gcc/config/arm/netbsd.h

   1 /* NetBSD/arm a.out version.
   2    Copyright (C) 1993, 1994, 1997, 1998, 2003, 2004, 2005, 2007
   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 3, 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 COPYING3.  If not see
  20    <http://www.gnu.org/licenses/>.  */
  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 #undef TARGET_DEFAULT
  38 #define TARGET_DEFAULT (MASK_APCS_FRAME)
  39
  40 /* Some defines for CPP.
  41    arm32 is the NetBSD port name, so we always define arm32 and __arm32__.  */
  42 #define TARGET_OS_CPP_BUILTINS()                \
  43     do {                                        \
  44         NETBSD_OS_CPP_BUILTINS_AOUT();          \
  45         builtin_define_std ("arm32");           \
  46         builtin_define_std ("unix");            \
  47         builtin_define_std ("riscbsd");         \
  48     } while (0)
  49
  50 #undef SUBTARGET_EXTRA_SPECS
  51 #define SUBTARGET_EXTRA_SPECS \
  52   { "netbsd_cpp_spec",  NETBSD_CPP_SPEC }, \
  53   { "netbsd_link_spec", NETBSD_LINK_SPEC_AOUT },
  54
  55 #undef CPP_SPEC
  56 #define CPP_SPEC "\
  57 %(cpp_cpu_arch) %(cpp_float) %(cpp_endian) %(netbsd_cpp_spec) \
  58 "
  59
  60 /* Because TARGET_DEFAULT sets MASK_SOFT_FLOAT */
  61 #undef CPP_FLOAT_DEFAULT_SPEC
  62 #define CPP_FLOAT_DEFAULT_SPEC "-D__SOFTFP__"
  63
  64 /* Pass -X to the linker so that it will strip symbols starting with 'L' */
  65 #undef LINK_SPEC
  66 #define LINK_SPEC "-X %(netbsd_link_spec)"
  67
  68 #undef SIZE_TYPE
  69 #define SIZE_TYPE "unsigned int"
  70
  71 #undef PTRDIFF_TYPE
  72 #define PTRDIFF_TYPE "int"
  73
  74 #define HANDLE_SYSV_PRAGMA 1
  75
  76 /* We don't have any limit on the length as out debugger is GDB.  */
  77 #undef DBX_CONTIN_LENGTH
  78
  79 /* NetBSD does its profiling differently to the Acorn compiler. We
  80    don't need a word following the mcount call; and to skip it
  81    requires either an assembly stub or use of fomit-frame-pointer when
  82    compiling the profiling functions.  Since we break Acorn CC
  83    compatibility below a little more won't hurt.  */
  84
  85 #undef  ARM_FUNCTION_PROFILER
  86 #define ARM_FUNCTION_PROFILER(STREAM,LABELNO)                               \
  87 {                                                                           \
  88   fprintf(STREAM, "\tmov\t%sip, %slr\n", REGISTER_PREFIX, REGISTER_PREFIX); \
  89   fprintf(STREAM, "\tbl\tmcount\n");                                        \
  90 }
  91
  92 /* On the ARM `@' introduces a comment, so we must use something else
  93    for .type directives.  */
  94 #undef TYPE_OPERAND_FMT
  95 #define TYPE_OPERAND_FMT "%%%s"
  96
  97 /* NetBSD uses the old PCC style aggregate returning conventions.  */
  98 #undef DEFAULT_PCC_STRUCT_RETURN
  99 #define DEFAULT_PCC_STRUCT_RETURN 1
 100
 101 /* Although not normally relevant (since by default, all aggregates
 102    are returned in memory) compiling some parts of libc requires
 103    non-APCS style struct returns.  */
 104 #undef TARGET_RETURN_IN_MEMORY
 105
 106 /* VERY BIG NOTE : Change of structure alignment for RiscBSD.
 107    There are consequences you should be aware of...
 108
 109    Normally GCC/arm uses a structure alignment of 32 for compatibility
 110    with armcc.  This means that structures are padded to a word
 111    boundary.  However this causes problems with bugged NetBSD kernel
 112    code (possibly userland code as well - I have not checked every
 113    binary).  The nature of this bugged code is to rely on sizeof()
 114    returning the correct size of various structures rounded to the
 115    nearest byte (SCSI and ether code are two examples, the vm system
 116    is another).  This code breaks when the structure alignment is 32
 117    as sizeof() will report a word=rounded size.  By changing the
 118    structure alignment to 8. GCC will conform to what is expected by
 119    NetBSD.
 120
 121    This has several side effects that should be considered.
 122    1. Structures will only be aligned to the size of the largest member.
 123       i.e. structures containing only bytes will be byte aligned.
 124            structures containing shorts will be half word aligned.
 125            structures containing ints will be word aligned.
 126
 127       This means structures should be padded to a word boundary if
 128       alignment of 32 is required for byte structures etc.
 129
 130    2. A potential performance penalty may exist if strings are no longer
 131       word aligned.  GCC will not be able to use word load/stores to copy
 132       short strings.
 133
 134    This modification is not encouraged but with the present state of the
 135    NetBSD source tree it is currently the only solution that meets the
 136    requirements.  */
 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 ARM32_SYNC_ICACHE architecture specific syscall.  */
 142 #define CLEAR_INSN_CACHE(BEG, END)                                     \
 143 {                                                                      \
 144   extern int sysarch(int number, void *args);                          \
 145   struct {                                                             \
 146     unsigned int  addr;                                                \
 147     int           len;                                                 \
 148   } s;                                                                 \
 149   s.addr = (unsigned int)(BEG);                                        \
 150   s.len = (END) - (BEG);                                               \
 151   (void)sysarch(0, &s);                                                \
 152 }