Hi,
You can try with foreign primops, it should be faster than the FFI:
In IsDoubleNanPrim.s:
.global isDoubleNan_prim
isDoubleNan_prim:
xor %rbx,%rbx
ucomisd %xmm1, %xmm1
lahf
testb $68, %ah
jnp .Lout
mov $1, %rbx
.Lout:
jmp * (%rbp)
In IsDoubleNan.hs:
{-# LANGUAGE
On 03/06/2018 10:43 AM, Brandon Allbery wrote:
> I'd in general expect good C code to optimize a little better; and in
> particular, decomposing an IEEE float is almost certainly more expensive in
> Haskell than in C, because unions let you cheat. (And I recall looking at
> the implementation of
I'd in general expect good C code to optimize a little better; and in
particular, decomposing an IEEE float is almost certainly more expensive in
Haskell than in C, because unions let you cheat. (And I recall looking at
the implementation of decodeFloat once; it's significantly longer than that
On 03/05/2018 10:23 PM, Brandon Allbery wrote:
> If the FFI version is done with "safe", consider using "unsafe" instead.
> There are technical reasons why this is slightly incorrect, but unless
> you're fiddling with the CPU's FP control flags they're mostly irrelevant
> and you can treat isNaN
If the FFI version is done with "safe", consider using "unsafe" instead.
There are technical reasons why this is slightly incorrect, but unless
you're fiddling with the CPU's FP control flags they're mostly irrelevant
and you can treat isNaN as pure and non-side-effectful, significantly
reducing
