include/drm/drm_fixed.h

   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 #ifndef DRM_FIXED_H
  25 #define DRM_FIXED_H
  26
  27 typedef union dfixed {
  28         u32 full;
  29 } fixed20_12;
  30
  31
  32 #define dfixed_const(A) (u32)(((A) << 12))/*  + ((B + 0.000122)*4096)) */
  33 #define dfixed_const_half(A) (u32)(((A) << 12) + 2048)
  34 #define dfixed_const_666(A) (u32)(((A) << 12) + 2731)
  35 #define dfixed_const_8(A) (u32)(((A) << 12) + 3277)
  36 #define dfixed_mul(A, B) ((u64)((u64)(A).full * (B).full + 2048) >> 12)
  37 #define dfixed_init(A) { .full = dfixed_const((A)) }
  38 #define dfixed_init_half(A) { .full = dfixed_const_half((A)) }
  39 #define dfixed_trunc(A) ((A).full >> 12)
  40 #define dfixed_frac(A) ((A).full & ((1 << 12) - 1))
  41
  42 static inline u32 dfixed_floor(fixed20_12 A)
  43 {
  44         u32 non_frac = dfixed_trunc(A);
  45
  46         return dfixed_const(non_frac);
  47 }
  48
  49 static inline u32 dfixed_ceil(fixed20_12 A)
  50 {
  51         u32 non_frac = dfixed_trunc(A);
  52
  53         if (A.full > dfixed_const(non_frac))
  54                 return dfixed_const(non_frac + 1);
  55         else
  56                 return dfixed_const(non_frac);
  57 }
  58
  59 static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B)
  60 {
  61         u64 tmp = ((u64)A.full << 13);
  62
  63         do_div(tmp, B.full);
  64         tmp += 1;
  65         tmp /= 2;
  66         return lower_32_bits(tmp);
  67 }
  68 #endif