xref: /freebsd/sys/dev/drm2/drm_fixed.h (revision 3bdf775801b218aa5a89564839405b122f4b233e)
1 /*
2  * Copyright 2009 Red Hat Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  *
22  * Authors: Dave Airlie
23  */
24 
25 #include <sys/cdefs.h>
26 __FBSDID("$FreeBSD$");
27 
28 #ifndef DRM_FIXED_H
29 #define DRM_FIXED_H
30 
31 typedef union dfixed {
32 	u32 full;
33 } fixed20_12;
34 
35 
36 #define dfixed_const(A) (u32)(((A) << 12))/*  + ((B + 0.000122)*4096)) */
37 #define dfixed_const_half(A) (u32)(((A) << 12) + 2048)
38 #define dfixed_const_666(A) (u32)(((A) << 12) + 2731)
39 #define dfixed_const_8(A) (u32)(((A) << 12) + 3277)
40 #define dfixed_mul(A, B) ((u64)((u64)(A).full * (B).full + 2048) >> 12)
41 #define dfixed_init(A) { .full = dfixed_const((A)) }
42 #define dfixed_init_half(A) { .full = dfixed_const_half((A)) }
43 #define dfixed_trunc(A) ((A).full >> 12)
44 #define dfixed_frac(A) ((A).full & ((1 << 12) - 1))
45 
46 static inline u32 dfixed_floor(fixed20_12 A)
47 {
48 	u32 non_frac = dfixed_trunc(A);
49 
50 	return dfixed_const(non_frac);
51 }
52 
53 static inline u32 dfixed_ceil(fixed20_12 A)
54 {
55 	u32 non_frac = dfixed_trunc(A);
56 
57 	if (A.full > dfixed_const(non_frac))
58 		return dfixed_const(non_frac + 1);
59 	else
60 		return dfixed_const(non_frac);
61 }
62 
63 static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B)
64 {
65 	u64 tmp = ((u64)A.full << 13);
66 
67 	do_div(tmp, B.full);
68 	tmp += 1;
69 	tmp /= 2;
70 	return lower_32_bits(tmp);
71 }
72 #endif
73