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      1 /*	$NetBSD: pthread_md.h,v 1.21 2023/05/25 14:30:02 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2001, 2007, 2008 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Nathan J. Williams, and by Andrew Doran.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _LIB_PTHREAD_I386_MD_H
     33 #define _LIB_PTHREAD_I386_MD_H
     34 
     35 #include <sys/ucontext.h>
     36 #include <ucontext.h>
     37 
     38 static inline unsigned long
     39 pthread__sp(void)
     40 {
     41 	unsigned long ret;
     42 	__asm("movl %%esp, %0" : "=g" (ret));
     43 
     44 	return ret;
     45 }
     46 
     47 #define pthread__uc_sp(ucp) ((ucp)->uc_mcontext.__gregs[_REG_UESP])
     48 
     49 static inline void
     50 _initcontext_u_md(ucontext_t *ucp)
     51 {
     52 	__asm ("pushfl; popl %0" : "=a" (ucp->uc_mcontext.__gregs[_REG_EFL]));
     53 	__asm ("pushl %%cs; popl %0" : "=a" (ucp->uc_mcontext.__gregs[_REG_CS]));
     54 	__asm ("movl %%ds, %0" : "=a" (ucp->uc_mcontext.__gregs[_REG_DS]));
     55 	__asm ("movl %%es, %0" : "=a" (ucp->uc_mcontext.__gregs[_REG_ES]));
     56 	__asm ("movl %%fs, %0" : "=a" (ucp->uc_mcontext.__gregs[_REG_FS]));
     57 	__asm ("movl %%gs, %0" : "=a" (ucp->uc_mcontext.__gregs[_REG_GS]));
     58 	__asm ("movl %%ss, %0" : "=a" (ucp->uc_mcontext.__gregs[_REG_SS]));
     59 }
     60 
     61 #define	_INITCONTEXT_U_MD(ucp)	_initcontext_u_md(ucp);
     62 
     63 #define	pthread__smt_pause()	__asm __volatile("rep; nop" ::: "memory")
     64 #define	pthread__smt_wait()	__asm __volatile("rep; nop" ::: "memory")
     65 
     66 /* Don't need additional memory barriers. */
     67 #define	PTHREAD__ATOMIC_IS_MEMBAR
     68 
     69 static inline void *
     70 _atomic_cas_ptr(volatile void *ptr, void *old, void *new)
     71 {
     72 	volatile uintptr_t *cast = ptr;
     73 	void *ret;
     74 
     75 	__asm __volatile ("lock; cmpxchgl %2, %1"
     76 		: "=a" (ret), "=m" (*cast)
     77 		: "r" (new), "m" (*cast), "0" (old));
     78 
     79 	return ret;
     80 }
     81 
     82 static inline void *
     83 _atomic_cas_ptr_ni(volatile void *ptr, void *old, void *new)
     84 {
     85 	volatile uintptr_t *cast = ptr;
     86 	void *ret;
     87 
     88 	__asm __volatile ("cmpxchgl %2, %1"
     89 		: "=a" (ret), "=m" (*cast)
     90 		: "r" (new), "m" (*cast), "0" (old));
     91 
     92 	return ret;
     93 }
     94 
     95 #endif /* _LIB_PTHREAD_I386_MD_H */
     96