| #ifndef _LINUX_RECIPROCAL_DIV_H |

| #define _LINUX_RECIPROCAL_DIV_H |

| * This algorithm is based on the paper "Division by Invariant |

| * Integers Using Multiplication" by Torbjörn Granlund and Peter |

| * The assembler implementation from Agner Fog, which this code is |

| * based on, can be found here: |

| * http://www.agner.org/optimize/asmlib.zip |

| * This optimization for A/B is helpful if the divisor B is mostly |

| * runtime invariant. The reciprocal of B is calculated in the |

| * slow-path with reciprocal_value(). The fast-path can then just use |

| * a much faster multiplication operation with a variable dividend A |

| * to calculate the division A/B. |

| struct reciprocal_value { |

| struct reciprocal_value reciprocal_value(u32 d); |

| static inline u32 reciprocal_divide(u32 a, struct reciprocal_value R) |

| u32 t = (u32)(((u64)a * R.m) >> 32); |

| return (t + ((a - t) >> R.sh1)) >> R.sh2; |

| #endif /* _LINUX_RECIPROCAL_DIV_H */ |