hostregs_helper.h

   1 /*
   2  *  Save/restore host registrs.
   3  *
   4  *  Copyright (c) 2007 CodeSourcery
   5  *
   6  * This 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 of the License, or (at your option) any later version.
  10  *
  11  * This 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 this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA  02110-1301 USA
  19  */
  20
  21 /* The GCC global register variable extension is used to reserve some
  22    host registers for use by generated code.  However only the core parts of
  23    the translation engine are compiled with these settings.  We must manually
  24    save/restore these registers when called from regular code.
  25    It is not sufficient to save/restore T0 et. al. as these may be declared
  26    with a datatype smaller than the actual register.  */
  27
  28 #if defined(DECLARE_HOST_REGS)
  29
  30 #define DO_REG(REG)                                     \
  31     register host_reg_t reg_AREG##REG asm(AREG##REG);   \
  32     volatile host_reg_t saved_AREG##REG;
  33
  34 #elif defined(SAVE_HOST_REGS)
  35
  36 #define DO_REG(REG)                                     \
  37     __asm__ __volatile__ ("" : "=r" (reg_AREG##REG));   \
  38     saved_AREG##REG = reg_AREG##REG;
  39
  40 #else
  41
  42 #define DO_REG(REG)                                     \
  43     reg_AREG##REG = saved_AREG##REG;                    \
  44     __asm__ __volatile__ ("" : : "r" (reg_AREG##REG));
  45
  46 #endif
  47
  48 #ifdef AREG0
  49 DO_REG(0)
  50 #endif
  51
  52 #ifdef AREG1
  53 DO_REG(1)
  54 #endif
  55
  56 #ifdef AREG2
  57 DO_REG(2)
  58 #endif
  59
  60 #undef SAVE_HOST_REGS
  61 #undef DECLARE_HOST_REGS
  62 #undef DO_REG