Re: musl-cross-make build script.

[Szabolcs Nagy <nsz@port70.net>]

* Szabolcs Nagy <nsz@port70.net> [2017-02-18 13:53:01 +0100]:
> in a triplet "armv8" means the armv8 architecture in
> 32bit execution state (which arm calls aarch32) and
> that is backward compatible (and almost identical to)
> armv7 (at least the -a profile, armv8-m and armv7-m
> have more differences afaik)
> 
> in a triplet "aarch64" means the armv8 architecture in
> 64bit execution state.
> 
> so if you configure for armv8l-linux-musleabihf you
> get a toolchain that follows a 32bit arm abi and uses
> a 32bit arm isa (thumb or arm like with armv7).
> 
> the 64bit triplet is aarch64-linux-musl (there is no
> soft float abi nor eabi suffix), there is an ilp32
> abi for aarch64 which uses 64bit isa (like x32) which
> is not supported by musl, and a bigendian variant
> which can be configured with "aarch64_be" (but not
> used in practice i think).

one more note: there are various isa levels and
extensions, e.g.

 --with-arch=armv8.2-a+crypto+fp16

will configure for armv8.2-a isa level with the
optional crypto and 16bit float instructions enabled.
(this affects both 32bit and 64bit arm isas)

there is no softfloat abi, but you can still compile
something without float instructions using cflag like

 -march=armv8-a+nofp

(the -mgeneral-regs-only flag works too, but +noXXX
is a generic way to turn extensions off.. so there
is a zoo of variants, but binary distros will care
about the baseline armv8-a only i guess)