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Diffstat (limited to 'include/drm/drm_fixed.h')
| -rw-r--r-- | include/drm/drm_fixed.h | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h new file mode 100644 index 000000000..03cb89069 --- /dev/null +++ b/include/drm/drm_fixed.h @@ -0,0 +1,217 @@ +/* + * Copyright 2009 Red Hat Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + * + * Authors: Dave Airlie + * Christian König + */ +#ifndef DRM_FIXED_H +#define DRM_FIXED_H + +#include <linux/math64.h> + +typedef union dfixed { + u32 full; +} fixed20_12; + + +#define dfixed_const(A) (u32)(((A) << 12))/* + ((B + 0.000122)*4096)) */ +#define dfixed_const_half(A) (u32)(((A) << 12) + 2048) +#define dfixed_const_666(A) (u32)(((A) << 12) + 2731) +#define dfixed_const_8(A) (u32)(((A) << 12) + 3277) +#define dfixed_mul(A, B) ((u64)((u64)(A).full * (B).full + 2048) >> 12) +#define dfixed_init(A) { .full = dfixed_const((A)) } +#define dfixed_init_half(A) { .full = dfixed_const_half((A)) } +#define dfixed_trunc(A) ((A).full >> 12) +#define dfixed_frac(A) ((A).full & ((1 << 12) - 1)) + +static inline u32 dfixed_floor(fixed20_12 A) +{ + u32 non_frac = dfixed_trunc(A); + + return dfixed_const(non_frac); +} + +static inline u32 dfixed_ceil(fixed20_12 A) +{ + u32 non_frac = dfixed_trunc(A); + + if (A.full > dfixed_const(non_frac)) + return dfixed_const(non_frac + 1); + else + return dfixed_const(non_frac); +} + +static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B) +{ + u64 tmp = ((u64)A.full << 13); + + do_div(tmp, B.full); + tmp += 1; + tmp /= 2; + return lower_32_bits(tmp); +} + +#define DRM_FIXED_POINT 32 +#define DRM_FIXED_POINT_HALF 16 +#define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT) +#define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1) +#define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK) +#define DRM_FIXED_EPSILON 1LL +#define DRM_FIXED_ALMOST_ONE (DRM_FIXED_ONE - DRM_FIXED_EPSILON) + +static inline s64 drm_int2fixp(int a) +{ + return ((s64)a) << DRM_FIXED_POINT; +} + +static inline int drm_fixp2int(s64 a) +{ + return ((s64)a) >> DRM_FIXED_POINT; +} + +static inline int drm_fixp2int_round(s64 a) +{ + return drm_fixp2int(a + (1 << (DRM_FIXED_POINT_HALF - 1))); +} + +static inline int drm_fixp2int_ceil(s64 a) +{ + if (a > 0) + return drm_fixp2int(a + DRM_FIXED_ALMOST_ONE); + else + return drm_fixp2int(a - DRM_FIXED_ALMOST_ONE); +} + +static inline unsigned drm_fixp_msbset(s64 a) +{ + unsigned shift, sign = (a >> 63) & 1; + + for (shift = 62; shift > 0; --shift) + if (((a >> shift) & 1) != sign) + return shift; + + return 0; +} + +static inline s64 drm_fixp_mul(s64 a, s64 b) +{ + unsigned shift = drm_fixp_msbset(a) + drm_fixp_msbset(b); + s64 result; + + if (shift > 61) { + shift = shift - 61; + a >>= (shift >> 1) + (shift & 1); + b >>= shift >> 1; + } else + shift = 0; + + result = a * b; + + if (shift > DRM_FIXED_POINT) + return result << (shift - DRM_FIXED_POINT); + + if (shift < DRM_FIXED_POINT) + return result >> (DRM_FIXED_POINT - shift); + + return result; +} + +static inline s64 drm_fixp_div(s64 a, s64 b) +{ + unsigned shift = 62 - drm_fixp_msbset(a); + s64 result; + + a <<= shift; + + if (shift < DRM_FIXED_POINT) + b >>= (DRM_FIXED_POINT - shift); + + result = div64_s64(a, b); + + if (shift > DRM_FIXED_POINT) + return result >> (shift - DRM_FIXED_POINT); + + return result; +} + +static inline s64 drm_fixp_from_fraction(s64 a, s64 b) +{ + s64 res; + bool a_neg = a < 0; + bool b_neg = b < 0; + u64 a_abs = a_neg ? -a : a; + u64 b_abs = b_neg ? -b : b; + u64 rem; + + /* determine integer part */ + u64 res_abs = div64_u64_rem(a_abs, b_abs, &rem); + + /* determine fractional part */ + { + u32 i = DRM_FIXED_POINT; + + do { + rem <<= 1; + res_abs <<= 1; + if (rem >= b_abs) { + res_abs |= 1; + rem -= b_abs; + } + } while (--i != 0); + } + + /* round up LSB */ + { + u64 summand = (rem << 1) >= b_abs; + + res_abs += summand; + } + + res = (s64) res_abs; + if (a_neg ^ b_neg) + res = -res; + return res; +} + +static inline s64 drm_fixp_exp(s64 x) +{ + s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000); + s64 sum = DRM_FIXED_ONE, term, y = x; + u64 count = 1; + + if (x < 0) + y = -1 * x; + + term = y; + + while (term >= tolerance) { + sum = sum + term; + count = count + 1; + term = drm_fixp_mul(term, div64_s64(y, count)); + } + + if (x < 0) + sum = drm_fixp_div(DRM_FIXED_ONE, sum); + + return sum; +} + +#endif |