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, 84 insertions, 0 deletions

diff --git a/src/fenv/m68k/fenv.c b/src/fenv/m68k/fenv.c
new file mode 100644
index 00000000..e60949d1
--- /dev/null
+++ b/src/fenv/m68k/fenv.c
@@ -0,0 +1,84 @@
+#include <fenv.h>
+
+#if __HAVE_68881__ || __mcffpu__
+
+static unsigned getsr()
+{
+	unsigned v;
+	__asm__ __volatile__ ("fmove.l %%fpsr,%0" : "=dm"(v));
+	return v;
+}
+
+static void setsr(unsigned v)
+{
+	__asm__ __volatile__ ("fmove.l %0,%%fpsr" : : "dm"(v));
+}
+
+static unsigned getcr()
+{
+	unsigned v;
+	__asm__ __volatile__ ("fmove.l %%fpcr,%0" : "=dm"(v));
+	return v;
+}
+
+static void setcr(unsigned v)
+{
+	__asm__ __volatile__ ("fmove.l %0,%%fpcr" : : "dm"(v));
+}
+
+int feclearexcept(int mask)
+{
+	if (mask & ~FE_ALL_EXCEPT) return -1;
+	setsr(getsr() & ~mask);
+	return 0;
+}
+
+int feraiseexcept(int mask)
+{
+	if (mask & ~FE_ALL_EXCEPT) return -1;
+	setsr(getsr() | mask);
+	return 0;
+}
+
+int fetestexcept(int mask)
+{
+	return getsr() & mask;
+}
+
+int fegetround(void)
+{
+	return getcr() & FE_UPWARD;
+}
+
+int __fesetround(int r)
+{
+	setcr((getcr() & ~FE_UPWARD) | r);
+	return 0;
+}
+
+int fegetenv(fenv_t *envp)
+{
+	envp->__control_register = getcr();
+	envp->__status_register = getsr();
+	__asm__ __volatile__ ("fmove.l %%fpiar,%0"
+		: "=dm"(envp->__instruction_address));
+	return 0;
+}
+
+int fesetenv(const fenv_t *envp)
+{
+	static const fenv_t default_env = { 0 };
+	if (envp == FE_DFL_ENV)
+		envp = &default_env;
+	setcr(envp->__control_register);
+	setsr(envp->__status_register);
+	__asm__ __volatile__ ("fmove.l %0,%%fpiar"
+		: : "dm"(envp->__instruction_address));
+	return 0;
+}
+
+#else
+
+#include "../fenv.c"
+
+#endif