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Date:      Tue, 15 Jan 2019 12:58:20 +0000
From:      Lorenzo Salvadore <phascolarctos@protonmail.ch>
To:        FreeBSD Questions <freebsd-questions@freebsd.org>
Subject:   Re: if userland in asm, no need for libc?
Message-ID:  <J_qTow5gXx1lin3NNGlIU4Bls-dwLhlD0FkHcPmPy5e1Yq4iAX5DL46C70nUHfeIgin4sJV7BsP1ydXJOmxZbPotYLmBbxfPPNptBTdF3II=@protonmail.ch>
In-Reply-To: <201901151224.x0FCOHbM016508@sdf.org>
References:  <201901151224.x0FCOHbM016508@sdf.org>

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> in continuum to my previous mail about libc;
> if the whole of userland and various other toolkits were written
> in assembly language, would there be no need for libc, that is
> if "c" were not needed to be supported at all?
> do assembly language programs have the capacity to make kernel
> calls directly? i.e., without going through any libraries?
> pardon my naive questions, i don't have a background in computer
> science nor enough self-training.

Yes, you can make kernel calls directly. See here for example:
https://www.freebsd.org/doc/en/books/developers-handbook/x86-system-calls.h=
tml

Still, I discourage you from using Assembly too much: it is not easy to wri=
te
in Assembly, don't use it if you can do what you want to do in a higher lev=
el
language. You should rather use Assembly only for low level interaction wit=
h
hardware or to optimize code when compilers do not already optimize enough
for your tastes/needs.

Lorenzo Salvadore.



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