gcc/config/arm/netbsd.h

   1 /* NetBSD/arm a.out version.
   2    Copyright (C) 1993, 1994, 1997, 1998, 2003 Free Software Foundation, Inc.
   3    Contributed by Mark Brinicombe (amb@physig.ph.kcl.ac.uk)
   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 2, 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    You should have received a copy of the GNU General Public License
  18    along with GCC; see the file COPYING.  If not, write to
  19    the Free Software Foundation, 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 /* Run-time Target Specification.  */
  23 #undef  TARGET_VERSION
  24 #define TARGET_VERSION fputs (" (ARM/NetBSD)", stderr);
  25
  26 /* This is used in ASM_FILE_START.  */
  27 #undef ARM_OS_NAME
  28 #define ARM_OS_NAME "NetBSD"
  29
  30 /* Unsigned chars produces much better code than signed.  */
  31 #define DEFAULT_SIGNED_CHAR  0
  32
  33 /* Since we always use GAS as our assembler we support stabs.  */
  34 #define DBX_DEBUGGING_INFO 1
  35
  36 /*#undef ASM_DECLARE_FUNCTION_NAME*/
  37
  38 /* ARM6 family default cpu.  */
  39 #define SUBTARGET_CPU_DEFAULT TARGET_CPU_arm6
  40
  41 /* Default is to use APCS-32 mode.  */
  42 #undef TARGET_DEFAULT
  43 #define TARGET_DEFAULT (ARM_FLAG_APCS_32 | ARM_FLAG_SOFT_FLOAT | ARM_FLAG_APCS_FRAME)
  44
  45 /* Some defines for CPP.
  46    arm32 is the NetBSD port name, so we always define arm32 and __arm32__.  */
  47 #define TARGET_OS_CPP_BUILTINS()                \
  48     do {                                        \
  49         NETBSD_OS_CPP_BUILTINS_AOUT();          \
  50         builtin_define_std ("arm32");           \
  51         builtin_define_std ("unix");            \
  52         builtin_define_std ("riscbsd");         \
  53     } while (0)
  54
  55 #undef SUBTARGET_EXTRA_SPECS
  56 #define SUBTARGET_EXTRA_SPECS \
  57   { "netbsd_cpp_spec",  NETBSD_CPP_SPEC }, \
  58   { "netbsd_link_spec", NETBSD_LINK_SPEC_AOUT },
  59
  60 #undef CPP_SPEC
  61 #define CPP_SPEC "\
  62 %(cpp_cpu_arch) %(cpp_apcs_pc) %(cpp_float) %(cpp_endian) %(netbsd_cpp_spec) \
  63 "
  64
  65 /* Because TARGET_DEFAULT sets ARM_FLAG_APCS_32 */
  66 #undef CPP_APCS_PC_DEFAULT_SPEC
  67 #define CPP_APCS_PC_DEFAULT_SPEC "-D__APCS_32__"
  68
  69 /* Because TARGET_DEFAULT sets ARM_FLAG_SOFT_FLOAT */
  70 #undef CPP_FLOAT_DEFAULT_SPEC
  71 #define CPP_FLOAT_DEFAULT_SPEC "-D__SOFTFP__"
  72
  73 /* Pass -X to the linker so that it will strip symbols starting with 'L' */
  74 #undef LINK_SPEC
  75 #define LINK_SPEC "-X %(netbsd_link_spec)"
  76
  77 #undef SIZE_TYPE
  78 #define SIZE_TYPE "unsigned int"
  79
  80 #undef PTRDIFF_TYPE
  81 #define PTRDIFF_TYPE "int"
  82
  83 #define HANDLE_SYSV_PRAGMA 1
  84
  85 /* We don't have any limit on the length as out debugger is GDB.  */
  86 #undef DBX_CONTIN_LENGTH
  87
  88 /* NetBSD does its profiling differently to the Acorn compiler. We
  89    don't need a word following the mcount call; and to skip it
  90    requires either an assembly stub or use of fomit-frame-pointer when
  91    compiling the profiling functions.  Since we break Acorn CC
  92    compatibility below a little more won't hurt.  */
  93
  94 #undef  ARM_FUNCTION_PROFILER
  95 #define ARM_FUNCTION_PROFILER(STREAM,LABELNO)                               \
  96 {                                                                           \
  97   fprintf(STREAM, "\tmov\t%sip, %slr\n", REGISTER_PREFIX, REGISTER_PREFIX); \
  98   fprintf(STREAM, "\tbl\tmcount\n");                                        \
  99 }
 100
 101 /* On the ARM `@' introduces a comment, so we must use something else
 102    for .type directives.  */
 103 #undef TYPE_OPERAND_FMT
 104 #define TYPE_OPERAND_FMT "%%%s"
 105
 106 /* NetBSD uses the old PCC style aggregate returning conventions.  */
 107 #undef DEFAULT_PCC_STRUCT_RETURN
 108 #define DEFAULT_PCC_STRUCT_RETURN 1
 109
 110 /* Although not normally relevant (since by default, all aggregates
 111    are returned in memory) compiling some parts of libc requires
 112    non-APCS style struct returns.  */
 113 #undef RETURN_IN_MEMORY
 114
 115 /* VERY BIG NOTE : Change of structure alignment for RiscBSD.
 116    There are consequences you should be aware of...
 117
 118    Normally GCC/arm uses a structure alignment of 32 for compatibility
 119    with armcc.  This means that structures are padded to a word
 120    boundary.  However this causes problems with bugged NetBSD kernel
 121    code (possibly userland code as well - I have not checked every
 122    binary).  The nature of this bugged code is to rely on sizeof()
 123    returning the correct size of various structures rounded to the
 124    nearest byte (SCSI and ether code are two examples, the vm system
 125    is another).  This code breaks when the structure alignment is 32
 126    as sizeof() will report a word=rounded size.  By changing the
 127    structure alignment to 8. GCC will conform to what is expected by
 128    NetBSD.
 129
 130    This has several side effects that should be considered.
 131    1. Structures will only be aligned to the size of the largest member.
 132       i.e. structures containing only bytes will be byte aligned.
 133            structures containing shorts will be half word aligned.
 134            structures containing ints will be word aligned.
 135
 136       This means structures should be padded to a word boundary if
 137       alignment of 32 is required for byte structures etc.
 138
 139    2. A potential performance penalty may exist if strings are no longer
 140       word aligned.  GCC will not be able to use word load/stores to copy
 141       short strings.
 142
 143    This modification is not encouraged but with the present state of the
 144    NetBSD source tree it is currently the only solution that meets the
 145    requirements.  */
 146 #undef  DEFAULT_STRUCTURE_SIZE_BOUNDARY
 147 #define DEFAULT_STRUCTURE_SIZE_BOUNDARY 8
 148
 149 /* Emit code to set up a trampoline and synchronize the caches.  */
 150 #undef  INITIALIZE_TRAMPOLINE
 151 #define INITIALIZE_TRAMPOLINE(TRAMP, FNADDR, CXT)                      \
 152 {                                                                      \
 153   emit_move_insn (gen_rtx (MEM, SImode, plus_constant ((TRAMP), 8)),   \
 154                  (CXT));                                               \
 155   emit_move_insn (gen_rtx (MEM, SImode, plus_constant ((TRAMP), 12)),  \
 156                  (FNADDR));                                            \
 157   emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__clear_cache"),      \
 158                     0, VOIDmode, 2, TRAMP, Pmode,                      \
 159                     plus_constant (TRAMP, TRAMPOLINE_SIZE), Pmode);    \
 160 }
 161
 162 /* Clear the instruction cache from `BEG' to `END'.  This makes a
 163    call to the ARM32_SYNC_ICACHE architecture specific syscall.  */
 164 #define CLEAR_INSN_CACHE(BEG, END)                                     \
 165 {                                                                      \
 166   extern int sysarch(int number, void *args);                          \
 167   struct {                                                             \
 168     unsigned int  addr;                                                \
 169     int           len;                                                 \
 170   } s;                                                                 \
 171   s.addr = (unsigned int)(BEG);                                        \
 172   s.len = (END) - (BEG);                                               \
 173   (void)sysarch(0, &s);                                                \
 174 }