ref: 8be7f27b758ef9ef818f68db0d8bcb7b038eae0e
dir: /sys/src/cmd/audio/mp3dec/fixed.c/
/* * libmad - MPEG audio decoder library * Copyright (C) 2000-2004 Underbit Technologies, Inc. * * 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 * * $Id: fixed.c,v 1.13 2004/01/23 09:41:32 rob Exp $ */ # ifdef HAVE_CONFIG_H # include "config.h" # endif # include "global.h" # include "fixed.h" /* * NAME: fixed->abs() * DESCRIPTION: return absolute value of a fixed-point number */ mad_fixed_t mad_f_abs(mad_fixed_t x) { return x < 0 ? -x : x; } /* * NAME: fixed->div() * DESCRIPTION: perform division using fixed-point math */ mad_fixed_t mad_f_div(mad_fixed_t x, mad_fixed_t y) { mad_fixed_t q, r; unsigned int bits; q = mad_f_abs(x / y); if (x < 0) { x = -x; y = -y; } r = x % y; if (y < 0) { x = -x; y = -y; } if (q > mad_f_intpart(MAD_F_MAX) && !(q == -mad_f_intpart(MAD_F_MIN) && r == 0 && (x < 0) != (y < 0))) return 0; for (bits = MAD_F_FRACBITS; bits && r; --bits) { q <<= 1, r <<= 1; if (r >= y) r -= y, ++q; } /* round */ if (2 * r >= y) ++q; /* fix sign */ if ((x < 0) != (y < 0)) q = -q; return q << bits; }