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drm_fixed.h revision 1.1.1.1 
      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
     69