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author | Szabolcs Nagy <nsz@port70.net> | 2013-08-15 10:14:46 +0000 |
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committer | Szabolcs Nagy <nsz@port70.net> | 2013-08-15 10:14:46 +0000 |
commit | c599f4f4d705ba215a2672b92baa1c29d9dd0735 (patch) | |
tree | f9931ee00f59bae9aba69b9dbcff18a5c1613018 /src/math/x86_64 | |
parent | cd18dc8525a275323819ac4c7826cc3404202f7b (diff) | |
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math: fix asin, atan, log1p, tanh to raise underflow on subnormal
for these functions f(x)=x for small inputs, because f(0)=0 and
f'(0)=1, but for subnormal values they should raise the underflow
flag (required by annex F), if they are approximated by a polynomial
around 0 then spurious underflow should be avoided (not required by
annex F)
all these functions should raise inexact flag for small x if x!=0,
but it's not required by the standard and it does not seem a worthy
goal, so support for it is removed in some cases.
raising underflow:
- x*x may not raise underflow for subnormal x if FLT_EVAL_METHOD!=0
- x*x may raise spurious underflow for normal x if FLT_EVAL_METHOD==0
- in case of double subnormal x, store x as float
- in case of float subnormal x, store x*x as float
Diffstat (limited to 'src/math/x86_64')
0 files changed, 0 insertions, 0 deletions