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 /* The __ARM_ARCH define is provided by gcc 4.8.  Construct it otherwise.  */
  23 #ifndef __ARM_ARCH
  24 # ifdef __ARM_ARCH_2__
  25 #  define __ARM_ARCH 2
  26 # elif defined (__ARM_ARCH_3__) || defined (__ARM_ARCH_3M__)
  27 #  define __ARM_ARCH 3
  28 # elif defined (__ARM_ARCH_4__) || defined (__ARM_ARCH_4T__)
  29 #  define __ARM_ARCH 4
  30 # elif defined (__ARM_ARCH_5__) || defined (__ARM_ARCH_5E__) \
  31        || defined(__ARM_ARCH_5T__) || defined(__ARM_ARCH_5TE__) \
  32        || defined(__ARM_ARCH_5TEJ__)
  33 #  define __ARM_ARCH 5
  34 # elif defined (__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) \
  35        || defined (__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) \
  36        || defined (__ARM_ARCH_6K__) || defined(__ARM_ARCH_6T2__)
  37 #  define __ARM_ARCH 6
  38 # elif defined (__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) \
  39        || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) \
  40        || defined(__ARM_ARCH_7EM__)
  41 #  define __ARM_ARCH 7
  42 # else
  43 #  error unknown arm architecture
  44 # endif
  45 #endif
  46
  47 #if __ARM_ARCH > 4 || defined (__ARM_ARCH_4T__)
  48 # define ARCH_HAS_BX
  49 #endif
  50 #if __ARM_ARCH > 4
  51 # define ARCH_HAS_BLX
  52 #endif
  53 #if __ARM_ARCH > 6 || defined (__ARM_ARCH_6T2__)
  54 # define ARCH_HAS_T2
  55 #endif
  56
  57 #ifdef  __ASSEMBLER__
  58
  59 /* Syntactic details of assembler.  */
  60
  61 #define ALIGNARG(log2) log2
  62 #define ASM_SIZE_DIRECTIVE(name) .size name,.-name
  63
  64 #define PLTJMP(_x)      _x##(PLT)
  65
  66 #ifdef ARCH_HAS_BX
  67 # define BX(R)          bx      R
  68 # define BXC(C, R)      bx##C   R
  69 # ifdef ARCH_HAS_BLX
  70 #  define BLX(R)        blx     R
  71 # else
  72 #  define BLX(R)        mov     lr, pc; bx R
  73 # endif
  74 #else
  75 # define BX(R)          mov     pc, R
  76 # define BXC(C, R)      mov##C  pc, R
  77 # define BLX(R)         mov     lr, pc; mov pc, R
  78 #endif
  79
  80 #define DO_RET(R)       BX(R)
  81 #define RETINSTR(C, R)  BXC(C, R)
  82
  83 /* Define an entry point visible from C.  */
  84 #define ENTRY(name)                                     \
  85         .globl  C_SYMBOL_NAME(name);                    \
  86         .type   C_SYMBOL_NAME(name),%function;          \
  87         .align  ALIGNARG(4);                            \
  88   C_LABEL(name)                                         \
  89         CFI_SECTIONS;                                   \
  90         cfi_startproc;                                  \
  91         CALL_MCOUNT
  92
  93 #define CFI_SECTIONS                                    \
  94         .cfi_sections .debug_frame
  95
  96 #undef  END
  97 #define END(name)                                       \
  98         cfi_endproc;                                    \
  99         ASM_SIZE_DIRECTIVE(name)
 100
 101 /* If compiled for profiling, call `mcount' at the start of each function.  */
 102 #ifdef  PROF
 103 /* Call __gnu_mcount_nc if GCC >= 4.4.  */
 104 #if __GNUC_PREREQ(4,4)
 105 #define CALL_MCOUNT                                     \
 106         push    {lr};                                   \
 107         cfi_adjust_cfa_offset (4);                      \
 108         cfi_rel_offset (lr, 0);                         \
 109         bl      PLTJMP(mcount);                         \
 110         cfi_adjust_cfa_offset (-4);                     \
 111         cfi_restore (lr)
 112 #else /* else call _mcount */
 113 #define CALL_MCOUNT                                     \
 114         push    {lr};                                   \
 115         cfi_adjust_cfa_offset (4);                      \
 116         cfi_rel_offset (lr, 0);                         \
 117         bl      PLTJMP(mcount);                         \
 118         pops    {lr};                                   \
 119         cfi_adjust_cfa_offset (-4);                     \
 120         cfi_restore (lr)
 121 #endif
 122 #else
 123 #define CALL_MCOUNT             /* Do nothing.  */
 124 #endif
 125
 126 /* Since C identifiers are not normally prefixed with an underscore
 127    on this system, the asm identifier `syscall_error' intrudes on the
 128    C name space.  Make sure we use an innocuous name.  */
 129 #define syscall_error   __syscall_error
 130 #if __GNUC_PREREQ(4,4)
 131 #define mcount          __gnu_mcount_nc
 132 #else
 133 #define mcount          _mcount
 134 #endif
 135
 136 /* Tag_ABI_align8_preserved: This code preserves 8-byte
 137    alignment in any callee.  */
 138         .eabi_attribute 25, 1
 139 /* Tag_ABI_align8_needed: This code may require 8-byte alignment from
 140    the caller.  */
 141         .eabi_attribute 24, 1
 142
 143 /* The thumb2 encoding is reasonably complete.  Unless suppressed, use it.  */
 144         .syntax unified
 145 # if defined(__thumb2__) && !defined(NO_THUMB)
 146         .thumb
 147 #else
 148 #  undef __thumb__
 149 #  undef __thumb2__
 150         .arm
 151 # endif
 152
 153 /* Load or store to/from a pc-relative EXPR into/from R, using T.  */
 154 # ifdef __thumb2__
 155 #  define LDST_PCREL(OP, R, T, EXPR) \
 156         ldr     T, 98f;                                 \
 157         .subsection 2;                                  \
 158 98:     .word   EXPR - 99f - PC_OFS;                    \
 159         .previous;                                      \
 160 99:     add     T, T, pc;                               \
 161         OP      R, [T]
 162 # else
 163 #  define LDST_PCREL(OP, R, T, EXPR) \
 164         ldr     T, 98f;                                 \
 165         .subsection 2;                                  \
 166 98:     .word   EXPR - 99f - PC_OFS;                    \
 167         .previous;                                      \
 168 99:     OP      R, [pc, T]
 169 # endif
 170
 171 /* Cope with negative memory offsets, which thumb can't encode.
 172    Use NEGOFF_ADJ_BASE to (conditionally) alter the base register,
 173    and then NEGOFF_OFF1 to use 0 for thumb and the offset for arm,
 174    or NEGOFF_OFF2 to use A-B for thumb and A for arm.  */
 175 # ifdef __thumb2__
 176 #  define NEGOFF_ADJ_BASE(R, OFF)       add R, R, $OFF
 177 #  define NEGOFF_ADJ_BASE2(D, S, OFF)   add D, S, $OFF
 178 #  define NEGOFF_OFF1(R, OFF)           [R]
 179 #  define NEGOFF_OFF2(R, OFFA, OFFB)    [R, $((OFFA) - (OFFB))]
 180 # else
 181 #  define NEGOFF_ADJ_BASE(R, OFF)
 182 #  define NEGOFF_ADJ_BASE2(D, S, OFF)   mov D, S
 183 #  define NEGOFF_OFF1(R, OFF)           [R, $OFF]
 184 #  define NEGOFF_OFF2(R, OFFA, OFFB)    [R, $OFFA]
 185 # endif
 186
 187 /* Helper to get the TLS base pointer.  The interface is that TMP is a
 188    register that may be used to hold the LR, if necessary.  TMP may be
 189    LR itself to indicate that LR need not be saved.  The base pointer
 190    is returned in R0.  Only R0 and TMP are modified.
 191
 192    At this generic level we have no tricks to pull.  Call the ABI routine.  */
 193 # define GET_TLS(TMP)                                   \
 194         push    { r1, r2, r3, lr };                     \
 195         cfi_remember_state;                             \
 196         cfi_adjust_cfa_offset (16);                     \
 197         cfi_rel_offset (r1, 0);                         \
 198         cfi_rel_offset (r2, 4);                         \
 199         cfi_rel_offset (r3, 8);                         \
 200         cfi_rel_offset (lr, 12);                        \
 201         bl      __aeabi_read_tp;                        \
 202         pop     { r1, r2, r3, lr };                     \
 203         cfi_restore_state
 204
 205 #endif  /* __ASSEMBLER__ */
 206
 207 /* This number is the offset from the pc at the current location.  */
 208 #ifdef __thumb__
 209 # define PC_OFS  4
 210 #else
 211 # define PC_OFS  8
 212 #endif