forked from Qortal/Brooklyn
2a709f28fa
* 0day explit mitigation * Memory corruption prevention * Privilege escalation prevention * Buffer over flow prevention * File System corruption defense * Thread escape prevention This may very well be the most intensive inclusion to BrooklynR. This will not be part of an x86 suite nor it will be released as tool kit. The security core toolkit will remain part of kernel base.
36 lines
993 B
C
36 lines
993 B
C
#ifndef _LINUX_RECIPROCAL_DIV_H
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#define _LINUX_RECIPROCAL_DIV_H
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#include <linux/types.h>
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/*
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* This algorithm is based on the paper "Division by Invariant
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* Integers Using Multiplication" by Torbjörn Granlund and Peter
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* L. Montgomery.
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*
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* The assembler implementation from Agner Fog, which this code is
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* based on, can be found here:
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* http://www.agner.org/optimize/asmlib.zip
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*
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* This optimization for A/B is helpful if the divisor B is mostly
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* runtime invariant. The reciprocal of B is calculated in the
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* slow-path with reciprocal_value(). The fast-path can then just use
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* a much faster multiplication operation with a variable dividend A
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* to calculate the division A/B.
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*/
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struct reciprocal_value {
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u32 m;
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u8 sh1, sh2;
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};
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struct reciprocal_value reciprocal_value(u32 d);
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static inline u32 reciprocal_divide(u32 a, struct reciprocal_value R)
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{
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u32 t = (u32)(((u64)a * R.m) >> 32);
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return (t + ((a - t) >> R.sh1)) >> R.sh2;
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}
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#endif /* _LINUX_RECIPROCAL_DIV_H */
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