| /* Copyright (C) 1996 Free Software Foundation, Inc. |
| Contributed by David Mosberger (davidm@azstarnet.com). |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Library General Public License as |
| published by the Free Software Foundation; either version 2 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 |
| Library General Public License for more details. |
| |
| You should have received a copy of the GNU Library General Public |
| License along with the GNU C Library; see the file COPYING.LIB. If |
| not, write to the Free Software Foundation, Inc., 675 Mass Ave, |
| Cambridge, MA 02139, USA. */ |
| |
| #include <sysdep.h> |
| |
| /* |
| * This is for COMPATIBILITY with Linux/x86 only. Linux/Alpha system |
| * calls return an error indication in a3. This allows to return |
| * arbitrary 64bit values in v0 (because negative values are not |
| * mistaken as error numbers). However, C allows to return only one |
| * value 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. |
| * |
| */ |
| |
| |
| LEAF(__syscall, 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 |
| |
| weak_alias(__syscall, syscall) |
