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56 lines
1.2 KiB
C
56 lines
1.2 KiB
C
/**
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* @file spinlock.h
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* @author fslongjin (longjin@RinGoTek.cn)
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* @brief 自旋锁
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* @version 0.1
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* @date 2022-04-07
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*
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* @copyright Copyright (c) 2022
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*
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*/
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#include "../common/glib.h"
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/**
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* @brief 定义自旋锁结构体
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*
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*/
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typedef struct
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{
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__volatile__ char lock; // 1:unlocked 0:locked
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} spinlock_t;
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/**
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* @brief 初始化自旋锁
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*
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* @param lock
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*/
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void spin_init(spinlock_t *lock)
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{
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lock->lock = 1;
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}
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/**
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* @brief 自旋锁加锁
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*
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* @param lock
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*/
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void spin_lock(spinlock_t *lock)
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{
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__asm__ __volatile__("1: \n\t"
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"lock decq %0 \n\t" // 尝试-1
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"jns 3f \n\t" // 加锁成功，跳转到步骤3
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"2: \n\t" // 加锁失败，稍后再试
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"pause \n\t"
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"cmpq $0, %0 \n\t"
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"jle 2b \n\t" // 若锁被占用，则继续重试
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"jmp 1b \n\t" // 尝试加锁
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"3:"
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: "=m"(lock->lock)::"memory");
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}
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void spin_unlock(spinlock_t * lock)
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{
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__asm__ __volatile__("movq $1, %0 \n\t"
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:"=m"(lock->lock)::"memory");
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} |