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@@ -0,0 +1,71 @@
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+/* Copyright (C) 1996 Free Software Foundation, Inc.
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+ This file is part of the GNU C Library.
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+ Contributed by David Mosberger <davidm@azstarnet.com>, 1996.
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+
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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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+
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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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+
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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, write to the Free
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+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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+ 02111-1307 USA. */
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+
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+#include <features.h>
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+#include <asm/regdef.h>
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+#include <asm/pal.h>
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+
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+/*
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+ * This is for COMPATIBILITY with Linux/x86 only. Linux/Alpha system
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+ * calls return an error indication in a3. This allows arbitrary 64bit
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+ * values to be returned in v0 (because negative values are not
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+ * mistaken as error numbers). However, C allows only one value to
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+ * be returned, so the interface below folds the error indication passed in
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+ * a3 back into v0: it sets v0 to -errno if an error occurs. Thus,
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+ * no negative 64bit numbers can be returned. To avoid this problem,
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+ * use assembly stubs wherever possible/convenient.
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+ *
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+ * Usage:
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+ *
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+ * long syscall(syscall_number, arg1, arg2, arg3, arg4, arg5)
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+ *
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+ * syscall_number = the index of the system call we're invoking
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+ * arg1-arg5 = up to 5 integer arguments to the system call
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+ *
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+ * We need to do some arg shifting: the kernel expects the
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+ * syscall number in v0 and the first five args in a0-a4.
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+ *
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+ */
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+
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+.globl __syscall;
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+.align 4;
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+.ent __syscall, 0;
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+__syscall:
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+.frame sp, 0, ra
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+ .prologue 0
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+
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+ mov a0, v0 /* Syscall number -> v0 */
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+ mov a1, a0 /* arg1-arg5 -> a0-a4 */
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+ mov a2, a1
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+ mov a3, a2
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+ mov a4, a3
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+ mov a5, a4
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+
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+ call_pal PAL_callsys /* Invoke system call */
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+ bne a3, $error
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+ ret
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+
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+$error:
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+ br gp, 2f
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+2: ldgp gp, 0(gp)
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+ jmp zero,__syscall_error
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+
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+.end __syscall
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+
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+weak_alias (__syscall, syscall)
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Mike Frysinger