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authorRichard Henderson <rth@twiddle.net>2014-02-12 06:54:57 -0800
committerRichard Henderson <rth@twiddle.net>2014-02-12 07:00:06 -0800
commit68b7efaadb1b6045a56277ea62d324c20ac0b633 (patch)
tree07b51c9866373430373fb90b252d46c23cc1707e /sysdeps/unix/sysv/linux/alpha/syscall.S
parent8fd7b0d5591e59ed5cb3078b351bd49314a66cef (diff)
downloadglibc-68b7efaadb1b6045a56277ea62d324c20ac0b633.tar.gz
Relocate alpha from ports to libc
Also fixed the following whitespace nits to satisfy the push: sysdeps/alpha/alphaev6/memset.S:142: space before tab in indent. sysdeps/alpha/configure:1: new blank line at EOF. sysdeps/alpha/fpu/e_sqrt.c:126: space before tab in indent. sysdeps/alpha/preconfigure:1: new blank line at EOF. sysdeps/unix/sysv/linux/alpha/syscalls.list:1: new blank line at EOF.
Diffstat (limited to 'sysdeps/unix/sysv/linux/alpha/syscall.S')
-rw-r--r--sysdeps/unix/sysv/linux/alpha/syscall.S70
1 files changed, 70 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/alpha/syscall.S b/sysdeps/unix/sysv/linux/alpha/syscall.S
new file mode 100644
index 0000000000..b0088e5eca
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/alpha/syscall.S
@@ -0,0 +1,70 @@
+/* Copyright (C) 1996-2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by David Mosberger <davidm@azstarnet.com>, 1996.
+
+ 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>
+
+/*
+ * This is for COMPATIBILITY with Linux/x86 only. Linux/Alpha system
+ * calls return an error indication in a3. This allows arbitrary 64bit
+ * values to be returned in v0 (because negative values are not
+ * mistaken as error numbers). However, C allows only one value to
+ * be returned, so the interface below folds the error indication passed in
+ * a3 back into v0: it sets v0 to -errno if an error occurs. Thus,
+ * no negative 64bit numbers can be returned. To avoid this problem,
+ * use assembly stubs wherever possible/convenient.
+ *
+ * Usage:
+ *
+ * long syscall(syscall_number, arg1, arg2, arg3, arg4, arg5, arg6)
+ *
+ * syscall_number = the index of the system call we're invoking
+ * arg1-arg6 = up to 6 integer arguments to the system call
+ *
+ * We need to do some arg shifting: the kernel expects the
+ * syscall number in v0 and the first six args in a0-a5.
+ *
+ */
+
+
+LEAF(__syscall, 0)
+#ifdef PROF
+ ldgp gp, 0(pv)
+ .set noat
+ lda AT, _mcount
+ jsr AT, (AT), _mcount
+ .set at
+ .prologue 1
+#else
+ .prologue 0
+#endif
+
+ mov a0, v0 /* Syscall number -> v0 */
+ mov a1, a0 /* arg1-arg5 -> a0-a4 */
+ mov a2, a1
+ mov a3, a2
+ mov a4, a3
+ mov a5, a4
+ ldq a5,0(sp) /* arg6 -> a5 */
+
+ call_pal PAL_callsys /* Invoke system call */
+ bne a3, SYSCALL_ERROR_LABEL
+ ret
+
+PSEUDO_END(__syscall)
+
+weak_alias (__syscall, syscall)