210a0b9e21
Required for certain driver calculations. Code was written by Christian König and ported to the drm by me. v2: fix 64 bit divides v3: fix 64 bit for real (math64.h) Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
162 lines
3.8 KiB
C
162 lines
3.8 KiB
C
/*
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* Copyright 2009 Red Hat Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*
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* Authors: Dave Airlie
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* Christian König
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*/
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#ifndef DRM_FIXED_H
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#define DRM_FIXED_H
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#include <linux/math64.h>
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typedef union dfixed {
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u32 full;
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} fixed20_12;
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#define dfixed_const(A) (u32)(((A) << 12))/* + ((B + 0.000122)*4096)) */
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#define dfixed_const_half(A) (u32)(((A) << 12) + 2048)
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#define dfixed_const_666(A) (u32)(((A) << 12) + 2731)
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#define dfixed_const_8(A) (u32)(((A) << 12) + 3277)
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#define dfixed_mul(A, B) ((u64)((u64)(A).full * (B).full + 2048) >> 12)
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#define dfixed_init(A) { .full = dfixed_const((A)) }
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#define dfixed_init_half(A) { .full = dfixed_const_half((A)) }
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#define dfixed_trunc(A) ((A).full >> 12)
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#define dfixed_frac(A) ((A).full & ((1 << 12) - 1))
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static inline u32 dfixed_floor(fixed20_12 A)
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{
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u32 non_frac = dfixed_trunc(A);
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return dfixed_const(non_frac);
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}
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static inline u32 dfixed_ceil(fixed20_12 A)
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{
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u32 non_frac = dfixed_trunc(A);
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if (A.full > dfixed_const(non_frac))
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return dfixed_const(non_frac + 1);
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else
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return dfixed_const(non_frac);
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}
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static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B)
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{
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u64 tmp = ((u64)A.full << 13);
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do_div(tmp, B.full);
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tmp += 1;
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tmp /= 2;
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return lower_32_bits(tmp);
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}
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#define DRM_FIXED_POINT 32
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#define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT)
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#define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1)
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#define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK)
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static inline s64 drm_int2fixp(int a)
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{
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return ((s64)a) << DRM_FIXED_POINT;
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}
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static inline int drm_fixp2int(int64_t a)
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{
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return ((s64)a) >> DRM_FIXED_POINT;
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}
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static inline s64 drm_fixp_msbset(int64_t a)
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{
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unsigned shift, sign = (a >> 63) & 1;
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for (shift = 62; shift > 0; --shift)
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if ((a >> shift) != sign)
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return shift;
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return 0;
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}
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static inline s64 drm_fixp_mul(s64 a, s64 b)
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{
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unsigned shift = drm_fixp_msbset(a) + drm_fixp_msbset(b);
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s64 result;
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if (shift > 63) {
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shift = shift - 63;
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a >>= shift >> 1;
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b >>= shift >> 1;
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} else
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shift = 0;
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result = a * b;
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if (shift > DRM_FIXED_POINT)
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return result << (shift - DRM_FIXED_POINT);
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if (shift < DRM_FIXED_POINT)
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return result >> (DRM_FIXED_POINT - shift);
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return result;
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}
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static inline s64 drm_fixp_div(s64 a, s64 b)
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{
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unsigned shift = 63 - drm_fixp_msbset(a);
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s64 result;
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a <<= shift;
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if (shift < DRM_FIXED_POINT)
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b >>= (DRM_FIXED_POINT - shift);
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result = div64_s64(a, b);
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if (shift > DRM_FIXED_POINT)
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return result >> (shift - DRM_FIXED_POINT);
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return result;
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}
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static inline s64 drm_fixp_exp(s64 x)
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{
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s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000);
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s64 sum = DRM_FIXED_ONE, term, y = x;
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u64 count = 1;
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if (x < 0)
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y = -1 * x;
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term = y;
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while (term >= tolerance) {
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sum = sum + term;
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count = count + 1;
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term = drm_fixp_mul(term, div64_s64(y, count));
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}
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if (x < 0)
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sum = drm_fixp_div(1, sum);
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return sum;
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}
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#endif
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