superh port

1 files changed, 146 insertions, 0 deletions

diff --git a/arch/superh/src/atomic.c b/arch/superh/src/atomic.c
new file mode 100644
index 00000000..d29b0538
--- /dev/null
+++ b/arch/superh/src/atomic.c
@@ -0,0 +1,146 @@
+#include "libc.h"
+
+#define LLSC_CLOBBERS   "r0", "t", "memory"
+#define LLSC_START(mem)            \
+	"0:	movli.l @" mem ", r0\n"
+#define LLSC_END(mem)              \
+	"1:	movco.l r0, @" mem "\n"    \
+	"	bf 0b\n"                   \
+	"	synco\n"
+
+/* gusa is a hack in the kernel which lets you create a sequence of instructions
+ * which will be restarted if the process is preempted in the middle of the
+ * sequence. It will do for implementing atomics on non-smp systems. ABI is:
+ * r0  = address of first instruction after the atomic sequence
+ * r1  = original stack pointer
+ * r15 = -1 * length of atomic sequence in bytes
+ */
+#define GUSA_CLOBBERS   "r0", "r1", "memory"
+#define GUSA_START(mem,old,nop)    \
+	"	.align 2\n"                \
+	"	mova 1f, r0\n"             \
+	nop                            \
+	"	mov r15, r1\n"             \
+	"	mov #(0f-1f), r15\n"       \
+	"0:	mov.l @" mem ", " old "\n"
+/* the target of mova must be 4 byte aligned, so we may need a nop */
+#define GUSA_START_ODD(mem,old)  GUSA_START(mem,old,"")
+#define GUSA_START_EVEN(mem,old) GUSA_START(mem,old,"\tnop\n")
+#define GUSA_END(mem,new)          \
+	"	mov.l " new ", @" mem "\n" \
+	"1:	mov r1, r15\n"
+
+#define CPU_HAS_LLSC 0x0040
+
+int __sh_cas(volatile int *p, int t, int s)
+{
+	int old;
+	if (__hwcap & CPU_HAS_LLSC) {
+		__asm__ __volatile__(
+			LLSC_START("%1")
+			"	mov r0, %0\n"
+			"	cmp/eq %0, %2\n"
+			"	bf 1f\n"
+			"	mov %3, r0\n"
+			LLSC_END("%1")
+			: "=&r"(old) : "r"(p), "r"(t), "r"(s) : LLSC_CLOBBERS);
+	} else {
+		__asm__ __volatile__(
+			GUSA_START_EVEN("%1", "%0")
+			"	cmp/eq %0, %2\n"
+			"	bf 1f\n"
+			GUSA_END("%1", "%3")
+			: "=&r"(old) : "r"(p), "r"(t), "r"(s) : GUSA_CLOBBERS, "t");
+	}
+	return old;
+}
+
+int __sh_swap(volatile int *x, int v)
+{
+	int old;
+	if (__hwcap & CPU_HAS_LLSC) {
+		__asm__ __volatile__(
+			LLSC_START("%1")
+			"	mov r0, %0\n"
+			"	mov %2, r0\n"
+			LLSC_END("%1")
+			: "=&r"(old) : "r"(x), "r"(v) : LLSC_CLOBBERS);
+	} else {
+		__asm__ __volatile__(
+			GUSA_START_EVEN("%1", "%0")
+			GUSA_END("%1", "%2")
+			: "=&r"(old) : "r"(x), "r"(v) : GUSA_CLOBBERS);
+	}
+	return old;
+}
+
+int __sh_fetch_add(volatile int *x, int v)
+{
+	int old, dummy;
+	if (__hwcap & CPU_HAS_LLSC) {
+		__asm__ __volatile__(
+			LLSC_START("%1")
+			"	mov r0, %0\n"
+			"	add %2, r0\n"
+			LLSC_END("%1")
+			: "=&r"(old) : "r"(x), "r"(v) : LLSC_CLOBBERS);
+	} else {
+		__asm__ __volatile__(
+			GUSA_START_EVEN("%2", "%0")
+			"	mov %0, %1\n"
+			"	add %3, %1\n"
+			GUSA_END("%2", "%1")
+			: "=&r"(old), "=&r"(dummy) : "r"(x), "r"(v) : GUSA_CLOBBERS);
+	}
+	return old;
+}
+
+void __sh_store(volatile int *p, int x)
+{
+	if (__hwcap & CPU_HAS_LLSC) {
+		__asm__ __volatile__(
+			"	mov.l %1, @%0\n"
+			"	synco\n"
+			: : "r"(p), "r"(x) : "memory");
+	} else {
+		__asm__ __volatile__(
+			"	mov.l %1, @%0\n"
+			: : "r"(p), "r"(x) : "memory");
+	}
+}
+
+void __sh_and(volatile int *x, int v)
+{
+	int dummy;
+	if (__hwcap & CPU_HAS_LLSC) {
+		__asm__ __volatile__(
+			LLSC_START("%0")
+			"	and %1, r0\n"
+			LLSC_END("%0")
+			: : "r"(x), "r"(v) : LLSC_CLOBBERS);
+	} else {
+		__asm__ __volatile__(
+			GUSA_START_ODD("%1", "%0")
+			"	and %2, %0\n"
+			GUSA_END("%1", "%0")
+			: "=&r"(dummy) : "r"(x), "r"(v) : GUSA_CLOBBERS);
+	}
+}
+
+void __sh_or(volatile int *x, int v)
+{
+	int dummy;
+	if (__hwcap & CPU_HAS_LLSC) {
+		__asm__ __volatile__(
+			LLSC_START("%0")
+			"	or %1, r0\n"
+			LLSC_END("%0")
+			: : "r"(x), "r"(v) : LLSC_CLOBBERS);
+	} else {
+		__asm__ __volatile__(
+			GUSA_START_ODD("%1", "%0")
+			"	or %2, %0\n"
+			GUSA_END("%1", "%0")
+			: "=&r"(dummy) : "r"(x), "r"(v) : GUSA_CLOBBERS);
+	}
+}