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, 275 insertions, 0 deletions

diff --git a/src/internal/atomic.h b/src/internal/atomic.h
new file mode 100644
index 00000000..2097247e
--- /dev/null
+++ b/src/internal/atomic.h
@@ -0,0 +1,275 @@
+#ifndef _ATOMIC_H
+#define _ATOMIC_H
+
+#include <stdint.h>
+
+#include "atomic_arch.h"
+
+#ifdef a_ll
+
+#ifndef a_pre_llsc
+#define a_pre_llsc()
+#endif
+
+#ifndef a_post_llsc
+#define a_post_llsc()
+#endif
+
+#ifndef a_cas
+#define a_cas a_cas
+static inline int a_cas(volatile int *p, int t, int s)
+{
+	int old;
+	a_pre_llsc();
+	do old = a_ll(p);
+	while (old==t && !a_sc(p, s));
+	a_post_llsc();
+	return old;
+}
+#endif
+
+#ifndef a_swap
+#define a_swap a_swap
+static inline int a_swap(volatile int *p, int v)
+{
+	int old;
+	a_pre_llsc();
+	do old = a_ll(p);
+	while (!a_sc(p, v));
+	a_post_llsc();
+	return old;
+}
+#endif
+
+#ifndef a_fetch_add
+#define a_fetch_add a_fetch_add
+static inline int a_fetch_add(volatile int *p, int v)
+{
+	int old;
+	a_pre_llsc();
+	do old = a_ll(p);
+	while (!a_sc(p, (unsigned)old + v));
+	a_post_llsc();
+	return old;
+}
+#endif
+
+#ifndef a_fetch_and
+#define a_fetch_and a_fetch_and
+static inline int a_fetch_and(volatile int *p, int v)
+{
+	int old;
+	a_pre_llsc();
+	do old = a_ll(p);
+	while (!a_sc(p, old & v));
+	a_post_llsc();
+	return old;
+}
+#endif
+
+#ifndef a_fetch_or
+#define a_fetch_or a_fetch_or
+static inline int a_fetch_or(volatile int *p, int v)
+{
+	int old;
+	a_pre_llsc();
+	do old = a_ll(p);
+	while (!a_sc(p, old | v));
+	a_post_llsc();
+	return old;
+}
+#endif
+
+#endif
+
+#ifndef a_cas
+#error missing definition of a_cas
+#endif
+
+#ifndef a_swap
+#define a_swap a_swap
+static inline int a_swap(volatile int *p, int v)
+{
+	int old;
+	do old = *p;
+	while (a_cas(p, old, v) != old);
+	return old;
+}
+#endif
+
+#ifndef a_fetch_add
+#define a_fetch_add a_fetch_add
+static inline int a_fetch_add(volatile int *p, int v)
+{
+	int old;
+	do old = *p;
+	while (a_cas(p, old, (unsigned)old+v) != old);
+	return old;
+}
+#endif
+
+#ifndef a_fetch_and
+#define a_fetch_and a_fetch_and
+static inline int a_fetch_and(volatile int *p, int v)
+{
+	int old;
+	do old = *p;
+	while (a_cas(p, old, old&v) != old);
+	return old;
+}
+#endif
+#ifndef a_fetch_or
+#define a_fetch_or a_fetch_or
+static inline int a_fetch_or(volatile int *p, int v)
+{
+	int old;
+	do old = *p;
+	while (a_cas(p, old, old|v) != old);
+	return old;
+}
+#endif
+
+#ifndef a_and
+#define a_and a_and
+static inline void a_and(volatile int *p, int v)
+{
+	a_fetch_and(p, v);
+}
+#endif
+
+#ifndef a_or
+#define a_or a_or
+static inline void a_or(volatile int *p, int v)
+{
+	a_fetch_or(p, v);
+}
+#endif
+
+#ifndef a_inc
+#define a_inc a_inc
+static inline void a_inc(volatile int *p)
+{
+	a_fetch_add(p, 1);
+}
+#endif
+
+#ifndef a_dec
+#define a_dec a_dec
+static inline void a_dec(volatile int *p)
+{
+	a_fetch_add(p, -1);
+}
+#endif
+
+#ifndef a_store
+#define a_store a_store
+static inline void a_store(volatile int *p, int v)
+{
+#ifdef a_barrier
+	a_barrier();
+	*p = v;
+	a_barrier();
+#else
+	a_swap(p, v);
+#endif
+}
+#endif
+
+#ifndef a_barrier
+#define a_barrier a_barrier
+static void a_barrier()
+{
+	volatile int tmp = 0;
+	a_cas(&tmp, 0, 0);
+}
+#endif
+
+#ifndef a_spin
+#define a_spin a_barrier
+#endif
+
+#ifndef a_and_64
+#define a_and_64 a_and_64
+static inline void a_and_64(volatile uint64_t *p, uint64_t v)
+{
+	union { uint64_t v; uint32_t r[2]; } u = { v };
+	if (u.r[0]+1) a_and((int *)p, u.r[0]);
+	if (u.r[1]+1) a_and((int *)p+1, u.r[1]);
+}
+#endif
+
+#ifndef a_or_64
+#define a_or_64 a_or_64
+static inline void a_or_64(volatile uint64_t *p, uint64_t v)
+{
+	union { uint64_t v; uint32_t r[2]; } u = { v };
+	if (u.r[0]) a_or((int *)p, u.r[0]);
+	if (u.r[1]) a_or((int *)p+1, u.r[1]);
+}
+#endif
+
+#ifndef a_cas_p
+#define a_cas_p a_cas_p
+static inline void *a_cas_p(volatile void *p, void *t, void *s)
+{
+	return (void *)a_cas((volatile int *)p, (int)t, (int)s);
+}
+#endif
+
+#ifndef a_or_l
+#define a_or_l a_or_l
+static inline void a_or_l(volatile void *p, long v)
+{
+	if (sizeof(long) == sizeof(int)) a_or(p, v);
+	else a_or_64(p, v);
+}
+#endif
+
+#ifndef a_crash
+#define a_crash a_crash
+static inline void a_crash()
+{
+	*(volatile char *)0=0;
+}
+#endif
+
+#ifndef a_ctz_64
+#define a_ctz_64 a_ctz_64
+static inline int a_ctz_64(uint64_t x)
+{
+	static const char debruijn64[64] = {
+		0, 1, 2, 53, 3, 7, 54, 27, 4, 38, 41, 8, 34, 55, 48, 28,
+		62, 5, 39, 46, 44, 42, 22, 9, 24, 35, 59, 56, 49, 18, 29, 11,
+		63, 52, 6, 26, 37, 40, 33, 47, 61, 45, 43, 21, 23, 58, 17, 10,
+		51, 25, 36, 32, 60, 20, 57, 16, 50, 31, 19, 15, 30, 14, 13, 12
+	};
+	static const char debruijn32[32] = {
+		0, 1, 23, 2, 29, 24, 19, 3, 30, 27, 25, 11, 20, 8, 4, 13,
+		31, 22, 28, 18, 26, 10, 7, 12, 21, 17, 9, 6, 16, 5, 15, 14
+	};
+	if (sizeof(long) < 8) {
+		uint32_t y = x;
+		if (!y) {
+			y = x>>32;
+			return 32 + debruijn32[(y&-y)*0x076be629 >> 27];
+		}
+		return debruijn32[(y&-y)*0x076be629 >> 27];
+	}
+	return debruijn64[(x&-x)*0x022fdd63cc95386dull >> 58];
+}
+#endif
+
+#ifndef a_ctz_l
+#define a_ctz_l a_ctz_l
+static inline int a_ctz_l(unsigned long x)
+{
+	static const char debruijn32[32] = {
+		0, 1, 23, 2, 29, 24, 19, 3, 30, 27, 25, 11, 20, 8, 4, 13,
+		31, 22, 28, 18, 26, 10, 7, 12, 21, 17, 9, 6, 16, 5, 15, 14
+	};
+	if (sizeof(long) == 8) return a_ctz_64(x);
+	return debruijn32[(x&-x)*0x076be629 >> 27];
+}
+#endif
+
+#endif