initial import of NetBSD tree

1 files changed, 151 insertions, 0 deletions

diff --git a/sys/arch/mac68k/mac68k/fpu.c b/sys/arch/mac68k/mac68k/fpu.c
new file mode 100644
index 00000000000..847ae46a235
--- /dev/null
+++ b/sys/arch/mac68k/mac68k/fpu.c
@@ -0,0 +1,151 @@
+/*	$NetBSD: fpu.c,v 1.10 1995/08/12 04:10:37 briggs Exp $	*/
+
+/*
+ * Copyright (c) 1995 Gordon W. Ross
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ * 4. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed by Gordon Ross
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Floating Point Unit (MC68881/882/040)
+ * Probe for the FPU at autoconfig time.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/time.h>
+#include <sys/kernel.h>
+#include <sys/device.h>
+
+#include <machine/psl.h>
+#include <machine/cpu.h>
+#include <machine/frame.h>
+
+#include <setjmp.h>
+
+extern int fpu_type;
+extern int *nofault;
+
+extern int  matchbyname __P((struct device *, void *, void *));
+static void fpu_attach __P((struct device *, struct device *, void *));
+static int  fpu_probe __P((void));
+
+struct cfdriver fpucd = {
+	NULL, "fpu", matchbyname, fpu_attach,
+	DV_DULL, sizeof(struct device), 0 };
+
+static char *fpu_descr[] = {
+#ifdef	FPU_EMULATE
+	"emulator", 		/* 0 */
+#else
+	"no math support",	/* 0 */
+#endif
+	"mc68881",			/* 1 */
+	"mc68882",			/* 2 */
+	"mc68040",			/* 3 */
+	"?" };
+
+static void
+fpu_attach(parent, self, args)
+	struct device *parent;
+	struct device *self;
+	void *args;
+{
+	char *descr;
+	int enab_reg;
+
+	fpu_type = fpu_probe();
+	if ((0 <= fpu_type) && (fpu_type <= 2))
+		descr = fpu_descr[fpu_type];
+	else
+		descr = "unknown type";
+
+	printf(" (%s)\n", descr);
+}
+
+static int
+fpu_probe()
+{
+	/*
+	 * A 68881 idle frame is 28 bytes and a 68882's is 60 bytes.
+	 * We, of course, need to have enough room for either.
+	 */
+	int	fpframe[60 / sizeof(int)];
+	jmp_buf	faultbuf;
+	u_char	b;
+
+	nofault = (int *) &faultbuf;
+	if (setjmp(faultbuf)) {
+		nofault = (int *) 0;
+		return(0);
+	}
+
+	/*
+	 * Synchronize FPU or cause a fault.
+	 * This should leave the 881/882 in the IDLE state,
+	 * state, so we can determine which we have by
+	 * examining the size of the FP state frame
+	 */
+	asm("fnop");
+
+	nofault = (int *) 0;
+
+	/*
+	 * Presumably, if we're an 040 and did not take exception
+	 * above, we have an FPU.  Don't bother probing.
+	 */
+	if (mmutype == MMU_68040) {
+		return 3;
+	}
+
+	/*
+	 * Presumably, this will not cause a fault--the fnop should
+	 * have if this will.  We save the state in order to get the
+	 * size of the frame.
+	 */
+	asm("movl %0, a0; fsave a0@" : : "a" (fpframe) : "a0" );
+
+	b = *((u_char *) fpframe + 1);
+
+	/*
+	 * Now, restore a NULL state to reset the FPU.
+	 */
+	fpframe[0] = fpframe[1] = 0;
+	m68881_restore(fpframe);
+
+	/*
+	 * The size of a 68881 IDLE frame is 0x18
+	 *         and a 68882 frame is 0x38
+	 */
+	if (b == 0x18) return 1;
+	if (b == 0x38) return 2;
+
+	/*
+	 * If it's not one of the above, we have no clue what it is.
+	 */
+	return 4;
+}