add m68k port

three ABIs are supported: the default with 68881 80-bit fpu format and
results returned in floating point registers, softfloat-only with the
same format, and coldfire fpu with IEEE single/double only. only the
first is tested at all, and only under qemu which has fpu emulation
bugs.

basic functionality smoke tests have been performed for the most
common arch-specific breakage via libc-test and qemu user-level
emulation. some sysvipc failures remain, but are shared with other big
endian archs and will be fixed separately.

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/m68k/atomic_arch.h b/arch/m68k/atomic_arch.h
new file mode 100644
index 00000000..b369649a
--- /dev/null
+++ b/arch/m68k/atomic_arch.h
@@ -0,0 +1,8 @@
+#define a_cas a_cas
+static inline int a_cas(volatile int *p, int t, int s)
+{
+	__asm__ __volatile__ (
+		"cas.l %0, %2, (%1)"
+		: "+d"(t) : "a"(p), "d"(s) : "memory", "cc");
+	return t;
+}