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-rw-r--r--libc/sysdeps/linux/alpha/Makefile.arch4
-rw-r--r--libc/sysdeps/linux/alpha/syscall.S71
2 files changed, 73 insertions, 2 deletions
diff --git a/libc/sysdeps/linux/alpha/Makefile.arch b/libc/sysdeps/linux/alpha/Makefile.arch
index 91636c71a..4d33cef26 100644
--- a/libc/sysdeps/linux/alpha/Makefile.arch
+++ b/libc/sysdeps/linux/alpha/Makefile.arch
@@ -5,10 +5,10 @@
# Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
#
-CSRC := sysdep.c #brk.c
+CSRC := sysdep.c
SSRC := \
__longjmp.S brk.S bsd-_setjmp.S bsd-setjmp.S clone.S \
- divl.S divq.S reml.S remq.S setjmp.S
+ divl.S divq.S reml.S remq.S setjmp.S syscall.S
include $(top_srcdir)libc/sysdeps/linux/Makefile.commonarch
diff --git a/libc/sysdeps/linux/alpha/syscall.S b/libc/sysdeps/linux/alpha/syscall.S
new file mode 100644
index 000000000..1ccb5815f
--- /dev/null
+++ b/libc/sysdeps/linux/alpha/syscall.S
@@ -0,0 +1,71 @@
+/* Copyright (C) 1996 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <features.h>
+#include <asm/regdef.h>
+#include <asm/pal.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)
+ *
+ * syscall_number = the index of the system call we're invoking
+ * arg1-arg5 = up to 5 integer arguments to the system call
+ *
+ * We need to do some arg shifting: the kernel expects the
+ * syscall number in v0 and the first five args in a0-a4.
+ *
+ */
+
+.globl __syscall;
+.align 4;
+.ent __syscall, 0;
+__syscall:
+.frame sp, 0, ra
+ .prologue 0
+
+ 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
+
+ call_pal PAL_callsys /* Invoke system call */
+ bne a3, $error
+ ret
+
+$error:
+ br gp, 2f
+2: ldgp gp, 0(gp)
+ jmp zero,__syscall_error
+
+.end __syscall
+
+weak_alias (__syscall, syscall)