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