diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/e_expl.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-128ibm/e_expl.c | 34 |
1 files changed, 22 insertions, 12 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/e_expl.c b/sysdeps/ieee754/ldbl-128ibm/e_expl.c index 82363906b0..60229d5da8 100644 --- a/sysdeps/ieee754/ldbl-128ibm/e_expl.c +++ b/sysdeps/ieee754/ldbl-128ibm/e_expl.c @@ -70,11 +70,11 @@ static const long double C[] = { /* Smallest integer x for which e^x overflows. */ #define himark C[0] - 709.08956571282405153382846025171462914L, + 709.78271289338399678773454114191496482L, /* Largest integer x for which e^x underflows. */ #define lomark C[1] --744.44007192138121808966388925909996033L, +-744.44007192138126231410729844608163411L, /* 3x2^96 */ #define THREEp96 C[2] @@ -138,14 +138,12 @@ __ieee754_expl (long double x) if (isless (x, himark) && isgreater (x, lomark)) { int tval1, tval2, unsafe, n_i, exponent2; - long double x22, n, result, xl; - union ibm_extended_long_double ex2_u, scale_u; + long double x22, n, xl; + union ibm_extended_long_double ex2_u, scale_u, result; fenv_t oldenv; feholdexcept (&oldenv); -#ifdef FE_TONEAREST fesetround (FE_TONEAREST); -#endif n = __roundl (x*M_1_LN2); x = x-n*M_LN2_0; @@ -166,7 +164,7 @@ __ieee754_expl (long double x) * __expl_table[T_EXPL_RES2 + tval2]; n_i = (int)n; /* 'unsafe' is 1 iff n_1 != 0. */ - unsafe = fabsl(n_i) >= -LDBL_MIN_EXP - 1; + unsafe = abs (n_i) >= -LDBL_MIN_EXP - 1; ex2_u.ieee.exponent += n_i >> unsafe; /* Fortunately, there are no subnormal lowpart doubles in __expl_table, only normal values and zeros. @@ -204,7 +202,7 @@ __ieee754_expl (long double x) /* Return result. */ fesetenv (&oldenv); - result = x22 * ex2_u.d + ex2_u.d; + result.d = x22 * ex2_u.d + ex2_u.d; /* Now we can test whether the result is ultimate or if we are unsure. In the later case we should probably call a mpn based routine to give @@ -235,10 +233,22 @@ __ieee754_expl (long double x) return __ieee754_expl_proc2 (origx); } */ - if (!unsafe) - return result; - else - return result * scale_u.d; + if (unsafe) + { + /* The scale with denormal number might generated underflow for + first high double multiplication. The exception holding is + to avoid it. */ + if (result.ieee.exponent + scale_u.ieee.exponent + < IBM_EXTENDED_LONG_DOUBLE_BIAS) + { + feholdexcept (&oldenv); + result.d *= scale_u.d; + fesetenv (&oldenv); + } + else + result.d *= scale_u.d; + } + return result.d; } /* Exceptional cases: */ else if (isless (x, himark)) |