atom.h

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00001 /*
00002  * Copyright (C) 2001-2005 by egnite Software GmbH. All rights reserved.
00003  *
00004  * Redistribution and use in source and binary forms, with or without
00005  * modification, are permitted provided that the following conditions
00006  * are met:
00007  *
00008  * 1. Redistributions of source code must retain the above copyright
00009  *    notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *    notice, this list of conditions and the following disclaimer in the
00012  *    documentation and/or other materials provided with the distribution.
00013  * 3. Neither the name of the copyright holders nor the names of
00014  *    contributors may be used to endorse or promote products derived
00015  *    from this software without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY EGNITE SOFTWARE GMBH AND CONTRIBUTORS
00018  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00019  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00020  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL EGNITE
00021  * SOFTWARE GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00022  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00023  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
00024  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
00025  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
00026  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
00027  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00028  * SUCH DAMAGE.
00029  *
00030  * For additional information see http://www.ethernut.de/
00031  *
00032  */
00033 
00034 /*
00035  * $Log: atom.h,v $
00036  * Revision 1.6  2008/07/07 11:04:27  haraldkipp
00037  * Configurable ways of handling critical sections for ARM targets.
00038  *
00039  * Revision 1.5  2008/03/17 10:15:36  haraldkipp
00040  * Added memory and cc clobbers to NutEnter/ExitCritical. This keeps
00041  * compiler optimizations inside and outside of critical sections
00042  * seperated.
00043  *
00044  * Revision 1.4  2007/08/17 10:47:03  haraldkipp
00045  * Bug #1757410 fixed. NutEnter/ExitCritical destroyed ARM register R0.
00046  *
00047  * Revision 1.3  2006/03/02 20:03:39  haraldkipp
00048  * Added ICCARM inline assembly for NutEnter/ExitCritical(). Also fixed
00049  * SF 1440949 (FIQ never enabled).
00050  *
00051  * Revision 1.2  2005/07/26 15:47:06  haraldkipp
00052  * AtomicInc() and AtomicDec() are no longer required by Nut/Net.
00053  * Removed to simplify the porting job. Broken applications should
00054  * implement their own version.
00055  *
00056  * Revision 1.1  2005/06/06 10:49:35  haraldkipp
00057  * Building outside the source tree failed. All header files moved from
00058  * arch/cpu/include to include/arch/cpu.
00059  *
00060  * Revision 1.1  2005/05/27 17:41:52  drsung
00061  * Moved the file.
00062  *
00063  * Revision 1.1  2005/05/26 10:08:42  drsung
00064  * Moved the platform dependend code from include/sys/atom.h to this file.
00065  *
00066  *
00067  */
00068 
00069 #ifndef _SYS_ATOM_H_
00070 #error "Do not include this file directly. Use sys/atom.h instead!"
00071 #endif
00072 
00073 #ifdef __GNUC__
00074 
00075 #if defined(NUT_CRITICAL_NESTING)
00076 
00077 #if defined(NUT_CRITICAL_NESTING_STACK)
00078 
00079 #define NutEnterCritical() \
00080 { \
00081     int temp_; \
00082     asm volatile (             \
00083             "@ NutEnterCritical"    "\n\t" \
00084             "mrs     %0, cpsr"      "\n\t" \
00085             "stmfd   sp!, {%0}"     "\n\t" \
00086             "orr     %0, %0, #0xC0" "\n\t" \
00087             "msr     cpsr, %0"      "\n\t" \
00088             : "=r" (temp_) : : "memory", "cc"); \
00089 }
00090 
00091 #define NutExitCritical() \
00092 { \
00093     int temp_; \
00094     asm volatile (             \
00095             "@ NutExitCritical" "\n\t" \
00096             "ldmfd   sp!, {%0}" "\n\t" \
00097             "msr     cpsr, %0"  "\n\t" \
00098             : "=r" (temp_) : : "memory", "cc"); \
00099 }
00100 
00101 #else /* NUT_CRITICAL_NESTING_STACK */
00102 
00103 extern u_int critical_nesting_level;
00104 
00105 #define NutEnterCritical() \
00106 if (critical_nesting_level++ == 0) { \
00107     int temp_; \
00108     asm volatile (             \
00109             "@ NutEnterCritical"    "\n\t" \
00110             "mrs     %0, cpsr"      "\n\t" \
00111             "orr     %0, %0, #0xC0" "\n\t" \
00112             "msr     cpsr, %0"      "\n\t" \
00113             : "=r" (temp_) : : "cc"); \
00114 }
00115 
00116 #define NutExitCritical() \
00117 if (critical_nesting_level) { \
00118     int temp_; \
00119     asm volatile (             \
00120             "@ NutExitCritical"     "\n\t" \
00121             "mrs     %0, cpsr"      "\n\t" \
00122             "bic     %0, %0, #0xC0" "\n\t" \
00123             "msr     cpsr, %0"      "\n\t" \
00124             : "=r" (temp_) : : "cc"); \
00125     critical_nesting_level--; \
00126 }
00127 
00128 #endif /* NUT_CRITICAL_NESTING_STACK */
00129 
00130 #else /* NUT_CRITICAL_NESTING */
00131 
00132 #define NutEnterCritical() \
00133 { \
00134     int temp_; \
00135     asm volatile (             \
00136             "@ NutEnterCritical"    "\n\t" \
00137             "mrs     %0, cpsr"      "\n\t" \
00138             "orr     %0, %0, #0xC0" "\n\t" \
00139             "msr     cpsr, %0"      "\n\t" \
00140             : "=r" (temp_) : : "cc"); \
00141 }
00142 
00143 #define NutExitCritical() \
00144 { \
00145     int temp_; \
00146     asm volatile (             \
00147             "@ NutExitCritical"     "\n\t" \
00148             "mrs     %0, cpsr"      "\n\t" \
00149             "bic     %0, %0, #0xC0" "\n\t" \
00150             "msr     cpsr, %0"      "\n\t" \
00151             : "=r" (temp_) : : "cc"); \
00152 }
00153 
00154 #endif /* NUT_CRITICAL_NESTING */
00155 
00156 #define NutJumpOutCritical()    NutExitCritical()
00157 
00158 #else /* __IMAGECRAFT__ */
00159 
00160 #define NutEnterCritical() \
00161         asm("; NutEnterCritical\n" \
00162             "mrs r12, cpsr\n" \
00163             "orr r12, r12, #0xC0\n" \
00164             "msr cpsr_c, r12")
00165 
00166 #define NutExitCritical() \
00167         asm("; NutExitCritical\n" \
00168             "mrs r12, cpsr\n" \
00169             "bic r12, r12, #0xC0\n" \
00170             "msr cpsr_c, r12")
00171 
00172 #endif

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