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+#ifndef fixed_h
+#define fixed_h
+/* fixed.h */
+/* 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.
+ *
+ * }}} */
+
+/* Numbers notation:
+ * [u]{i|f}x[.y]
+ * u: unsigned
+ * i: integer
+ * f: fixed point
+ * x: integral part size in bits
+ * y: fractionnal part size in bits
+ *
+ * Ex: i16: signed 16 bit word, uf8.8: unsigned fixed 8.8.
+ *
+ * Angles are mapped from [0, 2pi) to [0,1). */
+
+#ifndef HOST
+
+/* Multiply f8.24 by f8.24, return f8.24. */
+#define fixed_mul_f824(a, b) ({ \
+ uint16_t dummy; \
+ asm ("" : "=r" (dummy)); \
+ fixed_mul_f824_asm (dummy, a, b); })
+int32_t
+fixed_mul_f824_asm (uint16_t dummy, int32_t a, int32_t b);
+
+/* Divide f8.24 by f8.24, return f8.24. */
+int32_t
+fixed_div_f824 (int32_t a, int32_t b);
+
+#else /* HOST */
+
+/** Multiply f8.24 by f8.24, return f8.24. */
+#define fixed_mul_f824(a, b) (((int64_t) (a) * (int64_t) (b) \
+ + 0x800000LL) >> 24)
+
+/** Divide f8.24 by f8.24, return f8.24. */
+#define fixed_div_f824(a, b) (((int64_t) (a) << 24) / (int64_t) (b))
+
+#endif
+
+/** Compute cosinus, angle f8.24, result f8.24. */
+int32_t
+fixed_cos_f824 (int32_t a);
+
+/** Compute sinus, angle f8.24, result f8.24. */
+int32_t
+fixed_sin_f824 (int32_t a);
+
+/** Compute square root, uf24.8. */
+uint32_t
+fixed_sqrt_uf248 (uint32_t x);
+
+/** Compute square root, ui32 -> ui16. */
+uint16_t
+fixed_sqrt_ui32 (uint32_t x);
+
+#endif /* fixed_h */