1/* Definitions of target machine for GNU compiler, NetBSD/arm ELF version.
2   Copyright (C) 2002-2015 Free Software Foundation, Inc.
3   Contributed by Wasabi Systems, Inc.
4
5   This file is part of GCC.
6
7   GCC is free software; you can redistribute it and/or modify it
8   under the terms of the GNU General Public License as published
9   by the Free Software Foundation; either version 3, or (at your
10   option) any later version.
11
12   GCC is distributed in the hope that it will be useful, but WITHOUT
13   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
15   License for more details.
16
17   Under Section 7 of GPL version 3, you are granted additional
18   permissions described in the GCC Runtime Library Exception, version
19   3.1, as published by the Free Software Foundation.
20
21   You should have received a copy of the GNU General Public License and
22   a copy of the GCC Runtime Library Exception along with this program;
23   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
24   <http://www.gnu.org/licenses/>.  */
25
26/* Run-time Target Specification.  */
27
28/* arm.h defaults to ARM6 CPU.  */
29
30/* This defaults us to little-endian.  */
31#ifndef TARGET_ENDIAN_DEFAULT
32#define TARGET_ENDIAN_DEFAULT 0
33#endif
34
35#undef MULTILIB_DEFAULTS
36
37/* Default it to use ATPCS with soft-VFP.  */
38#undef TARGET_DEFAULT
39#define TARGET_DEFAULT			\
40  (MASK_APCS_FRAME			\
41   | TARGET_ENDIAN_DEFAULT)
42
43#undef ARM_DEFAULT_ABI
44#define ARM_DEFAULT_ABI ARM_ABI_ATPCS
45
46#define TARGET_OS_CPP_BUILTINS()	\
47  do					\
48    {					\
49      NETBSD_OS_CPP_BUILTINS_ELF();	\
50    }					\
51  while (0)
52
53#undef SUBTARGET_CPP_SPEC
54#define SUBTARGET_CPP_SPEC NETBSD_CPP_SPEC
55
56#undef SUBTARGET_EXTRA_ASM_SPEC
57#define SUBTARGET_EXTRA_ASM_SPEC	\
58  "-matpcs %{fpic|fpie:-k} %{fPIC|fPIE:-k}"
59
60/* Default to full VFP if -mfloat-abi=hard is specified.  */
61#undef SUBTARGET_ASM_FLOAT_SPEC
62#define SUBTARGET_ASM_FLOAT_SPEC	\
63  "%{mfloat-abi=hard:{!mfpu=*:-mfpu=vfp}}"
64
65#undef SUBTARGET_EXTRA_SPECS
66#define SUBTARGET_EXTRA_SPECS				\
67  { "subtarget_extra_asm_spec",	SUBTARGET_EXTRA_ASM_SPEC }, \
68  { "subtarget_asm_float_spec", SUBTARGET_ASM_FLOAT_SPEC }, \
69  { "netbsd_link_spec",		NETBSD_LINK_SPEC_ELF },	\
70  { "netbsd_entry_point",	NETBSD_ENTRY_POINT },
71
72#define NETBSD_ENTRY_POINT "__start"
73
74#undef LINK_SPEC
75#define LINK_SPEC \
76  "-X %{mbig-endian:-EB} %{mlittle-endian:-EL} \
77   %(netbsd_link_spec)"
78
79/* Make GCC agree with <machine/ansi.h>.  */
80
81#undef SIZE_TYPE
82#define SIZE_TYPE "long unsigned int"
83
84#undef PTRDIFF_TYPE
85#define PTRDIFF_TYPE "long int"
86
87/* We don't have any limit on the length as out debugger is GDB.  */
88#undef DBX_CONTIN_LENGTH
89
90/* NetBSD does its profiling differently to the Acorn compiler. We
91   don't need a word following the mcount call; and to skip it
92   requires either an assembly stub or use of fomit-frame-pointer when
93   compiling the profiling functions.  Since we break Acorn CC
94   compatibility below a little more won't hurt.  */
95
96#undef ARM_FUNCTION_PROFILER
97#define ARM_FUNCTION_PROFILER(STREAM,LABELNO)		\
98{							\
99  asm_fprintf (STREAM, "\tmov\t%Rip, %Rlr\n");		\
100  asm_fprintf (STREAM, "\tbl\t__mcount%s\n",		\
101	       (TARGET_ARM && NEED_PLT_RELOC)		\
102	       ? "(PLT)" : "");				\
103}
104
105/* VERY BIG NOTE: Change of structure alignment for NetBSD/arm.
106   There are consequences you should be aware of...
107
108   Normally GCC/arm uses a structure alignment of 32 for compatibility
109   with armcc.  This means that structures are padded to a word
110   boundary.  However this causes problems with bugged NetBSD kernel
111   code (possibly userland code as well - I have not checked every
112   binary).  The nature of this bugged code is to rely on sizeof()
113   returning the correct size of various structures rounded to the
114   nearest byte (SCSI and ether code are two examples, the vm system
115   is another).  This code breaks when the structure alignment is 32
116   as sizeof() will report a word=rounded size.  By changing the
117   structure alignment to 8. GCC will conform to what is expected by
118   NetBSD.
119
120   This has several side effects that should be considered.
121   1. Structures will only be aligned to the size of the largest member.
122      i.e. structures containing only bytes will be byte aligned.
123           structures containing shorts will be half word aligned.
124           structures containing ints will be word aligned.
125
126      This means structures should be padded to a word boundary if
127      alignment of 32 is required for byte structures etc.
128
129   2. A potential performance penalty may exist if strings are no longer
130      word aligned.  GCC will not be able to use word load/stores to copy
131      short strings.
132
133   This modification is not encouraged but with the present state of the
134   NetBSD source tree it is currently the only solution that meets the
135   requirements.  */
136
137#undef DEFAULT_STRUCTURE_SIZE_BOUNDARY
138#define DEFAULT_STRUCTURE_SIZE_BOUNDARY 8
139
140/* Clear the instruction cache from `BEG' to `END'.  This makes a
141   call to the ARM_SYNC_ICACHE architecture specific syscall.  */
142#define CLEAR_INSN_CACHE(BEG, END)					\
143do									\
144  {									\
145    extern int sysarch(int number, void *args);				\
146    struct								\
147      {									\
148	unsigned int addr;						\
149	int          len;						\
150      } s;								\
151    s.addr = (unsigned int)(BEG);					\
152    s.len = (END) - (BEG);						\
153    (void) sysarch (0, &s);						\
154  }									\
155while (0)
156
157#undef FPUTYPE_DEFAULT
158#define FPUTYPE_DEFAULT "vfp"
159
160