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 #define ENTRY_CHK(name) ENTRY (name)
  71 #define END_CHK(name) END (name)
  72
  73 #ifdef HAVE_CPP_ASM_DEBUGINFO
  74 /* Disable that goop, because we just pass -g through to the assembler
  75    and it generates proper line number information directly.  */
  76 # define STABS_CURRENT_FILE1(name)
  77 # define STABS_CURRENT_FILE(name)
  78 # define STABS_FUN(name)
  79 # define STABS_FUN_END(name)
  80 #else
  81 /* Remove the following two lines once the gdb bug is fixed.  */
  82 #define STABS_CURRENT_FILE(name)                                              \
  83   STABS_CURRENT_FILE1 (#name)
  84 #define STABS_CURRENT_FILE1(name)                                             \
  85   1: .stabs name,100,0,0,1b;
  86 /* Emit stabs definition lines.  We use F(0,1) and define t(0,1) as `int',
  87    the same way gcc does it.  */
  88 #define STABS_FUN(name) STABS_FUN2(name, name##:F(0,1))
  89 #define STABS_FUN2(name, namestr)                                             \
  90   .stabs "int:t(0,1)=r(0,1);-2147483648;2147483647;",128,0,0,0;               \
  91   .stabs #namestr,36,0,0,name;
  92 #define STABS_FUN_END(name)                                                   \
  93   1: .stabs "",36,0,0,1b-name;
  94 #endif
  95
  96 /* If compiled for profiling, call `mcount' at the start of each function.  */
  97 #ifdef  PROF
  98 /* The mcount code relies on a normal frame pointer being on the stack
  99    to locate our caller, so push one just for its benefit.  */
 100 #define CALL_MCOUNT \
 101   pushl %ebp; cfi_adjust_cfa_offset (4); movl %esp, %ebp; \
 102   cfi_def_cfa_register (ebp); call JUMPTARGET(mcount); \
 103   popl %ebp; cfi_def_cfa (esp, 4);
 104 #else
 105 #define CALL_MCOUNT             /* Do nothing.  */
 106 #endif
 107
 108 #ifdef  NO_UNDERSCORES
 109 /* Since C identifiers are not normally prefixed with an underscore
 110    on this system, the asm identifier `syscall_error' intrudes on the
 111    C name space.  Make sure we use an innocuous name.  */
 112 #define syscall_error   __syscall_error
 113 #define mcount          _mcount
 114 #endif
 115
 116 #define PSEUDO(name, syscall_name, args)                                      \
 117   .globl syscall_error;                                                       \
 118 lose: SYSCALL_PIC_SETUP                                                       \
 119   jmp JUMPTARGET(syscall_error);                                              \
 120   ENTRY (name)                                                                \
 121   DO_CALL (syscall_name, args);                                               \
 122   jb lose
 123
 124 #undef  PSEUDO_END
 125 #define PSEUDO_END(name)                                                      \
 126   END (name)
 127
 128 #undef JUMPTARGET
 129 #ifdef PIC
 130 #define JUMPTARGET(name)        name##@PLT
 131 #define SYSCALL_PIC_SETUP \
 132     pushl %ebx;                                                               \
 133     cfi_adjust_cfa_offset (4);                                                \
 134     call 0f;                                                                  \
 135 0:  popl %ebx;                                                                \
 136     cfi_adjust_cfa_offset (-4);                                               \
 137     addl $_GLOBAL_OFFSET_TABLE+[.-0b], %ebx;
 138
 139 # define SETUP_PIC_REG(reg) \
 140   .ifndef __i686.get_pc_thunk.reg;                                            \
 141   .section .gnu.linkonce.t.__i686.get_pc_thunk.reg,"ax",@progbits;            \
 142   .globl __i686.get_pc_thunk.reg;                                             \
 143   .hidden __i686.get_pc_thunk.reg;                                            \
 144   .type __i686.get_pc_thunk.reg,@function;                                    \
 145 __i686.get_pc_thunk.reg:                                                      \
 146   movl (%esp), %e##reg;                                                       \
 147   ret;                                                                        \
 148   .size __i686.get_pc_thunk.reg, . - __i686.get_pc_thunk.reg;                 \
 149   .previous;                                                                  \
 150   .endif;                                                                     \
 151   call __i686.get_pc_thunk.reg
 152
 153 # define LOAD_PIC_REG(reg) \
 154   SETUP_PIC_REG(reg); addl $_GLOBAL_OFFSET_TABLE_, %e##reg
 155
 156 #else
 157 #define JUMPTARGET(name)        name
 158 #define SYSCALL_PIC_SETUP       /* Nothing.  */
 159 #endif
 160
 161 /* Local label name for asm code. */
 162 #ifndef L
 163 #ifdef HAVE_ELF
 164 #define L(name)         .L##name
 165 #else
 166 #define L(name)         name
 167 #endif
 168 #endif
 169
 170 #endif  /* __ASSEMBLER__ */