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.

1 files changed, 53 insertions, 0 deletions

diff --git a/arch/microblaze/atomic_arch.h b/arch/microblaze/atomic_arch.h
new file mode 100644
index 00000000..1152e8cd
--- /dev/null
+++ b/arch/microblaze/atomic_arch.h
@@ -0,0 +1,53 @@
+#define a_cas a_cas
+static inline int a_cas(volatile int *p, int t, int s)
+{
+	register int old, tmp;
+	__asm__ __volatile__ (
+		"	addi %0, r0, 0\n"
+		"1:	lwx %0, %2, r0\n"
+		"	rsubk %1, %0, %3\n"
+		"	bnei %1, 1f\n"
+		"	swx %4, %2, r0\n"
+		"	addic %1, r0, 0\n"
+		"	bnei %1, 1b\n"
+		"1:	"
+		: "=&r"(old), "=&r"(tmp)
+		: "r"(p), "r"(t), "r"(s)
+		: "cc", "memory" );
+	return old;
+}
+
+#define a_swap a_swap
+static inline int a_swap(volatile int *x, int v)
+{
+	register int old, tmp;
+	__asm__ __volatile__ (
+		"	addi %0, r0, 0\n"
+		"1:	lwx %0, %2, r0\n"
+		"	swx %3, %2, r0\n"
+		"	addic %1, r0, 0\n"
+		"	bnei %1, 1b\n"
+		"1:	"
+		: "=&r"(old), "=&r"(tmp)
+		: "r"(x), "r"(v)
+		: "cc", "memory" );
+	return old;
+}
+
+#define a_fetch_add a_fetch_add
+static inline int a_fetch_add(volatile int *x, int v)
+{
+	register int new, tmp;
+	__asm__ __volatile__ (
+		"	addi %0, r0, 0\n"
+		"1:	lwx %0, %2, r0\n"
+		"	addk %0, %0, %3\n"
+		"	swx %0, %2, r0\n"
+		"	addic %1, r0, 0\n"
+		"	bnei %1, 1b\n"
+		"1:	"
+		: "=&r"(new), "=&r"(tmp)
+		: "r"(x), "r"(v)
+		: "cc", "memory" );
+	return new-v;
+}