gcc/config/arm/netbsd.h

   1 /* NetBSD/arm a.out version.
   2    Copyright (C) 1993, 1994, 1997, 1998, 2003, 2004
   3    Free Software Foundation, Inc.
   4    Contributed by Mark Brinicombe (amb@physig.ph.kcl.ac.uk)
   5
   6    This file is part of GCC.
   7
   8    GCC is free software; you can redistribute it and/or modify it
   9    under the terms of the GNU General Public License as published
  10    by the Free Software Foundation; either version 2, or (at your
  11    option) any later version.
  12
  13    GCC is distributed in the hope that it will be useful, but WITHOUT
  14    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  16    License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with GCC; see the file COPYING.  If not, write to
  20    the Free Software Foundation, 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 /* Run-time Target Specification.  */
  24 #undef  TARGET_VERSION
  25 #define TARGET_VERSION fputs (" (ARM/NetBSD)", stderr);
  26
  27 /* Unsigned chars produces much better code than signed.  */
  28 #define DEFAULT_SIGNED_CHAR  0
  29
  30 /* Since we always use GAS as our assembler we support stabs.  */
  31 #define DBX_DEBUGGING_INFO 1
  32
  33 /*#undef ASM_DECLARE_FUNCTION_NAME*/
  34
  35 /* ARM6 family default cpu.  */
  36 #define SUBTARGET_CPU_DEFAULT TARGET_CPU_arm6
  37
  38 #undef TARGET_DEFAULT
  39 #define TARGET_DEFAULT (ARM_FLAG_APCS_FRAME)
  40
  41 /* Some defines for CPP.
  42    arm32 is the NetBSD port name, so we always define arm32 and __arm32__.  */
  43 #define TARGET_OS_CPP_BUILTINS()                \
  44     do {                                        \
  45         NETBSD_OS_CPP_BUILTINS_AOUT();          \
  46         builtin_define_std ("arm32");           \
  47         builtin_define_std ("unix");            \
  48         builtin_define_std ("riscbsd");         \
  49     } while (0)
  50
  51 #undef SUBTARGET_EXTRA_SPECS
  52 #define SUBTARGET_EXTRA_SPECS \
  53   { "netbsd_cpp_spec",  NETBSD_CPP_SPEC }, \
  54   { "netbsd_link_spec", NETBSD_LINK_SPEC_AOUT },
  55
  56 #undef CPP_SPEC
  57 #define CPP_SPEC "\
  58 %(cpp_cpu_arch) %(cpp_float) %(cpp_endian) %(netbsd_cpp_spec) \
  59 "
  60
  61 /* Because TARGET_DEFAULT sets ARM_FLAG_SOFT_FLOAT */
  62 #undef CPP_FLOAT_DEFAULT_SPEC
  63 #define CPP_FLOAT_DEFAULT_SPEC "-D__SOFTFP__"
  64
  65 /* Pass -X to the linker so that it will strip symbols starting with 'L' */
  66 #undef LINK_SPEC
  67 #define LINK_SPEC "-X %(netbsd_link_spec)"
  68
  69 #undef SIZE_TYPE
  70 #define SIZE_TYPE "unsigned int"
  71
  72 #undef PTRDIFF_TYPE
  73 #define PTRDIFF_TYPE "int"
  74
  75 #define HANDLE_SYSV_PRAGMA 1
  76
  77 /* We don't have any limit on the length as out debugger is GDB.  */
  78 #undef DBX_CONTIN_LENGTH
  79
  80 /* NetBSD does its profiling differently to the Acorn compiler. We
  81    don't need a word following the mcount call; and to skip it
  82    requires either an assembly stub or use of fomit-frame-pointer when
  83    compiling the profiling functions.  Since we break Acorn CC
  84    compatibility below a little more won't hurt.  */
  85
  86 #undef  ARM_FUNCTION_PROFILER
  87 #define ARM_FUNCTION_PROFILER(STREAM,LABELNO)                               \
  88 {                                                                           \
  89   fprintf(STREAM, "\tmov\t%sip, %slr\n", REGISTER_PREFIX, REGISTER_PREFIX); \
  90   fprintf(STREAM, "\tbl\tmcount\n");                                        \
  91 }
  92
  93 /* On the ARM `@' introduces a comment, so we must use something else
  94    for .type directives.  */
  95 #undef TYPE_OPERAND_FMT
  96 #define TYPE_OPERAND_FMT "%%%s"
  97
  98 /* NetBSD uses the old PCC style aggregate returning conventions.  */
  99 #undef DEFAULT_PCC_STRUCT_RETURN
 100 #define DEFAULT_PCC_STRUCT_RETURN 1
 101
 102 /* Although not normally relevant (since by default, all aggregates
 103    are returned in memory) compiling some parts of libc requires
 104    non-APCS style struct returns.  */
 105 #undef RETURN_IN_MEMORY
 106
 107 /* VERY BIG NOTE : Change of structure alignment for RiscBSD.
 108    There are consequences you should be aware of...
 109
 110    Normally GCC/arm uses a structure alignment of 32 for compatibility
 111    with armcc.  This means that structures are padded to a word
 112    boundary.  However this causes problems with bugged NetBSD kernel
 113    code (possibly userland code as well - I have not checked every
 114    binary).  The nature of this bugged code is to rely on sizeof()
 115    returning the correct size of various structures rounded to the
 116    nearest byte (SCSI and ether code are two examples, the vm system
 117    is another).  This code breaks when the structure alignment is 32
 118    as sizeof() will report a word=rounded size.  By changing the
 119    structure alignment to 8. GCC will conform to what is expected by
 120    NetBSD.
 121
 122    This has several side effects that should be considered.
 123    1. Structures will only be aligned to the size of the largest member.
 124       i.e. structures containing only bytes will be byte aligned.
 125            structures containing shorts will be half word aligned.
 126            structures containing ints will be word aligned.
 127
 128       This means structures should be padded to a word boundary if
 129       alignment of 32 is required for byte structures etc.
 130
 131    2. A potential performance penalty may exist if strings are no longer
 132       word aligned.  GCC will not be able to use word load/stores to copy
 133       short strings.
 134
 135    This modification is not encouraged but with the present state of the
 136    NetBSD source tree it is currently the only solution that meets the
 137    requirements.  */
 138 #undef  DEFAULT_STRUCTURE_SIZE_BOUNDARY
 139 #define DEFAULT_STRUCTURE_SIZE_BOUNDARY 8
 140
 141 /* Emit code to set up a trampoline and synchronize the caches.  */
 142 #undef  INITIALIZE_TRAMPOLINE
 143 #define INITIALIZE_TRAMPOLINE(TRAMP, FNADDR, CXT)                      \
 144 {                                                                      \
 145   emit_move_insn (gen_rtx_MEM (SImode, plus_constant ((TRAMP), 8)),   \
 146                  (CXT));                                               \
 147   emit_move_insn (gen_rtx_MEM (SImode, plus_constant ((TRAMP), 12)),  \
 148                  (FNADDR));                                            \
 149   emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__clear_cache"),      \
 150                     0, VOIDmode, 2, TRAMP, Pmode,                      \
 151                     plus_constant (TRAMP, TRAMPOLINE_SIZE), Pmode);    \
 152 }
 153
 154 /* Clear the instruction cache from `BEG' to `END'.  This makes a
 155    call to the ARM32_SYNC_ICACHE architecture specific syscall.  */
 156 #define CLEAR_INSN_CACHE(BEG, END)                                     \
 157 {                                                                      \
 158   extern int sysarch(int number, void *args);                          \
 159   struct {                                                             \
 160     unsigned int  addr;                                                \
 161     int           len;                                                 \
 162   } s;                                                                 \
 163   s.addr = (unsigned int)(BEG);                                        \
 164   s.len = (END) - (BEG);                                               \
 165   (void)sysarch(0, &s);                                                \
 166 }