Blame sysdeps/unix/alpha/sysdep.S

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/* Copyright (C) 1993-2018 Free Software Foundation, Inc.
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   This file is part of the GNU C Library.
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   Contributed by Brendan Kehoe (brendan@zen.org).
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library.  If not, see
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   <http://www.gnu.org/licenses/>.  */
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#include <sysdep.h>
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#include <features.h>
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#if defined(PIC)
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	/* Put this at the end of libc's text segment so that all of
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	   the direct branches from the syscalls are forward, and
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	   thus predicted not taken.  */
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	.section .text.last, "ax", @progbits
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#else
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	.text
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#endif
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#if IS_IN (libc)
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# define SYSCALL_ERROR_ERRNO __libc_errno
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#else
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# define SYSCALL_ERROR_ERRNO errno
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#endif
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	.align 4
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	.globl	__syscall_error
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	.ent	__syscall_error
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__syscall_error:
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	/* When building a shared library, we branch here without having
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	   loaded the GP.  Nor, since it was a direct branch, have we
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	   loaded PV with our address.
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	   When building a static library, we tail call here from another
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	   object file, possibly with a different GP, and must return with
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	   the GP of our caller in place so that linker relaxation works.
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	   Both issues are solved by computing the GP into T1 instead of
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	   clobbering the traditional GP register.  */
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	.prologue 0
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	mov	v0, t0
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	br	t1, 1f
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1:	ldah	t1, 0(t1) !gpdisp!1
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	call_pal PAL_rduniq
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	lda	t1, 0(t1) !gpdisp!1
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	ldq	t1, SYSCALL_ERROR_ERRNO(t1) !gottprel
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	addq	v0, t1, t1
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	lda	v0, -1
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	stl	t0, 0(t1)
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	ret
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	.end __syscall_error