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asm_single.h revision 1.1 
      1 /*	$NetBSD: asm_single.h,v 1.1 1996/09/16 06:03:58 leo Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1996 Leo Weppelman.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *      This product includes software developed by Leo Weppelman.
     18  * 4. The name of the author may not be used to endorse or promote products
     19  *    derived from this software without specific prior written permission
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 #ifndef _M68K_ASM_SINGLE_H
     34 #define _M68K_ASM_SINGLE_H
     35 /*
     36  * Provide bit manipulation macro's that resolve to a single instruction.
     37  * These can be considered atomic on single processor architectures when
     38  * no page faults can occur when acessing <var>.
     39  * There primary use is to avoid race conditions when manipulating device
     40  * registers.
     41  */
     42 
     43 #define single_inst_bset_b(var, bit)	\
     44 	asm volatile ("orb %0,%1" : : "di" ((u_char)bit), "g" (var))
     45 #define single_inst_bclr_b(var, bit)	\
     46 	asm volatile ("andb %0,%1" : : "di" ((u_char)~(bit)), "g" (var));
     47 
     48 #define single_inst_bset_w(var, bit)	\
     49 	asm volatile ("orw %0,%1" : : "di" ((u_short)bit), "g" (var))
     50 #define single_inst_bclr_w(var, bit)	\
     51 	asm volatile ("andw %0,%1" : : "di" ((u_short)~(bit)), "g" (var));
     52 
     53 #define single_inst_bset_l(var, bit)	\
     54 	asm volatile ("orl %0,%1" : : "di" ((u_long)bit), "g" (var))
     55 #define single_inst_bclr_l(var, bit)	\
     56 	asm volatile ("andl %0,%1" : : "di" ((u_long)~(bit)), "g" (var));
     57 
     58 #endif /* _M68K_ASM_SINGLE_H */
     59