Edit File: drm_fixed.h
/* * 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_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_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