sysdeps/i386/sysdep.h

   1 /* Assembler macros for i386.
   2    Copyright (C) 1991-93,95,96,98,2002,2003,2005 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <sysdeps/generic/sysdep.h>
  21
  22 #ifdef  __ASSEMBLER__
  23
  24 /* Syntactic details of assembler.  */
  25
  26 #ifdef HAVE_ELF
  27
  28 /* ELF uses byte-counts for .align, most others use log2 of count of bytes.  */
  29 #define ALIGNARG(log2) 1<<log2
  30 /* For ELF we need the `.type' directive to make shared libs work right.  */
  31 #define ASM_TYPE_DIRECTIVE(name,typearg) .type name,typearg;
  32 #define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
  33
  34 /* In ELF C symbols are asm symbols.  */
  35 #undef  NO_UNDERSCORES
  36 #define NO_UNDERSCORES
  37
  38 #else
  39
  40 #define ALIGNARG(log2) log2
  41 #define ASM_TYPE_DIRECTIVE(name,type)   /* Nothing is specified.  */
  42 #define ASM_SIZE_DIRECTIVE(name)        /* Nothing is specified.  */
  43
  44 #endif
  45
  46
  47 /* Define an entry point visible from C.
  48
  49    There is currently a bug in gdb which prevents us from specifying
  50    incomplete stabs information.  Fake some entries here which specify
  51    the current source file.  */
  52 #define ENTRY(name)                                                           \
  53   STABS_CURRENT_FILE1("")                                                     \
  54   STABS_CURRENT_FILE(name)                                                    \
  55   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name);                                   \
  56   ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),@function)                          \
  57   .align ALIGNARG(4);                                                         \
  58   STABS_FUN(name)                                                             \
  59   C_LABEL(name)                                                               \
  60   cfi_startproc;                                                              \
  61   CALL_MCOUNT
  62
  63 #undef  END
  64 #define END(name)                                                             \
  65   cfi_endproc;                                                                \
  66   ASM_SIZE_DIRECTIVE(name)                                                    \
  67   STABS_FUN_END(name)
  68
  69 #ifdef HAVE_CPP_ASM_DEBUGINFO
  70 /* Disable that goop, because we just pass -g through to the assembler
  71    and it generates proper line number information directly.  */
  72 # define STABS_CURRENT_FILE1(name)
  73 # define STABS_CURRENT_FILE(name)
  74 # define STABS_FUN(name)
  75 # define STABS_FUN_END(name)
  76 #else
  77 /* Remove the following two lines once the gdb bug is fixed.  */
  78 #define STABS_CURRENT_FILE(name)                                              \
  79   STABS_CURRENT_FILE1 (#name)
  80 #define STABS_CURRENT_FILE1(name)                                             \
  81   1: .stabs name,100,0,0,1b;
  82 /* Emit stabs definition lines.  We use F(0,1) and define t(0,1) as `int',
  83    the same way gcc does it.  */
  84 #define STABS_FUN(name) STABS_FUN2(name, name##:F(0,1))
  85 #define STABS_FUN2(name, namestr)                                             \
  86   .stabs "int:t(0,1)=r(0,1);-2147483648;2147483647;",128,0,0,0;               \
  87   .stabs #namestr,36,0,0,name;
  88 #define STABS_FUN_END(name)                                                   \
  89   1: .stabs "",36,0,0,1b-name;
  90 #endif
  91
  92 /* If compiled for profiling, call `mcount' at the start of each function.  */
  93 #ifdef  PROF
  94 /* The mcount code relies on a normal frame pointer being on the stack
  95    to locate our caller, so push one just for its benefit.  */
  96 #define CALL_MCOUNT \
  97   pushl %ebp; cfi_adjust_cfa_offset (4); movl %esp, %ebp; \
  98   cfi_def_cfa_register (ebp); call JUMPTARGET(mcount); \
  99   popl %ebp; cfi_def_cfa (esp, 4);
 100 #else
 101 #define CALL_MCOUNT             /* Do nothing.  */
 102 #endif
 103
 104 #ifdef  NO_UNDERSCORES
 105 /* Since C identifiers are not normally prefixed with an underscore
 106    on this system, the asm identifier `syscall_error' intrudes on the
 107    C name space.  Make sure we use an innocuous name.  */
 108 #define syscall_error   __syscall_error
 109 #define mcount          _mcount
 110 #endif
 111
 112 #define PSEUDO(name, syscall_name, args)                                      \
 113   .globl syscall_error;                                                       \
 114 lose: SYSCALL_PIC_SETUP                                                       \
 115   jmp JUMPTARGET(syscall_error);                                              \
 116   ENTRY (name)                                                                \
 117   DO_CALL (syscall_name, args);                                               \
 118   jb lose
 119
 120 #undef  PSEUDO_END
 121 #define PSEUDO_END(name)                                                      \
 122   END (name)
 123
 124 #undef JUMPTARGET
 125 #ifdef PIC
 126 #define JUMPTARGET(name)        name##@PLT
 127 #define SYSCALL_PIC_SETUP \
 128     pushl %ebx;                                                               \
 129     cfi_adjust_cfa_offset (4);                                                \
 130     call 0f;                                                                  \
 131 0:  popl %ebx;                                                                \
 132     cfi_adjust_cfa_offset (-4);                                               \
 133     addl $_GLOBAL_OFFSET_TABLE+[.-0b], %ebx;
 134
 135 # ifndef HAVE_HIDDEN
 136 #  define SETUP_PIC_REG(reg) \
 137   call 1f;                                                                    \
 138   .subsection 1;                                                              \
 139 1:movl (%esp), %e##reg;                                                       \
 140   ret;                                                                        \
 141   .previous
 142 # else
 143 #  define SETUP_PIC_REG(reg) \
 144   .ifndef __i686.get_pc_thunk.reg;                                            \
 145   .section .gnu.linkonce.t.__i686.get_pc_thunk.reg,"ax",@progbits;            \
 146   .globl __i686.get_pc_thunk.reg;                                             \
 147   .hidden __i686.get_pc_thunk.reg;                                            \
 148   .type __i686.get_pc_thunk.reg,@function;                                    \
 149 __i686.get_pc_thunk.reg:                                                      \
 150   movl (%esp), %e##reg;                                                       \
 151   ret;                                                                        \
 152   .size __i686.get_pc_thunk.reg, . - __i686.get_pc_thunk.reg;                 \
 153   .previous;                                                                  \
 154   .endif;                                                                     \
 155   call __i686.get_pc_thunk.reg
 156 # endif
 157
 158 # define LOAD_PIC_REG(reg) \
 159   SETUP_PIC_REG(reg); addl $_GLOBAL_OFFSET_TABLE_, %e##reg
 160
 161 #else
 162 #define JUMPTARGET(name)        name
 163 #define SYSCALL_PIC_SETUP       /* Nothing.  */
 164 #endif
 165
 166 /* Local label name for asm code. */
 167 #ifndef L
 168 #ifdef HAVE_ELF
 169 #define L(name)         .L##name
 170 #else
 171 #define L(name)         name
 172 #endif
 173 #endif
 174
 175 #endif  /* __ASSEMBLER__ */