From dba942c80dc2cfa5768a856fff98e22a755fdd27 Mon Sep 17 00:00:00 2001 From: Waldemar Brodkorb Date: Tue, 4 Oct 2016 06:51:35 +0200 Subject: add experimental aarch64 support Ported over from GNU C Library and runtime tested in Qemu. --- libc/sysdeps/linux/aarch64/crt1.S | 89 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+) create mode 100644 libc/sysdeps/linux/aarch64/crt1.S (limited to 'libc/sysdeps/linux/aarch64/crt1.S') diff --git a/libc/sysdeps/linux/aarch64/crt1.S b/libc/sysdeps/linux/aarch64/crt1.S new file mode 100644 index 000000000..09d0327ac --- /dev/null +++ b/libc/sysdeps/linux/aarch64/crt1.S @@ -0,0 +1,89 @@ +/* Copyright (C) 1995-2016 Free Software Foundation, Inc. + + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library. If not, see + . */ + +/* This is the canonical entry point, usually the first thing in the text + segment. + + Note that the code in the .init section has already been run. + This includes _init and _libc_init + + + At this entry point, most registers' values are unspecified, except: + + x0 Contains a function pointer to be registered with `atexit'. + This is how the dynamic linker arranges to have DT_FINI + functions called for shared libraries that have been loaded + before this code runs. + + sp The stack contains the arguments and environment: + 0(sp) argc + 8(sp) argv[0] + ... + (8*argc)(sp) NULL + (8*(argc+1))(sp) envp[0] + ... + NULL + */ + + .text + .globl _start + .type _start,#function +_start: + /* Create an initial frame with 0 LR and FP */ + mov x29, #0 + mov x30, #0 + + /* Setup _fini in argument register */ + mov x5, x0 + + /* Load argc and a pointer to argv */ + ldr x1, [sp, #0] + add x2, sp, #8 + + /* Setup stack limit in argument register */ + mov x6, sp + +#ifdef __PIC__ + adrp x0, :got:main + ldr x0, [x0, #:got_lo12:main] + + adrp x3, :got:_init + ldr x3, [x3, #:got_lo12:_init] + + adrp x4, :got:_fini + ldr x4, [x4, #:got_lo12:_fini] +#else + /* Set up the other arguments in registers */ + ldr x0, =main + ldr x3, =_init + ldr x4, =_fini +#endif + + /* Let the libc call main and exit with its return code. */ + bl __uClibc_main + + /* should never get here....*/ + bl abort + + /* Define a symbol for the first piece of initialized data. */ + .data + .globl __data_start +__data_start: + .long 0 + .weak data_start + data_start = __data_start -- cgit v1.2.3