gcc/config/arm/netbsd.h

   1 /*
   2    NetBSD/arm (RiscBSD) version.
   3    Copyright (C) 1993, 1994 Free Software Foundation, Inc.
   4    Contributed by Mark Brinicombe (amb@physig.ph.kcl.ac.uk)
   5
   6 This file is part of GNU CC.
   7
   8 GNU CC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2, or (at your option)
  11 any later version.
  12
  13 GNU CC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GNU CC; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  21
  22 /* Run-time Target Specification.  */
  23 #define TARGET_VERSION fputs (" (ARM/NetBSD)", stderr);
  24
  25 /* This is used in ASM_FILE_START.  */
  26 #define ARM_OS_NAME "NetBSD"
  27
  28 /* Unsigned chars produces much better code than signed.  */
  29 #define DEFAULT_SIGNED_CHAR  0
  30
  31 /* Since we always use GAS as our assembler we support stabs.  */
  32 #define DBX_DEBUGGING_INFO 1
  33
  34 /*#undef ASM_DECLARE_FUNCTION_NAME*/
  35
  36 /* ARM6 family default cpu.  */
  37 #define SUBTARGET_CPU_DEFAULT TARGET_CPU_arm6
  38
  39 /* Default is to use APCS-32 mode.  */
  40 #define TARGET_DEFAULT ARM_FLAG_APCS_32
  41
  42 #include "arm/aout.h"
  43
  44 /* This gets redefined in config/netbsd.h.  */
  45 #undef TARGET_MEM_FUNCTIONS
  46
  47 #include <netbsd.h>
  48
  49 /* Some defines for CPP.
  50    arm32 is the NetBSD port name, so we always define arm32 and __arm32__.  */
  51 #undef CPP_PREDEFINES
  52 #define CPP_PREDEFINES "\
  53 -Dunix -Driscbsd -Darm32 -D__arm32__ -D__NetBSD__ \
  54 -Asystem(unix) -Asystem(NetBSD) -Acpu(arm) -Amachine(arm)"
  55
  56 /* Define _POSIX_SOURCE if necessary.  */
  57 #undef CPP_SPEC
  58 #define CPP_SPEC "\
  59 %(cpp_cpu_arch) %(cpp_apcs_pc) %(cpp_float) %(cpp_endian) \
  60 %{posix:-D_POSIX_SOURCE} \
  61 "
  62
  63 /* Because TARGET_DEFAULT sets ARM_FLAG_APCS_32 */
  64 #undef CPP_APCS_PC_DEFAULT_SPEC
  65 #define CPP_APCS_PC_DEFAULT_SPEC "-D__APCS_32__"
  66
  67 #undef SIZE_TYPE
  68 #define SIZE_TYPE "unsigned int"
  69
  70 #undef PTRDIFF_TYPE
  71 #define PTRDIFF_TYPE "int"
  72
  73 #undef WCHAR_TYPE
  74 #define WCHAR_TYPE "int"
  75
  76 #undef WCHAR_UNSIGNED
  77 #define WCHAR_UNSIGNED 0
  78
  79 #undef WCHAR_TYPE_SIZE
  80 #define WCHAR_TYPE_SIZE 32
  81
  82 #define HANDLE_SYSV_PRAGMA
  83
  84 /* We don't have any limit on the length as out debugger is GDB.  */
  85 #undef DBX_CONTIN_LENGTH
  86
  87 /* NetBSD does its profiling differently to the Acorn compiler. We
  88    don't need a word following the mcount call; and to skip it
  89    requires either an assembly stub or use of fomit-frame-pointer when
  90    compiling the profiling functions.  Since we break Acorn CC
  91    compatibility below a little more won't hurt.  */
  92
  93 #undef FUNCTION_PROFILER
  94 #define FUNCTION_PROFILER(STREAM,LABELNO)                                   \
  95 {                                                                           \
  96   fprintf(STREAM, "\tmov\t%sip, %slr\n", REGISTER_PREFIX, REGISTER_PREFIX); \
  97   fprintf(STREAM, "\tbl\tmcount\n");                                        \
  98 }
  99
 100 /* VERY BIG NOTE : Change of structure alignment for RiscBSD.
 101    There are consequences you should be aware of...
 102
 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    boundry.  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
 113    NetBSD.
 114
 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 alinged.
 119            structures containing ints will be word aligned.
 120
 121       This means structures should be padded to a word boundry if
 122       alignment of 32 is required for byte structures etc.
 123
 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
 126       short strings.
 127
 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
 130    requirements.  */
 131 #undef STRUCTURE_SIZE_BOUNDARY
 132 #define STRUCTURE_SIZE_BOUNDARY 8