drm: Import drm_fixed.h from Linux 3.8

sys/dev/drm2/drm_fixed.h

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2009 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: Dave Airlie
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#ifndef DRM_FIXED_H
+#define DRM_FIXED_H
+
+typedef union dfixed {
+	u32 full;
+} fixed20_12;
+
+
+#define dfixed_const(A) (u32)(((A) << 12))/*  + ((B + 0.000122)*4096)) */
+#define dfixed_const_half(A) (u32)(((A) << 12) + 2048)
+#define dfixed_const_666(A) (u32)(((A) << 12) + 2731)
+#define dfixed_const_8(A) (u32)(((A) << 12) + 3277)
+#define dfixed_mul(A, B) ((u64)((u64)(A).full * (B).full + 2048) >> 12)
+#define dfixed_init(A) { .full = dfixed_const((A)) }
+#define dfixed_init_half(A) { .full = dfixed_const_half((A)) }
+#define dfixed_trunc(A) ((A).full >> 12)
+#define dfixed_frac(A) ((A).full & ((1 << 12) - 1))
+
+static inline u32 dfixed_floor(fixed20_12 A)
+{
+	u32 non_frac = dfixed_trunc(A);
+
+	return dfixed_const(non_frac);
+}
+
+static inline u32 dfixed_ceil(fixed20_12 A)
+{
+	u32 non_frac = dfixed_trunc(A);
+
+	if (A.full > dfixed_const(non_frac))
+		return dfixed_const(non_frac + 1);
+	else
+		return dfixed_const(non_frac);
+}
+
+static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B)
+{
+	u64 tmp = ((u64)A.full << 13);
+
+	do_div(tmp, B.full);
+	tmp += 1;
+	tmp /= 2;
+	return lower_32_bits(tmp);
+}
+#endif