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/* Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Written by Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de>,
December 1995.
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 <sysdeps/unix/sysdep.h>
/* For Linux we can use the system call table in the header file
/usr/include/asm/unistd.h
of the kernel. But these symbols do not follow the SYS_* syntax
so we have to redefine the `SYS_ify' macro here. */
#undef SYS_ify
#ifdef __STDC__
# define SYS_ify(syscall_name) __NR_##syscall_name
#else
# define SYS_ify(syscall_name) __NR_/**/syscall_name
#endif
#ifdef ASSEMBLER
/* Define an entry point visible from C. */
#define ENTRY(name) \
.globl name; \
.type name, @function; \
.align 4; \
C_LABEL(name) \
CALL_MCOUNT
#undef END
#define END(name) .size name, . - name
/* If compiled for profiling, call `_mcount' at the start of each function. */
#ifdef PROF
/* The mcount code relies on a normal frame pointer being on the stack
to locate our caller, so push one just for its benefit. */
#define CALL_MCOUNT \
move.l %fp, -(%sp); move.l %sp, %fp; \
jbsr JUMPTARGET (_mcount); \
move.l (%sp)+, %fp;
#else
#define CALL_MCOUNT /* Do nothing. */
#endif
#ifdef PIC
#define JUMPTARGET(name) name##@PLTPC
#else
#define JUMPTARGET(name) name
#endif
/* Since C identifiers are not normally prefixed with an underscore
on this system, the asm identifier `syscall_error' intrudes on the
C name space. Make sure we use an innocuous name. */
#define syscall_error __syscall_error
/* Linux uses a negative return value to indicate syscall errors, unlike
most Unices, which use the condition codes' carry flag.
Since version 2.1 the return value of a system call might be negative
even if the call succeeded. E.g., the `lseek' system call might return
a large offset. Therefore we must not anymore test for < 0, but test
for a real error by making sure the value in %d0 is a real error
number. Linus said he will make sure the no syscall returns a value
in -1 .. -4095 as a valid result so we can savely test with -4096. */
#define PSEUDO(name, syscall_name, args) \
.text; \
ENTRY (name) \
DO_CALL (&SYS_ify (syscall_name), args); \
moveq.l &-4096, %d1; \
cmp.l %d1, %d0; \
jcc syscall_error
#undef PSEUDO_END
#define PSEUDO_END(name) \
SYSCALL_ERROR_HANDLER; \
END (name)
#ifdef PIC
/* Store (- %d0) into errno through the GOT. */
#ifdef _LIBC_REENTRANT
#define SYSCALL_ERROR_HANDLER \
syscall_error: \
move.l (errno@GOTPC, %pc), %a0; \
neg.l %d0; \
move.l %d0, (%a0); \
move.l %d0, -(%sp); \
jbsr __errno_location@PLTPC; \
move.l (%sp)+, (%a0); \
move.l &-1, %d0; \
/* Copy return value to %a0 for syscalls that are declared to return \
a pointer (e.g., mmap). */ \
move.l %d0, %a0; \
rts;
#else
#define SYSCALL_ERROR_HANDLER \
syscall_error: \
move.l (errno@GOTPC, %pc), %a0; \
neg.l %d0; \
move.l %d0, (%a0); \
move.l &-1, %d0; \
/* Copy return value to %a0 for syscalls that are declared to return \
a pointer (e.g., mmap). */ \
move.l %d0, %a0; \
rts;
#endif /* _LIBC_REENTRANT */
#else
#define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
#endif /* PIC */
/* Linux takes system call arguments in registers:
syscall number %d0 call-clobbered
arg 1 %d1 call-clobbered
arg 2 %d2 call-saved
arg 3 %d3 call-saved
arg 4 %d4 call-saved
arg 5 %d5 call-saved
The stack layout upon entering the function is:
20(%sp) Arg# 5
16(%sp) Arg# 4
12(%sp) Arg# 3
8(%sp) Arg# 2
4(%sp) Arg# 1
(%sp) Return address
(Of course a function with say 3 arguments does not have entries for
arguments 4 and 5.)
Separate move's are faster than movem, but need more space. Since
speed is more important, we don't use movem. Since %a0 and %a1 are
scratch registers, we can use them for saving as well. */
#define DO_CALL(syscall, args) \
move.l syscall, %d0; \
DOARGS_##args \
trap &0; \
UNDOARGS_##args
#define DOARGS_0 /* No arguments to frob. */
#define UNDOARGS_0 /* No arguments to unfrob. */
#define _DOARGS_0(n) /* No arguments to frob. */
#define DOARGS_1 _DOARGS_1 (4)
#define _DOARGS_1(n) move.l n(%sp), %d1; _DOARGS_0 (n)
#define UNDOARGS_1 UNDOARGS_0
#define DOARGS_2 _DOARGS_2 (8)
#define _DOARGS_2(n) move.l %d2, %a0; move.l n(%sp), %d2; _DOARGS_1 (n-4)
#define UNDOARGS_2 UNDOARGS_1; move.l %a0, %d2
#define DOARGS_3 _DOARGS_3 (12)
#define _DOARGS_3(n) move.l %d3, %a1; move.l n(%sp), %d3; _DOARGS_2 (n-4)
#define UNDOARGS_3 UNDOARGS_2; move.l %a1, %d3
#define DOARGS_4 _DOARGS_4 (16)
#define _DOARGS_4(n) move.l %d4, -(%sp); move.l n+4(%sp), %d4; _DOARGS_3 (n)
#define UNDOARGS_4 UNDOARGS_3; move.l (%sp)+, %d4
#define DOARGS_5 _DOARGS_5 (20)
#define _DOARGS_5(n) move.l %d5, -(%sp); move.l n+4(%sp), %d5; _DOARGS_4 (n)
#define UNDOARGS_5 UNDOARGS_4; move.l (%sp)+, %d5
#define ret rts
#if 0 /* Not used by Linux */
#define r0 %d0
#define r1 %d1
#define MOVE(x,y) movel x , y
#endif
#endif /* ASSEMBLER */
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