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1 /*
2  *  Save/restore host registers.
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, see <http://www.gnu.org/licenses/>.
18  */
19 
20 /* The GCC global register variable extension is used to reserve some
21    host registers for use by generated code.  However only the core parts of
22    the translation engine are compiled with these settings.  We must manually
23    save/restore these registers when called from regular code.
24    It is not sufficient to save/restore T0 et. al. as these may be declared
25    with a datatype smaller than the actual register.  */
26 
27 #if defined(DECLARE_HOST_REGS)
28 
29 #define DO_REG(REG)					\
30     register host_reg_t reg_AREG##REG asm(AREG##REG);	\
31     volatile host_reg_t saved_AREG##REG;
32 
33 #elif defined(SAVE_HOST_REGS)
34 
35 #define DO_REG(REG)					\
36     __asm__ __volatile__ ("" : "=r" (reg_AREG##REG));	\
37     saved_AREG##REG = reg_AREG##REG;
38 
39 #else
40 
41 #define DO_REG(REG)                                     \
42     reg_AREG##REG = saved_AREG##REG;		        \
43     __asm__ __volatile__ ("" : : "r" (reg_AREG##REG));
44 
45 #endif
46 
47 #ifdef AREG0
48 DO_REG(0)
49 #endif
50 
51 #ifdef AREG1
52 DO_REG(1)
53 #endif
54 
55 #ifdef AREG2
56 DO_REG(2)
57 #endif
58 
59 #undef SAVE_HOST_REGS
60 #undef DECLARE_HOST_REGS
61 #undef DO_REG
62