linux/include/drm/drm_fixed.h
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   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
  27typedef 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
  42static inline u32 dfixed_floor(fixed20_12 A)
  43{
  44        u32 non_frac = dfixed_trunc(A);
  45
  46        return dfixed_const(non_frac);
  47}
  48
  49static 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
  59static 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
  69
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