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On the m68k, the most efficient type for __cpu_simple_lock_t is 

an unsigned char, since that is what the `tas' instruction uses.

While I'm here, implement the __cpu_simple_lock family of routines.
Why?  One, because they're easy.  Two, so Steve can get master/slave
MVME systems talking across the backplane.  :-)
This commit is contained in:
thorpej 2000-05-02 05:17:45 +00:00
parent 6f2260a0ca
commit 39f8e55cfc
1 changed files with 51 additions and 3 deletions
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54
sys/arch/m68k/include/lock.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: lock.h,v 1.2 2000/05/02 04:41:07 thorpej Exp $ */
/* $NetBSD: lock.h,v 1.3 2000/05/02 05:17:45 thorpej Exp $ */
/*-
* Copyright (c) 2000 The NetBSD Foundation, Inc.
@ -43,9 +43,57 @@
#ifndef _M68K_LOCK_H_
#define _M68K_LOCK_H_
typedef __volatile int __cpu_simple_lock_t;
typedef __volatile unsigned char __cpu_simple_lock_t;
#define __SIMPLELOCK_LOCKED 1
#define __SIMPLELOCK_LOCKED 0x80 /* result of `tas' insn */
#define __SIMPLELOCK_UNLOCKED 0
static __inline void __cpu_simple_lock_init __P((__cpu_simple_lock_t *))
__attribute__((__unused__));
static __inline void __cpu_simple_lock __P((__cpu_simple_lock_t *))
__attribute__((__unused__));
static __inline int __cpu_simple_lock_try __P((__cpu_simple_lock_t *))
__attribute__((__unused__));
static __inline void __cpu_simple_unlock __P((__cpu_simple_lock_t *))
__attribute__((__unused__));
static __inline void
__cpu_simple_lock_init(__cpu_simple_lock_t *alp)
{
*alp = __SIMPLELOCK_UNLOCKED;
}
static __inline void
__cpu_simple_lock(__cpu_simple_lock_t *alp)
{
__asm __volatile(
"1: tas %0 \n"
" jne 1b \n"
: "=m" (*alp));
}
static __inline int
__cpu_simple_lock_try(__cpu_simple_lock_t *alp)
{
int __rv = 1;
__asm __volatile(
" tas %0 \n"
" jeq 1f \n"
" moveq #0, %1 \n"
"1: \n"
: "=m" (*alp), "=d" (__rv));
return (__rv);
}
static __inline void
__cpu_simple_unlock(__cpu_simple_lock_t *alp)
{
*alp = __SIMPLELOCK_UNLOCKED;
}
#endif /* _M68K_LOCK_H_ */