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author | wm4 <wm4@nowhere> | 2015-05-11 23:20:45 +0200 |
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committer | wm4 <wm4@nowhere> | 2015-05-11 23:20:45 +0200 |
commit | cc24ec5b3cf7709bbd16a9505a6acc8156f63af1 (patch) | |
tree | b3232fbb34fb2b9bbde70e818f860e40a1286f6a /osdep/atomics.h | |
parent | e5573728c735d27fe4b879ef6890562a34d77428 (diff) | |
download | mpv-cc24ec5b3cf7709bbd16a9505a6acc8156f63af1.tar.bz2 mpv-cc24ec5b3cf7709bbd16a9505a6acc8156f63af1.tar.xz |
atomics: add atomic_fetch_and/atomic_fetch_or
As usual, we prefer plain C11 names and semantics, and have to emulate
them if C11 atomics are not available.
For the non-atomic fallback (which is just there to make code compile in
situations the atomic property is not overly important), we require a
gross hack to make the generic macros work without using compiler-
specific extensions.
Diffstat (limited to 'osdep/atomics.h')
-rw-r--r-- | osdep/atomics.h | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/osdep/atomics.h b/osdep/atomics.h index 8431211476..6997ba97b2 100644 --- a/osdep/atomics.h +++ b/osdep/atomics.h @@ -30,13 +30,14 @@ // Emulate the parts of C11 stdatomic.h needed by mpv. // Still relies on gcc/clang atomic builtins. +// The t field is a hack to make the non-atomic fallback macro mess work. -typedef struct { volatile unsigned long v; } atomic_ulong; -typedef struct { volatile int v; } atomic_int; -typedef struct { volatile _Bool v; } atomic_bool; -typedef struct { volatile long long v; } atomic_llong; -typedef struct { volatile uint_least32_t v; } atomic_uint_least32_t; -typedef struct { volatile unsigned long long v; } atomic_ullong; +typedef struct { volatile unsigned long v, t; } atomic_ulong; +typedef struct { volatile int v, t; } atomic_int; +typedef struct { volatile _Bool v, t; } atomic_bool; +typedef struct { volatile long long v, t; } atomic_llong; +typedef struct { volatile uint_least32_t v, t; } atomic_uint_least32_t; +typedef struct { volatile unsigned long long v, t; } atomic_ullong; #define ATOMIC_VAR_INIT(x) \ {.v = (x)} @@ -54,6 +55,10 @@ typedef struct { volatile unsigned long long v; } atomic_ullong; __atomic_store_n(&(p)->v, val, __ATOMIC_SEQ_CST) #define atomic_fetch_add(a, b) \ __atomic_fetch_add(&(a)->v, b, __ATOMIC_SEQ_CST) +#define atomic_fetch_and(a, b) \ + __atomic_fetch_and(&(a)->v, b, __ATOMIC_SEQ_CST) +#define atomic_fetch_or(a, b) \ + __atomic_fetch_or(&(a)->v, b, __ATOMIC_SEQ_CST) #define atomic_compare_exchange_strong(a, b, c) \ __atomic_compare_exchange_n(&(a)->v, b, c, 0, __ATOMIC_SEQ_CST, \ __ATOMIC_SEQ_CST) @@ -66,6 +71,10 @@ typedef struct { volatile unsigned long long v; } atomic_ullong; (__sync_synchronize(), (p)->v = (val), __sync_synchronize()) #define atomic_fetch_add(a, b) \ __sync_fetch_and_add(&(a)->v, b) +#define atomic_fetch_and(a, b) \ + __sync_fetch_and_and(&(a)->v, b) +#define atomic_fetch_or(a, b) \ + __sync_fetch_and_or(&(a)->v, b) // Assumes __sync_val_compare_and_swap is "strong" (using the C11 meaning). #define atomic_compare_exchange_strong(p, old, new) \ ({ __typeof__((p)->v) val_ = __sync_val_compare_and_swap(&(p)->v, *(old), new); \ @@ -79,7 +88,11 @@ typedef struct { volatile unsigned long long v; } atomic_ullong; // a serious dependency on working atomics, so this is barely ok. #define atomic_load(p) ((p)->v) #define atomic_store(p, val) ((p)->v = (val)) -#define atomic_fetch_add(a, b) (((a)->v += (b)) - (b)) +#define atomic_fetch_op_(a, b, op) \ + ((a)->t = (a)->v, (a)->v = (a)->v op (b), (a)->t) +#define atomic_fetch_add(a, b) atomic_fetch_op_(a, b, +) +#define atomic_fetch_and(a, b) atomic_fetch_op_(a, b, &) +#define atomic_fetch_or(a, b) atomic_fetch_op_(a, b, |) #define atomic_compare_exchange_strong(p, old, new) \ ((p)->v == *(old) ? ((p)->v = (new), 1) : (*(old) = (p)->v, 0)) |