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-rw-r--r--ports/sysdeps/unix/alpha/sysdep.S66
1 files changed, 66 insertions, 0 deletions
diff --git a/ports/sysdeps/unix/alpha/sysdep.S b/ports/sysdeps/unix/alpha/sysdep.S
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+/* Copyright (C) 1993, 1996, 1998, 2002, 2003, 2004, 2012
+ Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Brendan Kehoe (brendan@zen.org).
+
+ 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#include <features.h>
+
+#if defined(PIC)
+ /* Put this at the end of libc's text segment so that all of
+ the direct branches from the syscalls are forward, and
+ thus predicted not taken. */
+ .section .text.last, "ax", @progbits
+#else
+ .text
+#endif
+
+#ifndef NOT_IN_libc
+# define SYSCALL_ERROR_ERRNO __libc_errno
+#else
+# define SYSCALL_ERROR_ERRNO errno
+#endif
+
+ .align 4
+ .globl __syscall_error
+ .ent __syscall_error
+__syscall_error:
+ /* When building a shared library, we branch here without having
+ loaded the GP. Nor, since it was a direct branch, have we
+ loaded PV with our address.
+
+ When building a static library, we tail call here from another
+ object file, possibly with a different GP, and must return with
+ the GP of our caller in place so that linker relaxation works.
+
+ Both issues are solved by computing the GP into T1 instead of
+ clobbering the traditional GP register. */
+ .prologue 0
+ mov v0, t0
+ br t1, 1f
+1: ldah t1, 0(t1) !gpdisp!1
+ call_pal PAL_rduniq
+
+ lda t1, 0(t1) !gpdisp!1
+ ldq t1, SYSCALL_ERROR_ERRNO(t1) !gottprel
+ addq v0, t1, t1
+ lda v0, -1
+
+ stl t0, 0(t1)
+ ret
+
+ .end __syscall_error