Added x64 assembly compilation

[Amaras]

And here we go again with X64 Assembly.

There was a little annoyance this time: the way we programmed the assembly required the compilation to use the link flag -no-pie. As such, to prevent environment duplication, I elected to add the link flag to all the executables.

Apart from this, compilation was not affected, and all executables compile successfully on my Linux machine.

We really should set up a Windows environment to check whether it works as intended there, though.

[ShadowMitia]

I have executables that segfault on my machine, the ones that do run:

• cooley_tukey
• monte_carlo_integration
• verlet_integration

Let me know if you want me to open an issue, or if you want more info.

[Amaras]

The only segfault I could reproduce on my machine is for forward_euler_method, which does so in __printf, probably because of a bad formatting in results_loop.

I will need more detail for the others, and it is probably not my responsibility. I had already noticed the segfault in some of the x64 implementations, but did not take the time to report them, I think.

[ShadowMitia]

I might've found a way to pass it only to specific languages.
I found the information here: https://scons.org/doc/production/HTML/scons-man.html#f-ParseFlags, basically you can use -Wl, to ass stuff to the linker.
It might not be very cross-platform though... Should support gcc/clang at least.

[ShadowMitia]

The only segfault I could reproduce on my machine is for forward_euler_method, which does so in __printf, probably because of a bad formatting in results_loop.

I will need more detail for the others, and it is probably not my responsibility. I had already noticed the segfault in some of the x64 implementations, but did not take the time to report them, I think.

I've run some quick tests, it does seem to also be coming from printf formatting as well on my end, but it happens on more examples. I'll open an issue for it.

[Amaras]

It might not be very cross-platform though... Should support gcc/clang at least.

We basically don't matter care if it's cross platform at this point, do we? We already forced the use of gcc, gnulink, next will be g++ and the GNU X86_64 assembler.

[ShadowMitia]

For now I think you're right

[Amaras]

Alright, @PeanutbutterWarrior and I decided on Discord here to give up on trying to build x86-64 assembly on Windows.
The linker seemed to outright ignore the -no-pie option, as well as --no-pie, -static and --static.

Commit 12350c5 fixed a bug in @ShadowMitia's proposal that made it impossible to link correctly. However, the expected behaviour was achieved by using the LINKFLAGS argument in the env.X64 calls. (The commit also simplifies the SConstruct so that's always a plus).

As such, I think this PR is ready to merge, just possibly waiting for the approval of another maintainer.

[leios]

This looks great! Thanks for the work here!