZero (&dn3); @@ -633,7 +643,74 @@ decimal_real_to_integer (const REAL_VALUE_TYPE *r, bool *fail, int precision) function. */ decNumberToString (&dn, string); real_from_string (&to, string); - return real_to_integer (&to, fail, precision); + bool failp = false; + wide_int w = real_to_integer (&to, &failp, precision); + if (failp) + *fail = true; + if (scale && !failp) + { + bool isneg = wi::neg_p (w); + if (isneg) + w = -w; + enum wi::overflow_type ovf = wi::OVF_NONE; + unsigned HOST_WIDE_INT pow10s[] = { + HOST_WIDE_INT_UC (10), + HOST_WIDE_INT_UC (100), + HOST_WIDE_INT_UC (1000), + HOST_WIDE_INT_UC (10000), + HOST_WIDE_INT_UC (100000), + HOST_WIDE_INT_UC (1000000), + HOST_WIDE_INT_UC (10000000), + HOST_WIDE_INT_UC (100000000), + HOST_WIDE_INT_UC (1000000000), + HOST_WIDE_INT_UC (10000000000), + HOST_WIDE_INT_UC (100000000000), + HOST_WIDE_INT_UC (1000000000000), + HOST_WIDE_INT_UC (10000000000000), + HOST_WIDE_INT_UC (100000000000000), + HOST_WIDE_INT_UC (1000000000000000), + HOST_WIDE_INT_UC (10000000000000000), + HOST_WIDE_INT_UC (100000000000000000), + HOST_WIDE_INT_UC (1000000000000000000), + HOST_WIDE_INT_UC (10000000000000000000), + }; + int s = scale % 19; + if (s) + { + wide_int wm = wi::uhwi (pow10s[s - 1], w.get_precision ()); + w = wi::umul (w, wm, &ovf); + if (ovf) + scale = 0; + } + scale /= 19; + wide_int wm = wi::uhwi (pow10s[18], w.get_precision ()); + while (scale) + { + if (scale & 1) + { + w = wi::umul (w, wm, &ovf); + if (ovf) + break; + } + scale >>= 1; + if (!scale) + break; + wm = wi::umul (wm, wm, &ovf); + if (ovf) + break; + } + if (ovf) + { + *fail = true; + if (isneg) + return wi::set_bit_in_zero (precision - 1, precision); + else + return ~wi::set_bit_in_zero (precision - 1, precision); + } + if (isneg) + w = -w; + } + return w; } /* Perform the decimal floating point operation described by CODE. |