glibc/sysdeps/ia64/start.S

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/* Copyright (C) 1999-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Written by Jes Sorensen, <Jes.Sorensen@cern.ch>, April 1999.
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.
In addition to the permissions in the GNU Lesser General Public
License, the Free Software Foundation gives you unlimited
permission to link the compiled version of this file with other
programs, and to distribute those programs without any restriction
coming from the use of this file. (The GNU Lesser General Public
License restrictions do apply in other respects; for example, they
cover modification of the file, and distribution when not linked
into another program.)
Note that people who make modified versions of this file are not
obligated to grant this special exception for their modified
versions; it is their choice whether to do so. The GNU Lesser
General Public License gives permission to release a modified
version without this exception; this exception also makes it
possible to release a modified version which carries forward this
exception.
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
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <asm/unistd.h>
#include <asm/fpu.h>
/*
* Arguments for __libc_start_main:
* out0: main
* out1: argc
* out2: argv
* out3: init
* out4: fini
* out5: rtld_fini
* out6: stack_end
*/
.align 32
.global _start
.proc _start
.type _start,@function
_start:
.prologue
.save rp, r0
.body
.prologue
{ .mlx
alloc r2 = ar.pfs,0,0,7,0
movl r3 = FPSR_DEFAULT
}
{ .mlx
adds out2 = 16, sp /* get address of argc value */
movl gp = @gprel(0f)
;;
}
0: { .mmi
ld8 out1 = [out2], 8 /* load argc and move out2 to become argv */
mov.m r10 = ar.bsp /* fetch rbs base address */
mov r9 = ip
;;
}
{ .mii
mov ar.fpsr = r3
sub gp = r9, gp /* back-compute gp value */
adds out6 = 16, sp /* highest non-environment stack address */
;;
}
{
addl r11 = @ltoff(__libc_ia64_register_backing_store_base), gp
addl out0 = @ltoff(@fptr(main)), gp
addl out3 = @ltoff(@fptr(__libc_csu_init)), gp
;;
}
{ .mmi
ld8 r3 = [r11] /* pointer to __libc_ia64_register_backing_store_base */
ld8 out0 = [out0] /* pointer to `main' function descriptor */
addl out4 = @ltoff(@fptr(__libc_csu_fini)), gp
;;
}
{ .mmi
ld8 out3 = [out3] /* pointer to `init' function descriptor */
ld8 out4 = [out4] /* pointer to `fini' function descriptor */
nop 0
}
.body
{ .mib
st8 [r3] = r10
mov out5 = ret0 /* dynamic linker destructor */
br.call.sptk.few rp = __libc_start_main
}
{ .mib
break 0 /* break miserably if we ever return */
}
.endp _start
/* 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
.common __libc_ia64_register_backing_store_base, 8, 8