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 #ifndef _FIXP_ARITH_H #define _FIXP_ARITH_H /* * Simplistic fixed-point arithmetics. * Hmm, I'm probably duplicating some code :( * * Copyright (c) 2002 Johann Deneux */ /* * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * Should you need to contact me, the author, you can do so by * e-mail - mail your message to */ #include /* The type representing fixed-point values */ typedef s16 fixp_t; #define FRAC_N 8 #define FRAC_MASK ((1< 123.0 */ static inline fixp_t fixp_new(s16 a) { return a< -1.0 0x8000 -> 1.0 0x0000 -> 0.0 */ static inline fixp_t fixp_new16(s16 a) { return ((s32)a)>>(16-FRAC_N); } static inline fixp_t fixp_cos(unsigned int degrees) { int quadrant = (degrees / 90) & 3; unsigned int i = degrees % 90; if (quadrant == 1 || quadrant == 3) i = 90 - i; i >>= 1; return (quadrant == 1 || quadrant == 2)? -cos_table[i] : cos_table[i]; } static inline fixp_t fixp_sin(unsigned int degrees) { return -fixp_cos(degrees + 90); } static inline fixp_t fixp_mult(fixp_t a, fixp_t b) { return ((s32)(a*b))>>FRAC_N; } #endif