| #ifndef _LINUX_RECIPROCAL_DIV_H |

| #define _LINUX_RECIPROCAL_DIV_H |

| * This file describes reciprocical division. |

| * This optimizes the (A/B) problem, when A and B are two u32 |

| * and B is a known value (but not known at compile time) |

| * The math principle used is : |

| * Let RECIPROCAL_VALUE(B) be (((1LL << 32) + (B - 1))/ B) |

| * Then A / B = (u32)(((u64)(A) * (R)) >> 32) |

| * This replaces a divide by a multiply (and a shift), and |

| * is generally less expensive in CPU cycles. |

| * Computes the reciprocal value (R) for the value B of the divisor. |

| * Should not be called before each reciprocal_divide(), |

| * or else the performance is slower than a normal divide. |

| extern u32 reciprocal_value(u32 B); |

| static inline u32 reciprocal_divide(u32 A, u32 R) |

| return (u32)(((u64)A * R) >> 32); |