summaryrefslogtreecommitdiff
path: root/sysdeps/unix/sysv/linux/m68k/sysdep.h
blob: 39b7bda1bbecd994ce662e3667fc5d9e1fea8ca6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
/* Copyright (C) 1996, 1997, 1998, 2000 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., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <sysdeps/unix/sysdep.h>
#include <sysdeps/m68k/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__

/* 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 -4095.  */

/* We don't want the label for the error handler to be visible in the symbol
   table when we define it here.  */
#ifdef PIC
#define SYSCALL_ERROR_LABEL .Lsyscall_error
#else
#define SYSCALL_ERROR_LABEL __syscall_error
#endif

#undef PSEUDO
#define	PSEUDO(name, syscall_name, args)				      \
  .text;								      \
  ENTRY (name)								      \
    DO_CALL (syscall_name, args);					      \
    cmp.l &-4095, %d0;							      \
    jcc SYSCALL_ERROR_LABEL

#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_LABEL:							      \
    neg.l %d0;								      \
    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 /* !_LIBC_REENTRANT */
#define SYSCALL_ERROR_HANDLER						      \
SYSCALL_ERROR_LABEL:							      \
    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_name, args)			      		      \
    move.l &SYS_ify(syscall_name), %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

#else /* not __ASSEMBLER__ */

/* Define a macro which expands into the inline wrapper code for a system
   call.  */
#undef INLINE_SYSCALL
#define INLINE_SYSCALL(name, nr, args...)		\
  ({ unsigned int _sys_result;				\
     {							\
       LOAD_ARGS_##nr (args)				\
       register int _d0 asm ("%d0") = __NR_##name;	\
       asm volatile ("trap #0"				\
		     : "=d" (_d0)			\
		     : "0" (_d0) ASM_ARGS_##nr		\
		     : "d0", "memory");			\
       _sys_result = _d0;				\
     }							\
     if (_sys_result >= (unsigned int) -4095)		\
       {						\
	 __set_errno (-_sys_result);			\
	 _sys_result = (unsigned int) -1;		\
       }						\
     (int) _sys_result; })

#define LOAD_ARGS_0()
#define ASM_ARGS_0
#define LOAD_ARGS_1(a1)				\
  register int _d1 asm ("d1") = (int) (a1);	\
  LOAD_ARGS_0 ()
#define ASM_ARGS_1	ASM_ARGS_0, "d" (_d1)
#define LOAD_ARGS_2(a1, a2)			\
  register int _d2 asm ("d2") = (int) (a2);	\
  LOAD_ARGS_1 (a1)
#define ASM_ARGS_2	ASM_ARGS_1, "d" (_d2)
#define LOAD_ARGS_3(a1, a2, a3)			\
  register int _d3 asm ("d3") = (int) (a3);	\
  LOAD_ARGS_2 (a1, a2)
#define ASM_ARGS_3	ASM_ARGS_2, "d" (_d3)
#define LOAD_ARGS_4(a1, a2, a3, a4)		\
  register int _d4 asm ("d4") = (int) (a4);	\
  LOAD_ARGS_3 (a1, a2, a3)
#define ASM_ARGS_4	ASM_ARGS_3, "d" (_d4)
#define LOAD_ARGS_5(a1, a2, a3, a4, a5)		\
  register int _d5 asm ("d5") = (int) (a5);	\
  LOAD_ARGS_4 (a1, a2, a3, a4)
#define ASM_ARGS_5	ASM_ARGS_4, "d" (_d5)

#endif /* not __ASSEMBLER__ */