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/**
* \file drm_atomic.h
* Atomic operations used in the DRM which may or may not be provided by the OS.
*
* \author Eric Anholt <anholt@FreeBSD.org>
*/
/*-
* Copyright 2004 Eric Anholt
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#ifdef __OpenBSD__
#include <machine/atomic.h>
#endif
/* Many of these implementations are rather fake, but good enough. */
typedef u_int32_t atomic_t;
#ifdef __FreeBSD__
#define atomic_set(p, v) (*(p) = (v))
#define atomic_read(p) (*(p))
#define atomic_inc(p) atomic_add_int(p, 1)
#define atomic_dec(p) atomic_subtract_int(p, 1)
#define atomic_add(n, p) atomic_add_int(p, n)
#define atomic_sub(n, p) atomic_subtract_int(p, n)
#else /* __FreeBSD__ */
/* FIXME */
#define atomic_set(p, v) (*(p) = (v))
#define atomic_read(p) (*(p))
#define atomic_inc(p) (*(p) += 1)
#define atomic_dec(p) (*(p) -= 1)
#define atomic_add(n, p) (*(p) += (n))
#define atomic_sub(n, p) (*(p) -= (n))
/* FIXME */
#define atomic_add_int(p, v) *(p) += v
#define atomic_subtract_int(p, v) *(p) -= v
#ifdef __OpenBSD__
#define atomic_set_int(p, bits) atomic_setbits_int(p,bits)
#define atomic_clear_int(p, bits) atomic_clearbits_int(p,bits)
#else
#define atomic_set_int(p, bits) *(p) |= (bits)
#define atomic_clear_int(p, bits) *(p) &= ~(bits)
#endif
#endif /* !__FreeBSD__ */
#if !defined(__FreeBSD_version) || (__FreeBSD_version < 500000)
#if defined(__i386__) || defined(__amd64__)
/* The extra atomic functions from 5.0 haven't been merged to 4.x */
static __inline int
atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
{
int res = exp;
__asm __volatile (
" lock ; "
" cmpxchgl %1,%2 ; "
" setz %%al ; "
" movzbl %%al,%0 ; "
"1: "
"# atomic_cmpset_int"
: "+a" (res) /* 0 (result) */
: "r" (src), /* 1 */
"m" (*(dst)) /* 2 */
: "memory");
return (res);
}
#else /* __i386__ */
static __inline int
atomic_cmpset_int(__volatile__ u_int *dst, u_int old, u_int new)
{
int s = splhigh();
if (*dst==old) {
*dst = new;
splx(s);
return 1;
}
splx(s);
return 0;
}
#endif /* !__i386__ */
#endif /* !__FreeBSD_version || __FreeBSD_version < 500000 */
static __inline atomic_t
test_and_set_bit(u_int b, volatile void *p)
{
int s = splhigh();
unsigned int m = 1<<b;
unsigned int r = *(volatile int *)p & m;
*(volatile int *)p |= m;
splx(s);
return r;
}
static __inline void
clear_bit(u_int b, volatile void *p)
{
atomic_clear_int(((volatile u_int *)p) + (b >> 5), 1 << (b & 0x1f));
}
static __inline void
set_bit(u_int b, volatile void *p)
{
atomic_set_int(((volatile u_int *)p) + (b >> 5), 1 << (b & 0x1f));
}
static __inline int
test_bit(u_int b, volatile void *p)
{
return !!(((volatile u_int *)p)[b >> 5] & (1 << (b & 0x1f)));
}
static __inline int
find_first_zero_bit(volatile void *p, int max)
{
int b;
volatile u_int *ptr = (volatile u_int *)p;
for (b = 0; b < max; b += 32) {
if (ptr[b >> 5] != ~0) {
for (;;) {
if ((ptr[b >> 5] & (1 << (b & 0x1f))) == 0)
return b;
b++;
}
}
}
return max;
}
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