ports/sysdeps/arm/sysdep.h

   1 /* Assembler macros for ARM.
   2    Copyright (C) 1997-2013 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <sysdeps/generic/sysdep.h>
  20 #include <features.h>
  21
  22 #if (!defined (__ARM_ARCH_2__) && !defined (__ARM_ARCH_3__) \
  23      && !defined (__ARM_ARCH_3M__) && !defined (__ARM_ARCH_4__))
  24 # define __USE_BX__
  25 #endif
  26
  27 #ifdef  __ASSEMBLER__
  28
  29 /* Syntactic details of assembler.  */
  30
  31 #define ALIGNARG(log2) log2
  32 #define ASM_SIZE_DIRECTIVE(name) .size name,.-name
  33
  34 #define PLTJMP(_x)      _x##(PLT)
  35
  36 /* APCS-32 doesn't preserve the condition codes across function call. */
  37 #ifdef __APCS_32__
  38 #define LOADREGS(cond, base, reglist...)\
  39         ldm##cond       base,reglist
  40 #ifdef __USE_BX__
  41 #define RETINSTR(cond, reg)     \
  42         bx##cond        reg
  43 #define DO_RET(_reg)            \
  44         bx _reg
  45 #else
  46 #define RETINSTR(cond, reg)     \
  47         mov##cond       pc, reg
  48 #define DO_RET(_reg)            \
  49         mov pc, _reg
  50 #endif
  51 #else  /* APCS-26 */
  52 #define LOADREGS(cond, base, reglist...)\
  53         ldm##cond       base,reglist^
  54 #define RETINSTR(cond, reg)     \
  55         mov##cond##s    pc, reg
  56 #define DO_RET(_reg)            \
  57         movs pc, _reg
  58 #endif
  59
  60 /* Define an entry point visible from C.  */
  61 #define ENTRY(name)                                     \
  62         .globl  C_SYMBOL_NAME(name);                    \
  63         .type   C_SYMBOL_NAME(name),%function;          \
  64         .align  ALIGNARG(4);                            \
  65   C_LABEL(name)                                         \
  66         CFI_SECTIONS;                                   \
  67         cfi_startproc;                                  \
  68         CALL_MCOUNT
  69
  70 #define CFI_SECTIONS                                    \
  71         .cfi_sections .debug_frame
  72
  73 #undef  END
  74 #define END(name)                                       \
  75         cfi_endproc;                                    \
  76         ASM_SIZE_DIRECTIVE(name)
  77
  78 /* If compiled for profiling, call `mcount' at the start of each function.  */
  79 #ifdef  PROF
  80 /* Call __gnu_mcount_nc if GCC >= 4.4.  */
  81 #if __GNUC_PREREQ(4,4)
  82 #define CALL_MCOUNT                                     \
  83         str     lr,[sp, #-4]!;                          \
  84         cfi_adjust_cfa_offset (4);                      \
  85         cfi_rel_offset (lr, 0);                         \
  86         bl      PLTJMP(mcount);                         \
  87         cfi_adjust_cfa_offset (-4);                     \
  88         cfi_restore (lr)
  89 #else /* else call _mcount */
  90 #define CALL_MCOUNT                                     \
  91         str     lr,[sp, #-4]!;                          \
  92         cfi_adjust_cfa_offset (4);                      \
  93         cfi_rel_offset (lr, 0);                         \
  94         bl      PLTJMP(mcount);                         \
  95         ldr     lr, [sp], #4;                           \
  96         cfi_adjust_cfa_offset (-4);                     \
  97         cfi_restore (lr)
  98 #endif
  99 #else
 100 #define CALL_MCOUNT             /* Do nothing.  */
 101 #endif
 102
 103 /* Since C identifiers are not normally prefixed with an underscore
 104    on this system, the asm identifier `syscall_error' intrudes on the
 105    C name space.  Make sure we use an innocuous name.  */
 106 #define syscall_error   __syscall_error
 107 #if __GNUC_PREREQ(4,4)
 108 #define mcount          __gnu_mcount_nc
 109 #else
 110 #define mcount          _mcount
 111 #endif
 112
 113 /* Tag_ABI_align8_preserved: This code preserves 8-byte
 114    alignment in any callee.  */
 115         .eabi_attribute 25, 1
 116 /* Tag_ABI_align8_needed: This code may require 8-byte alignment from
 117    the caller.  */
 118         .eabi_attribute 24, 1
 119
 120 #endif  /* __ASSEMBLER__ */