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
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, 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
  33 /* In ELF C symbols are asm symbols.  */
  34 #undef  NO_UNDERSCORES
  35 #define NO_UNDERSCORES
  36
  37 #else
  38
  39 #define ALIGNARG(log2) log2
  40 #define ASM_TYPE_DIRECTIVE(name,type) /* Nothing is specified.  */
  41
  42 #endif
  43
  44
  45 /* Define an entry point visible from C.  */
  46 #define ENTRY(name)                                                           \
  47   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name);                                   \
  48   ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),@function)                          \
  49   .align ALIGNARG(4);                                                         \
  50   C_LABEL(name)                                                               \
  51   CALL_MCOUNT
  52
  53 /* If compiled for profiling, call `mcount' at the start of each function.  */
  54 #ifdef  PROF
  55 /* The mcount code relies on a normal frame pointer being on the stack
  56    to locate our caller, so push one just for its benefit.  */
  57 #define CALL_MCOUNT \
  58   pushl %ebp; movl %esp, %ebp; call JUMPTARGET(mcount); popl %ebp;
  59 #else
  60 #define CALL_MCOUNT             /* Do nothing.  */
  61 #endif
  62
  63 #ifdef  NO_UNDERSCORES
  64 /* Since C identifiers are not normally prefixed with an underscore
  65    on this system, the asm identifier `syscall_error' intrudes on the
  66    C name space.  Make sure we use an innocuous name.  */
  67 #define syscall_error   __syscall_error
  68 #define mcount          _mcount
  69 #endif
  70
  71 #define PSEUDO(name, syscall_name, args)                                      \
  72 lose: SYSCALL_PIC_SETUP                                                       \
  73   jmp JUMPTARGET(syscall_error)                                               \
  74   .globl syscall_error;                                                       \
  75   ENTRY (name)                                                                \
  76   DO_CALL (syscall_name, args);                                               \
  77   jb lose
  78
  79 #ifdef PIC
  80 #define JUMPTARGET(name)        name##@PLT
  81 #define SYSCALL_PIC_SETUP \
  82     pushl %ebx;                                                               \
  83     call 0f;                                                                  \
  84 0:  popl %ebx;                                                                \
  85     addl $_GLOBAL_OFFSET_TABLE+[.-0b], %ebx;
  86 #else
  87 #define JUMPTARGET(name)        name
  88 #define SYSCALL_PIC_SETUP       /* Nothing.  */
  89 #endif
  90
  91 #endif  /* ASSEMBLER */