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Add atomics for Watcom/x86 as inline asm

Partially fixes Bugzilla #3758.
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sezero committed Aug 18, 2017
1 parent c68d3ab commit 500378eb5288ca6381de1f8b3dde3f9f3fef50cc
Showing with 56 additions and 1 deletion.
  1. +3 −0 include/SDL_atomic.h
  2. +36 −1 src/atomic/SDL_atomic.c
  3. +17 −0 src/atomic/SDL_spinlock.c
@@ -125,6 +125,9 @@ void _ReadWriteBarrier(void);
#elif (defined(__GNUC__) && !defined(__EMSCRIPTEN__)) || (defined(__SUNPRO_C) && (__SUNPRO_C >= 0x5120))
/* This is correct for all CPUs when using GCC or Solaris Studio 12.1+. */
#define SDL_CompilerBarrier() __asm__ __volatile__ ("" : : : "memory")
#elif defined(__WATCOMC__)
extern _inline void SDL_CompilerBarrier (void);
#pragma aux SDL_CompilerBarrier = "" parm [] modify exact [];
#else
#define SDL_CompilerBarrier() \
{ SDL_SpinLock _tmp = 0; SDL_AtomicLock(&_tmp); SDL_AtomicUnlock(&_tmp); }
@@ -52,6 +52,31 @@
# endif
#endif

#if defined(__WATCOMC__) && defined(__386__)
#define HAVE_WATCOM_ATOMICS
extern _inline int _SDL_xchg_watcom(volatile int *a, int v);
#pragma aux _SDL_xchg_watcom = \
"xchg [ecx], eax" \
parm [ecx] [eax] \
value [eax] \
modify exact [eax];

extern _inline unsigned char _SDL_cmpxchg_watcom(volatile int *a, int newval, int oldval);
#pragma aux _SDL_cmpxchg_watcom = \
"lock cmpxchg [edx], ecx" \
"setz al" \
parm [edx] [ecx] [eax] \
value [al] \
modify exact [eax];

extern _inline int _SDL_xadd_watcom(volatile int *a, int v);
#pragma aux _SDL_xadd_watcom = \
"lock xadd [ecx], eax" \
parm [ecx] [eax] \
value [eax] \
modify exact [eax];
#endif /* __WATCOMC__ && __386__ */

/*
If any of the operations are not provided then we must emulate some
of them. That means we need a nice implementation of spin locks
@@ -75,7 +100,7 @@
Contributed by Bob Pendleton, bob@pendleton.com
*/

#if !defined(HAVE_MSC_ATOMICS) && !defined(HAVE_GCC_ATOMICS) && !defined(__MACOSX__) && !defined(__SOLARIS__)
#if !defined(HAVE_MSC_ATOMICS) && !defined(HAVE_GCC_ATOMICS) && !defined(__MACOSX__) && !defined(__SOLARIS__) && !defined(HAVE_WATCOM_ATOMICS)
#define EMULATE_CAS 1
#endif

@@ -105,6 +130,8 @@ SDL_AtomicCAS(SDL_atomic_t *a, int oldval, int newval)
{
#ifdef HAVE_MSC_ATOMICS
return (_InterlockedCompareExchange((long*)&a->value, (long)newval, (long)oldval) == (long)oldval);
#elif defined(HAVE_WATCOM_ATOMICS)
return (SDL_bool) _SDL_cmpxchg_watcom(&a->value, newval, oldval);
#elif defined(HAVE_GCC_ATOMICS)
return (SDL_bool) __sync_bool_compare_and_swap(&a->value, oldval, newval);
#elif defined(__MACOSX__) /* this is deprecated in 10.12 sdk; favor gcc atomics. */
@@ -136,6 +163,8 @@ SDL_AtomicCASPtr(void **a, void *oldval, void *newval)
return (_InterlockedCompareExchange((long*)a, (long)newval, (long)oldval) == (long)oldval);
#elif defined(HAVE_MSC_ATOMICS) && (!_M_IX86)
return (_InterlockedCompareExchangePointer(a, newval, oldval) == oldval);
#elif defined(HAVE_WATCOM_ATOMICS)
return (SDL_bool) _SDL_cmpxchg_watcom((int *)a, (long)newval, (long)oldval);
#elif defined(HAVE_GCC_ATOMICS)
return __sync_bool_compare_and_swap(a, oldval, newval);
#elif defined(__MACOSX__) && defined(__LP64__) /* this is deprecated in 10.12 sdk; favor gcc atomics. */
@@ -165,6 +194,8 @@ SDL_AtomicSet(SDL_atomic_t *a, int v)
{
#ifdef HAVE_MSC_ATOMICS
return _InterlockedExchange((long*)&a->value, v);
#elif defined(HAVE_WATCOM_ATOMICS)
return _SDL_xchg_watcom(&a->value, v);
#elif defined(HAVE_GCC_ATOMICS)
return __sync_lock_test_and_set(&a->value, v);
#elif defined(__SOLARIS__) && defined(_LP64)
@@ -187,6 +218,8 @@ SDL_AtomicSetPtr(void **a, void *v)
return (void *) _InterlockedExchange((long *)a, (long) v);
#elif defined(HAVE_MSC_ATOMICS) && (!_M_IX86)
return _InterlockedExchangePointer(a, v);
#elif defined(HAVE_WATCOM_ATOMICS)
return (void *) _SDL_xchg_watcom((int *)a, (long)v);
#elif defined(HAVE_GCC_ATOMICS)
return __sync_lock_test_and_set(a, v);
#elif defined(__SOLARIS__)
@@ -205,6 +238,8 @@ SDL_AtomicAdd(SDL_atomic_t *a, int v)
{
#ifdef HAVE_MSC_ATOMICS
return _InterlockedExchangeAdd((long*)&a->value, v);
#elif defined(HAVE_WATCOM_ATOMICS)
return _SDL_xadd_watcom(&a->value, v);
#elif defined(HAVE_GCC_ATOMICS)
return __sync_fetch_and_add(&a->value, v);
#elif defined(__SOLARIS__)
@@ -32,6 +32,16 @@
#include <atomic.h>
#endif

#if defined(__WATCOMC__) && defined(__386__)
SDL_COMPILE_TIME_ASSERT(locksize, 4==sizeof(SDL_SpinLock));
extern _inline int _SDL_xchg_watcom(volatile int *a, int v);
#pragma aux _SDL_xchg_watcom = \
"xchg [ecx], eax" \
parm [ecx] [eax] \
value [eax] \
modify exact [eax];
#endif /* __WATCOMC__ && __386__ */

/* This function is where all the magic happens... */
SDL_bool
SDL_AtomicTryLock(SDL_SpinLock *lock)
@@ -58,6 +68,9 @@ SDL_AtomicTryLock(SDL_SpinLock *lock)
SDL_COMPILE_TIME_ASSERT(locksize, sizeof(*lock) == sizeof(long));
return (InterlockedExchange((long*)lock, 1) == 0);

#elif defined(__WATCOMC__) && defined(__386__)
return _SDL_xchg_watcom(lock, 1) == 0;

#elif HAVE_GCC_ATOMICS || HAVE_GCC_SYNC_LOCK_TEST_AND_SET
return (__sync_lock_test_and_set(lock, 1) == 0);

@@ -119,6 +132,10 @@ SDL_AtomicUnlock(SDL_SpinLock *lock)
_ReadWriteBarrier();
*lock = 0;

#elif defined(__WATCOMC__) && defined(__386__)
SDL_CompilerBarrier ();
*lock = 0;

#elif HAVE_GCC_ATOMICS || HAVE_GCC_SYNC_LOCK_TEST_AND_SET
__sync_lock_release(lock);

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