cosmopolitan/libc/nexgen32e/gc.S
Justine Tunney 414667b1c9
Get TEST_LIBC_STR passing on AARCH64
It's now possible to run commands like:

    make -j8 m=aarch64 o/aarch64/test/libc/str

Which will cross-compile and run the test suites in a qemu-aarch64
binary that's vendored in the third_party/qemu/ folder within your
x86_64 build environment.
2023-05-12 18:09:23 -07:00

61 lines
2.8 KiB
ArmAsm

/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
Permission to use, copy, modify, and/or distribute this software for
any purpose with or without fee is hereby granted, provided that the
above copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.
*/
#include "libc/macros.internal.h"
#include "libc/dce.h"
#include "libc/notice.inc"
nop
// Invokes deferred function calls.
//
// This offers behavior similar to std::unique_ptr. Functions
// overwrite their return addresses jumping here, and pushing
// exactly one entry on the shadow stack below. Functions may
// repeat that process multiple times, in which case the body
// of this gadget loops and unwinds as a natural consequence.
//
// @param rax,rdx,xmm0,xmm1,st0,st1 is return value
// @see test/libc/runtime/gc_test.c
// @threadsafe
__gc: mov %fs:0,%rcx // __get_tls()
mov 0x18(%rcx),%rcx // tls::garbages
decl (%rcx) // ++g->i
mov (%rcx),%r8d // r8 = g->i
mov 8(%rcx),%r9 // r9 = g->p
js 9f
shl $5,%r8
lea (%r9,%r8),%r8
mov 8(%r8),%r9
mov 16(%r8),%rdi
push 24(%r8)
push %rbp
mov %rsp,%rbp
sub $32,%rsp
mov %rax,-8(%rbp)
mov %rdx,-16(%rbp)
movdqa %xmm0,-32(%rbp)
call *%r9
movdqa -32(%rbp),%xmm0
mov -16(%rbp),%rdx
mov -8(%rbp),%rax
leave
ret
9: ud2
nop
.endfn __gc,globl,hidden