/* * 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