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