sysdeps/i386/sysdep.h

   1 /* Assembler macros for i386.
   2    Copyright (C) 1991-93,95,96,98,2002,2003,2005,2006
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <sysdeps/generic/sysdep.h>
  22
  23 #ifdef  __ASSEMBLER__
  24
  25 /* Syntactic details of assembler.  */
  26
  27 #ifdef HAVE_ELF
  28
  29 /* ELF uses byte-counts for .align, most others use log2 of count of bytes.  */
  30 #define ALIGNARG(log2) 1<<log2
  31 /* For ELF we need the `.type' directive to make shared libs work right.  */
  32 #define ASM_TYPE_DIRECTIVE(name,typearg) .type name,typearg;
  33 #define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
  34
  35 /* In ELF C symbols are asm symbols.  */
  36 #undef  NO_UNDERSCORES
  37 #define NO_UNDERSCORES
  38
  39 #else
  40
  41 #define ALIGNARG(log2) log2
  42 #define ASM_TYPE_DIRECTIVE(name,type)   /* Nothing is specified.  */
  43 #define ASM_SIZE_DIRECTIVE(name)        /* Nothing is specified.  */
  44
  45 #endif
  46
  47
  48 /* Define an entry point visible from C.
  49
  50    There is currently a bug in gdb which prevents us from specifying
  51    incomplete stabs information.  Fake some entries here which specify
  52    the current source file.  */
  53 #define ENTRY(name)                                                           \
  54   STABS_CURRENT_FILE1("")                                                     \
  55   STABS_CURRENT_FILE(name)                                                    \
  56   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name);                                   \
  57   ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),@function)                          \
  58   .align ALIGNARG(4);                                                         \
  59   STABS_FUN(name)                                                             \
  60   C_LABEL(name)                                                               \
  61   cfi_startproc;                                                              \
  62   CALL_MCOUNT
  63
  64 #undef  END
  65 #define END(name)                                                             \
  66   cfi_endproc;                                                                \
  67   ASM_SIZE_DIRECTIVE(name)                                                    \
  68   STABS_FUN_END(name)
  69
  70 #ifdef HAVE_CPP_ASM_DEBUGINFO
  71 /* Disable that goop, because we just pass -g through to the assembler
  72    and it generates proper line number information directly.  */
  73 # define STABS_CURRENT_FILE1(name)
  74 # define STABS_CURRENT_FILE(name)
  75 # define STABS_FUN(name)
  76 # define STABS_FUN_END(name)
  77 #else
  78 /* Remove the following two lines once the gdb bug is fixed.  */
  79 #define STABS_CURRENT_FILE(name)                                              \
  80   STABS_CURRENT_FILE1 (#name)
  81 #define STABS_CURRENT_FILE1(name)                                             \
  82   1: .stabs name,100,0,0,1b;
  83 /* Emit stabs definition lines.  We use F(0,1) and define t(0,1) as `int',
  84    the same way gcc does it.  */
  85 #define STABS_FUN(name) STABS_FUN2(name, name##:F(0,1))
  86 #define STABS_FUN2(name, namestr)                                             \
  87   .stabs "int:t(0,1)=r(0,1);-2147483648;2147483647;",128,0,0,0;               \
  88   .stabs #namestr,36,0,0,name;
  89 #define STABS_FUN_END(name)                                                   \
  90   1: .stabs "",36,0,0,1b-name;
  91 #endif
  92
  93 /* If compiled for profiling, call `mcount' at the start of each function.  */
  94 #ifdef  PROF
  95 /* The mcount code relies on a normal frame pointer being on the stack
  96    to locate our caller, so push one just for its benefit.  */
  97 #define CALL_MCOUNT \
  98   pushl %ebp; cfi_adjust_cfa_offset (4); movl %esp, %ebp; \
  99   cfi_def_cfa_register (ebp); call JUMPTARGET(mcount); \
 100   popl %ebp; cfi_def_cfa (esp, 4);
 101 #else
 102 #define CALL_MCOUNT             /* Do nothing.  */
 103 #endif
 104
 105 #ifdef  NO_UNDERSCORES
 106 /* Since C identifiers are not normally prefixed with an underscore
 107    on this system, the asm identifier `syscall_error' intrudes on the
 108    C name space.  Make sure we use an innocuous name.  */
 109 #define syscall_error   __syscall_error
 110 #define mcount          _mcount
 111 #endif
 112
 113 #define PSEUDO(name, syscall_name, args)                                      \
 114   .globl syscall_error;                                                       \
 115 lose: SYSCALL_PIC_SETUP                                                       \
 116   jmp JUMPTARGET(syscall_error);                                              \
 117   ENTRY (name)                                                                \
 118   DO_CALL (syscall_name, args);                                               \
 119   jb lose
 120
 121 #undef  PSEUDO_END
 122 #define PSEUDO_END(name)                                                      \
 123   END (name)
 124
 125 #undef JUMPTARGET
 126 #ifdef PIC
 127 #define JUMPTARGET(name)        name##@PLT
 128 #define SYSCALL_PIC_SETUP \
 129     pushl %ebx;                                                               \
 130     cfi_adjust_cfa_offset (4);                                                \
 131     call 0f;                                                                  \
 132 0:  popl %ebx;                                                                \
 133     cfi_adjust_cfa_offset (-4);                                               \
 134     addl $_GLOBAL_OFFSET_TABLE+[.-0b], %ebx;
 135
 136 # define SETUP_PIC_REG(reg) \
 137   .ifndef __i686.get_pc_thunk.reg;                                            \
 138   .section .gnu.linkonce.t.__i686.get_pc_thunk.reg,"ax",@progbits;            \
 139   .globl __i686.get_pc_thunk.reg;                                             \
 140   .hidden __i686.get_pc_thunk.reg;                                            \
 141   .type __i686.get_pc_thunk.reg,@function;                                    \
 142 __i686.get_pc_thunk.reg:                                                      \
 143   movl (%esp), %e##reg;                                                       \
 144   ret;                                                                        \
 145   .size __i686.get_pc_thunk.reg, . - __i686.get_pc_thunk.reg;                 \
 146   .previous;                                                                  \
 147   .endif;                                                                     \
 148   call __i686.get_pc_thunk.reg
 149
 150 # define LOAD_PIC_REG(reg) \
 151   SETUP_PIC_REG(reg); addl $_GLOBAL_OFFSET_TABLE_, %e##reg
 152
 153 #else
 154 #define JUMPTARGET(name)        name
 155 #define SYSCALL_PIC_SETUP       /* Nothing.  */
 156 #endif
 157
 158 /* Local label name for asm code. */
 159 #ifndef L
 160 #ifdef HAVE_ELF
 161 #define L(name)         .L##name
 162 #else
 163 #define L(name)         name
 164 #endif
 165 #endif
 166
 167 #endif  /* __ASSEMBLER__ */