From 583f00e0b8efe2832f63efb478a51d3ad35e92ed Mon Sep 17 00:00:00 2001 From: Nicolas Schodet Date: Sun, 7 Oct 2007 22:16:03 +0200 Subject: Included SI2E avr modules. Well, this need more works... --- digital/avr/modules/math/fixed/fixed_cosin_f824.c | 81 +++++++++++++++++++++++ 1 file changed, 81 insertions(+) create mode 100644 digital/avr/modules/math/fixed/fixed_cosin_f824.c (limited to 'digital/avr/modules/math/fixed/fixed_cosin_f824.c') diff --git a/digital/avr/modules/math/fixed/fixed_cosin_f824.c b/digital/avr/modules/math/fixed/fixed_cosin_f824.c new file mode 100644 index 00000000..d5148f42 --- /dev/null +++ b/digital/avr/modules/math/fixed/fixed_cosin_f824.c @@ -0,0 +1,81 @@ +/* fixed_cosin_f824.c */ +/* avr.math.fixed - Fixed point math module. {{{ + * + * Copyright (C) 2005 Nicolas Schodet + * + * Robot APB Team/Efrei 2006. + * Web: http://assos.efrei.fr/robot/ + * Email: robot AT efrei DOT fr + * + * 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. + * + * }}} */ +#include "common.h" +#include "fixed.h" + +/** Compute cosinus for angles between [0,pi/2]. */ +static int32_t +fixed_cos_dli (int32_t a) +{ + static const int32_t f[] = { + (1L << 24) * -26.42625678337439745096, + (1L << 24) * 60.24464137187666035919, + (1L << 24) * -85.45681720669372773226, + (1L << 24) * 64.93939402266829148905, + (1L << 24) * -19.73920880217871723738, + (1L << 24) * 1 + }; + int32_t r; + int32_t a2; + uint8_t i; + a2 = fixed_mul_f824 (a, a); + r = f[0]; + for (i = 1; i < sizeof (f) / sizeof (f[0]); i++) + r = fixed_mul_f824 (r, a2) + f[i]; + return r; +} + +/** Compute cosinus, angle f8.24, result f8.24. */ +int32_t +fixed_cos_f824 (int32_t a) +{ + a &= (1L << 24) - 1; + uint8_t z = ((uint32_t) a >> 16) & 0xc0; + if (z == 0) + return fixed_cos_dli (a); + else if (z == 1 << 6) + return -fixed_cos_dli ((1L << 23) - a); + else if (z == 2 << 6) + return -fixed_cos_dli (a & 0xff7fffff); + else + return fixed_cos_dli ((1L << 24) - a); +} + +/** Compute sinus, angle f8.24, result f8.24. */ +int32_t +fixed_sin_f824 (int32_t a) +{ + a &= (1L << 24) - 1; + uint8_t z = ((uint32_t) a >> 16) & 0xc0; + if (z == 0) + return fixed_cos_dli ((1L << 22) - a); + else if (z == 1 << 6) + return fixed_cos_dli (a - (1L << 22)); + else if (z == 2 << 6) + return -fixed_cos_dli ((1L << 23) + (1L << 22) - a); + else + return -fixed_cos_dli (a - (1L << 23) - (1L << 22)); +} + -- cgit v1.2.3