musl/arch/riscv64/crt_arch.h
Rich Felker 0a48860c27 add riscv64 architecture support
Author: Alex Suykov <alex.suykov@gmail.com>
Author: Aric Belsito <lluixhi@gmail.com>
Author: Drew DeVault <sir@cmpwn.com>
Author: Michael Clark <mjc@sifive.com>
Author: Michael Forney <mforney@mforney.org>
Author: Stefan O'Rear <sorear2@gmail.com>

This port has involved the work of many people over several years. I
have tried to ensure that everyone with substantial contributions has
been credited above; if any omissions are found they will be noted
later in an update to the authors/contributors list in the COPYRIGHT
file.

The version committed here comes from the riscv/riscv-musl repo's
commit 3fe7e2c75df78eef42dcdc352a55757729f451e2, with minor changes by
me for issues found during final review:

- a_ll/a_sc atomics are removed (according to the ISA spec, lr/sc
  are not safe to use in separate inline asm fragments)

- a_cas[_p] is fixed to be a memory barrier

- the call from the _start assembly into the C part of crt1/ldso is
  changed to allow for the possibility that the linker does not place
  them nearby each other.

- DTP_OFFSET is defined correctly so that local-dynamic TLS works

- reloc.h LDSO_ARCH logic is simplified and made explicit.

- unused, non-functional crti/n asm files are removed.

- an empty .sdata section is added to crt1 so that the
  __global_pointer reference is resolvable.

- indentation style errors in some asm files are fixed.
2019-06-14 17:13:05 -04:00

20 lines
379 B
C

__asm__(
".section .sdata,\"aw\"\n"
".text\n"
".global " START "\n"
".type " START ",%function\n"
START ":\n"
".weak __global_pointer$\n"
".hidden __global_pointer$\n"
".option push\n"
".option norelax\n\t"
"lla gp, __global_pointer$\n"
".option pop\n\t"
"mv a0, sp\n"
".weak _DYNAMIC\n"
".hidden _DYNAMIC\n\t"
"lla a1, _DYNAMIC\n\t"
"andi sp, sp, -16\n\t"
"tail " START "_c"
);