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authorRich Felker <dalias@aerifal.cx>2016-01-21 19:08:54 +0000
committerRich Felker <dalias@aerifal.cx>2016-01-21 19:08:54 +0000
commit1315596b510189b5159e742110b504177bdd4932 (patch)
tree27159b7b95b944671454b11f36ee13308241f4b5 /arch/arm/atomic_arch.h
parentce3e24eaae91e7a90f87eb7f1edea8df5942de11 (diff)
downloadmusl-1315596b510189b5159e742110b504177bdd4932.tar.gz
refactor internal atomic.h
rather than having each arch provide its own atomic.h, there is a new shared atomic.h in src/internal which pulls arch-specific definitions from arc/$(ARCH)/atomic_arch.h. the latter can be extremely minimal, defining only a_cas or new ll/sc type primitives which the shared atomic.h will use to construct everything else. this commit avoids making heavy changes to the individual archs' atomic implementations. definitions which are identical or near-identical to what the new shared atomic.h would produce have been removed, but otherwise the changes made are just hooking up the arch-specific files to the new infrastructure. major changes to take advantage of the new system will come in subsequent commits.
Diffstat (limited to 'arch/arm/atomic_arch.h')
-rw-r--r--arch/arm/atomic_arch.h168
1 files changed, 168 insertions, 0 deletions
diff --git a/arch/arm/atomic_arch.h b/arch/arm/atomic_arch.h
new file mode 100644
index 00000000..5ab20a55
--- /dev/null
+++ b/arch/arm/atomic_arch.h
@@ -0,0 +1,168 @@
+#if __ARM_ARCH_7A__ || __ARM_ARCH_7R__ || __ARM_ARCH >= 7
+
+#define a_barrier a_barrier
+static inline void a_barrier()
+{
+ __asm__ __volatile__("dmb ish");
+}
+
+#define a_cas a_cas
+static inline int a_cas(volatile int *p, int t, int s)
+{
+ int old;
+ __asm__ __volatile__(
+ " dmb ish\n"
+ "1: ldrex %0,%3\n"
+ " cmp %0,%1\n"
+ " bne 1f\n"
+ " strex %0,%2,%3\n"
+ " cmp %0, #0\n"
+ " bne 1b\n"
+ " mov %0, %1\n"
+ "1: dmb ish\n"
+ : "=&r"(old)
+ : "r"(t), "r"(s), "Q"(*p)
+ : "memory", "cc" );
+ return old;
+}
+
+#define a_swap a_swap
+static inline int a_swap(volatile int *x, int v)
+{
+ int old, tmp;
+ __asm__ __volatile__(
+ " dmb ish\n"
+ "1: ldrex %0,%3\n"
+ " strex %1,%2,%3\n"
+ " cmp %1, #0\n"
+ " bne 1b\n"
+ " dmb ish\n"
+ : "=&r"(old), "=&r"(tmp)
+ : "r"(v), "Q"(*x)
+ : "memory", "cc" );
+ return old;
+}
+
+#define a_fetch_add a_fetch_add
+static inline int a_fetch_add(volatile int *x, int v)
+{
+ int old, tmp;
+ __asm__ __volatile__(
+ " dmb ish\n"
+ "1: ldrex %0,%3\n"
+ " add %0,%0,%2\n"
+ " strex %1,%0,%3\n"
+ " cmp %1, #0\n"
+ " bne 1b\n"
+ " dmb ish\n"
+ : "=&r"(old), "=&r"(tmp)
+ : "r"(v), "Q"(*x)
+ : "memory", "cc" );
+ return old-v;
+}
+
+#define a_inc a_inc
+static inline void a_inc(volatile int *x)
+{
+ int tmp, tmp2;
+ __asm__ __volatile__(
+ " dmb ish\n"
+ "1: ldrex %0,%2\n"
+ " add %0,%0,#1\n"
+ " strex %1,%0,%2\n"
+ " cmp %1, #0\n"
+ " bne 1b\n"
+ " dmb ish\n"
+ : "=&r"(tmp), "=&r"(tmp2)
+ : "Q"(*x)
+ : "memory", "cc" );
+}
+
+#define a_dec a_dec
+static inline void a_dec(volatile int *x)
+{
+ int tmp, tmp2;
+ __asm__ __volatile__(
+ " dmb ish\n"
+ "1: ldrex %0,%2\n"
+ " sub %0,%0,#1\n"
+ " strex %1,%0,%2\n"
+ " cmp %1, #0\n"
+ " bne 1b\n"
+ " dmb ish\n"
+ : "=&r"(tmp), "=&r"(tmp2)
+ : "Q"(*x)
+ : "memory", "cc" );
+}
+
+#define a_and a_and
+static inline void a_and(volatile int *x, int v)
+{
+ int tmp, tmp2;
+ __asm__ __volatile__(
+ " dmb ish\n"
+ "1: ldrex %0,%3\n"
+ " and %0,%0,%2\n"
+ " strex %1,%0,%3\n"
+ " cmp %1, #0\n"
+ " bne 1b\n"
+ " dmb ish\n"
+ : "=&r"(tmp), "=&r"(tmp2)
+ : "r"(v), "Q"(*x)
+ : "memory", "cc" );
+}
+
+#define a_or a_or
+static inline void a_or(volatile int *x, int v)
+{
+ int tmp, tmp2;
+ __asm__ __volatile__(
+ " dmb ish\n"
+ "1: ldrex %0,%3\n"
+ " orr %0,%0,%2\n"
+ " strex %1,%0,%3\n"
+ " cmp %1, #0\n"
+ " bne 1b\n"
+ " dmb ish\n"
+ : "=&r"(tmp), "=&r"(tmp2)
+ : "r"(v), "Q"(*x)
+ : "memory", "cc" );
+}
+
+#define a_store a_store
+static inline void a_store(volatile int *p, int x)
+{
+ __asm__ __volatile__(
+ " dmb ish\n"
+ " str %1,%0\n"
+ " dmb ish\n"
+ : "=m"(*p)
+ : "r"(x)
+ : "memory", "cc" );
+}
+
+#else
+
+int __a_cas(int, int, volatile int *) __attribute__((__visibility__("hidden")));
+#define __k_cas __a_cas
+
+#define a_barrier a_barrier
+static inline void a_barrier()
+{
+ __asm__ __volatile__("bl __a_barrier"
+ : : : "memory", "cc", "ip", "lr" );
+}
+
+#define a_cas a_cas
+static inline int a_cas(volatile int *p, int t, int s)
+{
+ int old;
+ for (;;) {
+ if (!__k_cas(t, s, p))
+ return t;
+ if ((old=*p) != t)
+ return old;
+ }
+}
+
+#endif