1 /* Definitions of target machine for GNU compiler, NetBSD/arm ELF version.
2 Copyright (C) 2002-2013 Free Software Foundation, Inc.
3 Contributed by Wasabi Systems, Inc.
5 This file is part of GCC.
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.
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.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* Run-time Target Specification. */
23 /* arm.h defaults to ARM6 CPU. */
25 /* This defaults us to little-endian. */
26 #ifndef TARGET_ENDIAN_DEFAULT
27 #define TARGET_ENDIAN_DEFAULT 0
30 #undef MULTILIB_DEFAULTS
32 /* Default it to use ATPCS with soft-VFP. */
34 #define TARGET_DEFAULT \
36 | TARGET_ENDIAN_DEFAULT)
38 #undef ARM_DEFAULT_ABI
39 #define ARM_DEFAULT_ABI ARM_ABI_ATPCS
41 #define TARGET_OS_CPP_BUILTINS() \
44 NETBSD_OS_CPP_BUILTINS_ELF(); \
48 #undef SUBTARGET_CPP_SPEC
49 #define SUBTARGET_CPP_SPEC NETBSD_CPP_SPEC
51 #undef SUBTARGET_EXTRA_ASM_SPEC
52 #define SUBTARGET_EXTRA_ASM_SPEC \
53 "-matpcs %{fpic|fpie:-k} %{fPIC|fPIE:-k}"
55 /* Default to full VFP if -mfloat-abi=hard is specified. */
56 #undef SUBTARGET_ASM_FLOAT_SPEC
57 #define SUBTARGET_ASM_FLOAT_SPEC \
58 "%{mfloat-abi=hard:{!mfpu=*:-mfpu=vfp}}"
60 #undef SUBTARGET_EXTRA_SPECS
61 #define SUBTARGET_EXTRA_SPECS \
62 { "subtarget_extra_asm_spec", SUBTARGET_EXTRA_ASM_SPEC }, \
63 { "subtarget_asm_float_spec", SUBTARGET_ASM_FLOAT_SPEC }, \
64 { "netbsd_link_spec", NETBSD_LINK_SPEC_ELF }, \
65 { "netbsd_entry_point", NETBSD_ENTRY_POINT },
67 #define NETBSD_ENTRY_POINT "__start"
71 "-X %{mbig-endian:-EB} %{mlittle-endian:-EL} \
74 /* Make GCC agree with <machine/ansi.h>. */
77 #define SIZE_TYPE "long unsigned int"
80 #define PTRDIFF_TYPE "long int"
82 /* We don't have any limit on the length as out debugger is GDB. */
83 #undef DBX_CONTIN_LENGTH
85 /* NetBSD does its profiling differently to the Acorn compiler. We
86 don't need a word following the mcount call; and to skip it
87 requires either an assembly stub or use of fomit-frame-pointer when
88 compiling the profiling functions. Since we break Acorn CC
89 compatibility below a little more won't hurt. */
91 #undef ARM_FUNCTION_PROFILER
92 #define ARM_FUNCTION_PROFILER(STREAM,LABELNO) \
94 asm_fprintf (STREAM, "\tmov\t%Rip, %Rlr\n"); \
95 asm_fprintf (STREAM, "\tbl\t__mcount%s\n", \
96 (TARGET_ARM && NEED_PLT_RELOC) \
100 /* VERY BIG NOTE: Change of structure alignment for NetBSD/arm.
101 There are consequences you should be aware of...
103 Normally GCC/arm uses a structure alignment of 32 for compatibility
104 with armcc. This means that structures are padded to a word
105 boundary. However this causes problems with bugged NetBSD kernel
106 code (possibly userland code as well - I have not checked every
107 binary). The nature of this bugged code is to rely on sizeof()
108 returning the correct size of various structures rounded to the
109 nearest byte (SCSI and ether code are two examples, the vm system
110 is another). This code breaks when the structure alignment is 32
111 as sizeof() will report a word=rounded size. By changing the
112 structure alignment to 8. GCC will conform to what is expected by
115 This has several side effects that should be considered.
116 1. Structures will only be aligned to the size of the largest member.
117 i.e. structures containing only bytes will be byte aligned.
118 structures containing shorts will be half word aligned.
119 structures containing ints will be word aligned.
121 This means structures should be padded to a word boundary if
122 alignment of 32 is required for byte structures etc.
124 2. A potential performance penalty may exist if strings are no longer
125 word aligned. GCC will not be able to use word load/stores to copy
128 This modification is not encouraged but with the present state of the
129 NetBSD source tree it is currently the only solution that meets the
132 #undef DEFAULT_STRUCTURE_SIZE_BOUNDARY
133 #define DEFAULT_STRUCTURE_SIZE_BOUNDARY 8
135 /* Clear the instruction cache from `BEG' to `END'. This makes a
136 call to the ARM_SYNC_ICACHE architecture specific syscall. */
137 #define CLEAR_INSN_CACHE(BEG, END) \
140 extern int sysarch(int number, void *args); \
146 s.addr = (unsigned int)(BEG); \
147 s.len = (END) - (BEG); \
148 (void) sysarch (0, &s); \
152 #undef FPUTYPE_DEFAULT
153 #define FPUTYPE_DEFAULT "vfp"