sysdeps/i386/sysdep.h

   1 /* Assembler macros for i386.
   2    Copyright (C) 1991, 92, 93, 95, 96 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 Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 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 #define ENTRY(name)                                                           \
  49   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name);                                   \
  50   ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),@function)                          \
  51   .align ALIGNARG(4);                                                         \
  52   C_LABEL(name)                                                               \
  53   CALL_MCOUNT
  54
  55 #undef  END
  56 #define END(name)                                                             \
  57   ASM_SIZE_DIRECTIVE(name)
  58
  59 /* If compiled for profiling, call `mcount' at the start of each function.  */
  60 #ifdef  PROF
  61 /* The mcount code relies on a normal frame pointer being on the stack
  62    to locate our caller, so push one just for its benefit.  */
  63 #define CALL_MCOUNT \
  64   pushl %ebp; movl %esp, %ebp; call JUMPTARGET(mcount); popl %ebp;
  65 #else
  66 #define CALL_MCOUNT             /* Do nothing.  */
  67 #endif
  68
  69 #ifdef  NO_UNDERSCORES
  70 /* Since C identifiers are not normally prefixed with an underscore
  71    on this system, the asm identifier `syscall_error' intrudes on the
  72    C name space.  Make sure we use an innocuous name.  */
  73 #define syscall_error   __syscall_error
  74 #define mcount          _mcount
  75 #endif
  76
  77 #define PSEUDO(name, syscall_name, args)                                      \
  78 lose: SYSCALL_PIC_SETUP                                                       \
  79   jmp JUMPTARGET(syscall_error)                                               \
  80   .globl syscall_error;                                                       \
  81   ENTRY (name)                                                                \
  82   DO_CALL (syscall_name, args);                                               \
  83   jb lose
  84
  85 #undef  PSEUDO_END
  86 #define PSEUDO_END(name)                                                      \
  87   END (name)
  88
  89 #ifdef PIC
  90 #define JUMPTARGET(name)        name##@PLT
  91 #define SYSCALL_PIC_SETUP \
  92     pushl %ebx;                                                               \
  93     call 0f;                                                                  \
  94 0:  popl %ebx;                                                                \
  95     addl $_GLOBAL_OFFSET_TABLE+[.-0b], %ebx;
  96 #else
  97 #define JUMPTARGET(name)        name
  98 #define SYSCALL_PIC_SETUP       /* Nothing.  */
  99 #endif
 100
 101 #endif  /* ASSEMBLER */