gcc/config/m68k/linux.h

   1 /* Definitions for Motorola 68k running Linux-based GNU systems with
   2    ELF format.
   3    Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2006
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC 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 GCC 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 GCC; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  21 Boston, MA 02110-1301, USA.  */
  22
  23 #undef TARGET_VERSION
  24 #define TARGET_VERSION fprintf (stderr, " (68k GNU/Linux with ELF)");
  25
  26 /* Default target comes from config.gcc.  */
  27
  28 #undef TARGET_DEFAULT
  29 #ifdef TARGET_CPU_DEFAULT
  30 #define TARGET_DEFAULT TARGET_CPU_DEFAULT
  31 #else
  32 #define TARGET_DEFAULT (MASK_BITFIELD|MASK_68881|MASK_68020)
  33 #endif
  34
  35 /* for 68k machines this only needs to be TRUE for the 68000 */
  36
  37 #undef STRICT_ALIGNMENT
  38 #define STRICT_ALIGNMENT 0
  39
  40 /* Here are four prefixes that are used by asm_fprintf to
  41    facilitate customization for alternate assembler syntaxes.
  42    Machines with no likelihood of an alternate syntax need not
  43    define these and need not use asm_fprintf.  */
  44
  45 /* The prefix for register names.  Note that REGISTER_NAMES
  46    is supposed to include this prefix. Also note that this is NOT an
  47    fprintf format string, it is a literal string */
  48
  49 #undef REGISTER_PREFIX
  50 #define REGISTER_PREFIX "%"
  51
  52 /* The prefix for local (compiler generated) labels.
  53    These labels will not appear in the symbol table.  */
  54
  55 #undef LOCAL_LABEL_PREFIX
  56 #define LOCAL_LABEL_PREFIX "."
  57
  58 /* The prefix to add to user-visible assembler symbols.  */
  59
  60 #undef USER_LABEL_PREFIX
  61 #define USER_LABEL_PREFIX ""
  62
  63 #define ASM_COMMENT_START "|"
  64
  65 #undef SIZE_TYPE
  66 #define SIZE_TYPE "unsigned int"
  67
  68 #undef PTRDIFF_TYPE
  69 #define PTRDIFF_TYPE "int"
  70
  71 #undef WCHAR_TYPE
  72 #define WCHAR_TYPE "long int"
  73
  74 #undef WCHAR_TYPE_SIZE
  75 #define WCHAR_TYPE_SIZE BITS_PER_WORD
  76
  77 /* Target OS builtins.  */
  78 #define TARGET_OS_CPP_BUILTINS()                \
  79   do                                            \
  80     {                                           \
  81         LINUX_TARGET_OS_CPP_BUILTINS();         \
  82         builtin_define_std ("mc68000");         \
  83         builtin_define_std ("mc68020");         \
  84    }                                            \
  85   while (0)
  86
  87 #define TARGET_OBJFMT_CPP_BUILTINS()            \
  88   do                                            \
  89     {                                           \
  90         builtin_define ("__ELF__");             \
  91     }                                           \
  92   while (0)
  93
  94 #undef CPP_SPEC
  95 #if TARGET_DEFAULT & MASK_68881
  96 #define CPP_SPEC \
  97   "%{!msoft-float:-D__HAVE_68881__} %{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"
  98 #else
  99 #define CPP_SPEC \
 100   "%{m68881:-D__HAVE_68881__} %{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"
 101 #endif
 102
 103 /* We override the ASM_SPEC from svr4.h because we must pass -m68040 down
 104    to the assembler.  */
 105 #undef ASM_SPEC
 106 #define ASM_SPEC \
 107   "%{v:-V} %{Qy:} %{!Qn:-Qy} %{n} %{T} %{Ym,*} %{Yd,*} %{Wa,*:%*} \
 108 %{m68040} %{m68060:-m68040}"
 109
 110 /* Provide a LINK_SPEC appropriate for GNU/Linux.  Here we provide support
 111    for the special GCC options -static and -shared, which allow us to
 112    link things in one of these three modes by applying the appropriate
 113    combinations of options at link-time.  We like to support here for
 114    as many of the other GNU linker options as possible.  But I don't
 115    have the time to search for those flags.  I am sure how to add
 116    support for -soname shared_object_name. H.J.
 117
 118    I took out %{v:%{!V:-V}}.  It is too much :-(.  They can use
 119    -Wl,-V.
 120
 121    When the -shared link option is used a final link is not being
 122    done.  */
 123
 124 /* If ELF is the default format, we should not use /lib/elf.  */
 125
 126 #undef  LINK_SPEC
 127 #define LINK_SPEC "-m m68kelf %{shared} \
 128   %{!shared: \
 129     %{!static: \
 130       %{rdynamic:-export-dynamic} \
 131       %{!dynamic-linker*:-dynamic-linker /lib/ld.so.1}} \
 132     %{static}}"
 133
 134 /* For compatibility with linux/a.out */
 135
 136 #undef PCC_BITFIELD_TYPE_MATTERS
 137
 138 /* Currently, JUMP_TABLES_IN_TEXT_SECTION must be defined in order to
 139    keep switch tables in the text section.  */
 140
 141 #define JUMP_TABLES_IN_TEXT_SECTION 1
 142
 143 /* Use the default action for outputting the case label.  */
 144 #undef ASM_OUTPUT_CASE_LABEL
 145 #define ASM_RETURN_CASE_JUMP                            \
 146   do {                                                  \
 147     if (TARGET_COLDFIRE)                                \
 148       {                                                 \
 149         if (ADDRESS_REG_P (operands[0]))                \
 150           return "jmp %%pc@(2,%0:l)";                   \
 151         else                                            \
 152           return "ext%.l %0\n\tjmp %%pc@(2,%0:l)";      \
 153       }                                                 \
 154     else                                                \
 155       return "jmp %%pc@(2,%0:w)";                       \
 156   } while (0)
 157
 158 /* This is how to output an assembler line that says to advance the
 159    location counter to a multiple of 2**LOG bytes.  */
 160
 161 #undef ASM_OUTPUT_ALIGN
 162 #define ASM_OUTPUT_ALIGN(FILE,LOG)                              \
 163   if ((LOG) > 0)                                                \
 164     fprintf ((FILE), "%s%u\n", ALIGN_ASM_OP, 1 << (LOG));
 165
 166 /* If defined, a C expression whose value is a string containing the
 167    assembler operation to identify the following data as uninitialized global
 168    data.  */
 169
 170 #define BSS_SECTION_ASM_OP "\t.section\t.bss"
 171
 172 /* A C statement (sans semicolon) to output to the stdio stream
 173    FILE the assembler definition of uninitialized global DECL named
 174    NAME whose size is SIZE bytes and alignment is ALIGN bytes.
 175    Try to use asm_output_aligned_bss to implement this macro.  */
 176
 177 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 178   asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
 179
 180 /* Output assembler code to FILE to increment profiler label # LABELNO
 181    for profiling a function entry.  */
 182
 183 #undef FUNCTION_PROFILER
 184 #define FUNCTION_PROFILER(FILE, LABELNO) \
 185 {                                                                       \
 186   asm_fprintf (FILE, "\tlea (%LLP%d,%Rpc),%Ra1\n", (LABELNO));          \
 187   if (flag_pic)                                                         \
 188     fprintf (FILE, "\tbsr.l _mcount@PLTPC\n");                          \
 189   else                                                                  \
 190     fprintf (FILE, "\tjbsr _mcount\n");                                 \
 191 }
 192
 193 /* How to renumber registers for dbx and gdb.
 194    On the Sun-3, the floating point registers have numbers
 195    18 to 25, not 16 to 23 as they do in the compiler.  */
 196
 197 #define DBX_REGISTER_NUMBER(REGNO) ((REGNO) < 16 ? (REGNO) : (REGNO) + 2)
 198
 199 /* Do not break .stabs pseudos into continuations.  */
 200
 201 #define DBX_CONTIN_LENGTH 0
 202
 203 /* 1 if N is a possible register number for a function value.  For
 204    m68k/SVR4 allow d0, a0, or fp0 as return registers, for integral,
 205    pointer, or floating types, respectively.  Reject fp0 if not using
 206    a 68881 coprocessor.  */
 207
 208 #undef FUNCTION_VALUE_REGNO_P
 209 #define FUNCTION_VALUE_REGNO_P(N) \
 210   ((N) == 0 || (N) == 8 || (TARGET_68881 && (N) == 16))
 211
 212 /* Define this to be true when FUNCTION_VALUE_REGNO_P is true for
 213    more than one register.  */
 214
 215 #undef NEEDS_UNTYPED_CALL
 216 #define NEEDS_UNTYPED_CALL 1
 217
 218 /* Define how to generate (in the callee) the output value of a
 219    function and how to find (in the caller) the value returned by a
 220    function.  VALTYPE is the data type of the value (as a tree).  If
 221    the precise function being called is known, FUNC is its
 222    FUNCTION_DECL; otherwise, FUNC is 0.  For m68k/SVR4 generate the
 223    result in d0, a0, or fp0 as appropriate.  */
 224
 225 #undef FUNCTION_VALUE
 226 #define FUNCTION_VALUE(VALTYPE, FUNC)                                   \
 227   m68k_function_value (VALTYPE, FUNC)
 228
 229 /* For compatibility with the large body of existing code which does
 230    not always properly declare external functions returning pointer
 231    types, the m68k/SVR4 convention is to copy the value returned for
 232    pointer functions from a0 to d0 in the function epilogue, so that
 233    callers that have neglected to properly declare the callee can
 234    still find the correct return value.  */
 235
 236 #define FUNCTION_EXTRA_EPILOGUE(FILE, SIZE)                             \
 237 do {                                                                    \
 238   if (current_function_returns_pointer                                  \
 239       && ! find_equiv_reg (0, get_last_insn (), 0, 0, 0, 8, Pmode))     \
 240     asm_fprintf (FILE, "\tmove.l %Ra0,%Rd0\n");                         \
 241 } while (0);
 242
 243 /* Define how to find the value returned by a library function
 244    assuming the value has mode MODE.
 245    For m68k/SVR4 look for integer values in d0, pointer values in d0
 246    (returned in both d0 and a0), and floating values in fp0.  */
 247
 248 #undef LIBCALL_VALUE
 249 #define LIBCALL_VALUE(MODE)                                             \
 250   m68k_libcall_value (MODE)
 251
 252 /* For m68k SVR4, structures are returned using the reentrant
 253    technique.  */
 254 #undef PCC_STATIC_STRUCT_RETURN
 255 #define DEFAULT_PCC_STRUCT_RETURN 0
 256
 257 /* Finalize the trampoline by flushing the insn cache.  */
 258
 259 #undef FINALIZE_TRAMPOLINE
 260 #define FINALIZE_TRAMPOLINE(TRAMP)                                      \
 261   emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__clear_cache"),       \
 262                      0, VOIDmode, 2, TRAMP, Pmode,                      \
 263                      plus_constant (TRAMP, TRAMPOLINE_SIZE), Pmode);
 264
 265 /* Clear the instruction cache from `beg' to `end'.  This makes an
 266    inline system call to SYS_cacheflush.  The arguments are as
 267    follows:
 268
 269         cacheflush (addr, scope, cache, len)
 270
 271    addr   - the start address for the flush
 272    scope  - the scope of the flush (see the cpush insn)
 273    cache  - which cache to flush (see the cpush insn)
 274    len    - a factor relating to the number of flushes to perform:
 275             len/16 lines, or len/4096 pages.  */
 276
 277 #define CLEAR_INSN_CACHE(BEG, END)                                      \
 278 {                                                                       \
 279   register unsigned long _beg __asm ("%d1") = (unsigned long) (BEG);    \
 280   unsigned long _end = (unsigned long) (END);                           \
 281   register unsigned long _len __asm ("%d4") = (_end - _beg + 32);       \
 282   __asm __volatile                                                      \
 283     ("move%.l #123, %/d0\n\t"   /* system call nr */                    \
 284      "move%.l #1, %/d2\n\t"     /* clear lines */                       \
 285      "move%.l #3, %/d3\n\t"     /* insn+data caches */                  \
 286      "trap #0"                                                          \
 287      : /* no outputs */                                                 \
 288      : "d" (_beg), "d" (_len)                                           \
 289      : "%d0", "%d2", "%d3");                                            \
 290 }
 291
 292 #define TARGET_ASM_FILE_END file_end_indicate_exec_stack