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![]() The float32_exp2 function is computing wrong exponent of 2.
For example, with the following set of values {0.1, 2.0, 2.0, -1.0},
the expected output would be {1.071773, 4.000000, 4.000000, 0.500000}.
Instead, the function is computing {1.119102, 3.382044, 3.382044, -0.191022}
Looking at the code, the float32_exp2() attempts to do this
2 3 4 5 n
x x x x x x x
e = 1 + --- + --- + --- + --- + --- + ... + --- + ...
1! 2! 3! 4! 5! n!
But because of the typo it ends up doing
x x x x x x x
e = 1 + --- + --- + --- + --- + --- + ... + --- + ...
1! 2! 3! 4! 5! n!
This is because instead of the xnp which holds the numerator, parts_muladd
is using the xp which is just 'x'. Commit '572c4d862ff2' refactored this
function, and mistakenly used xp instead of xnp.
Cc: qemu-stable@nongnu.org
Fixes:
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.. | ||
meson.build | ||
softfloat-parts-addsub.c.inc | ||
softfloat-parts.c.inc | ||
softfloat-specialize.c.inc | ||
softfloat.c |