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解决ktime部分函数计算时unsigned long溢出 #9008

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Merged
merged 2 commits into from
May 30, 2024

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ComerLater
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@ComerLater ComerLater commented May 29, 2024

拉取/合并请求描述:(PR description)

[

为什么提交这份PR (why to submit this PR)

ktime部分函数中,计算时间所需的分辨率、振动频率等使用了unsigned long类型,但是该类型在计算会存在溢出。

你的解决方案是什么 (what is your solution)

将存在溢出的unsigned long变量类型修改为rt_uint64_t

请提供验证的bsp和config (provide the config and bsp)

  • BSP: qemu
  • .config:
  • action:

]

当前拉取/合并请求的状态 Intent for your PR

必须选择一项 Choose one (Mandatory):

  • 本拉取/合并请求是一个草稿版本 This PR is for a code-review and is intended to get feedback
  • 本拉取/合并请求是一个成熟版本 This PR is mature, and ready to be integrated into the repo

代码质量 Code Quality:

我在这个拉取/合并请求中已经考虑了 As part of this pull request, I've considered the following:

  • 已经仔细查看过代码改动的对比 Already check the difference between PR and old code
  • 代码风格正确,包括缩进空格,命名及其他风格 Style guide is adhered to, including spacing, naming and other styles
  • 没有垃圾代码,代码尽量精简,不包含#if 0代码,不包含已经被注释了的代码 All redundant code is removed and cleaned up
  • 所有变更均有原因及合理的,并且不会影响到其他软件组件代码或BSP All modifications are justified and not affect other components or BSP
  • 对难懂代码均提供对应的注释 I've commented appropriately where code is tricky
  • 代码是高质量的 Code in this PR is of high quality
  • 已经使用formatting 等源码格式化工具确保格式符合RT-Thread代码规范 This PR complies with RT-Thread code specification

@BernardXiong BernardXiong requested a review from polarvid May 30, 2024 00:44
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这部分在32位,64位下,是否是一致的?

@ComerLater
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这部分在32位,64位下,是否是一致的?

对于64bit系统,unsigned long一般就是64bit,对于32bit系统一般是32bit。

ktime这个模块中,rt_ktime_cputimer_getres,rt_ktime_cputimer_getfrq,rt_ktime_cputimer_getcnt等类似函数会涉及大数,uint32可以表示到4294967295(也就是4.2e9,目前mcu应该没有主频超过4.2Ghz),除了rt_ktime_cputimer_getres无法完整表示,frq和cnt都是够用了,另外部分运算虽然结果满足uint32,但是运算过程可能涉及到溢出,因此需要将运算过程中的数据添加ULL后缀

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polarvid commented May 30, 2024

好吧,看了一下标准,有限制 long long 类型的最小长度为 8 字节。

@BernardXiong BernardXiong merged commit 2cbe8bd into RT-Thread:master May 30, 2024
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3 participants