Archipelago » qemu

/*

 *  Save/restore host registers.

 *

 *  Copyright (c) 2007 CodeSourcery

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>.

 */

/* The GCC global register variable extension is used to reserve some

   host registers for use by generated code.  However only the core parts of

   the translation engine are compiled with these settings.  We must manually

   save/restore these registers when called from regular code.

   It is not sufficient to save/restore T0 et. al. as these may be declared

   with a datatype smaller than the actual register.  */

#if defined(DECLARE_HOST_REGS)

#define DO_REG(REG)                                        \

    register a_host_reg reg_AREG##REG asm(AREG##REG);        \

    volatile a_host_reg saved_AREG##REG;

#elif defined(SAVE_HOST_REGS)

#define DO_REG(REG)                                        \

    __asm__ __volatile__ ("" : "=r" (reg_AREG##REG));        \

    saved_AREG##REG = reg_AREG##REG;

#else

#define DO_REG(REG)                                     \

    reg_AREG##REG = saved_AREG##REG;                        \

    __asm__ __volatile__ ("" : : "r" (reg_AREG##REG));

#endif

#ifdef AREG0

DO_REG(0)

#endif

#ifdef AREG1

DO_REG(1)

#endif

#ifdef AREG2

DO_REG(2)

#endif

#undef SAVE_HOST_REGS

#undef DECLARE_HOST_REGS

#undef DO_REG