这个crc是标准算法吗？stm32的硬件crc模块能够计算吗？

ilovepp · 发表于 2021-2-27 13:25:54

本帖最后由 ilovepp 于 2021-2-27 13:40 编辑

unsigned short crc(unsigned char *param_1,unsigned short param_2)
{
  unsigned int uVar1;
  unsigned int uVar2;
  unsigned short uVar3;
  unsigned char bVar4;
  unsigned int uVar5;
  unsigned char *pbVar6;
  short sVar7;
  unsigned char *pbVar8;

  if (param_2 == 0) {
return 0xffff;
  }
  uVar3 = param_2 & 1;
  if (param_2 == 1) {
uVar5 = 0xffff;
  }
  else {
uVar5 = 0xffff;
pbVar6 = param_1;
sVar7 = param_2 - (param_2 & 1);
do {
   pbVar8 = pbVar6 + -1;
   if ((param_2 & 1) == 0) {
      pbVar8 = pbVar6 + 1;
   }
   param_2 = param_2 - 2;
   param_1 = pbVar6 + 2;
   uVar5 = uVar5 ^ (unsigned int)*pbVar8 << 8;
   uVar2 = (uVar5 & 0xffff) << 1;
   uVar1 = uVar2 ^ 0x8005;
   if (-1 < (short)uVar5) {
      uVar1 = uVar2;
   }
   uVar5 = uVar1 << 1 ^ 0x8005;
   if (-1 < (short)uVar1) {
      uVar5 = uVar1 << 1;
   }
   uVar1 = uVar5 << 1 ^ 0x8005;
   if (-1 < (short)uVar5) {
      uVar1 = uVar5 << 1;
   }
   uVar5 = uVar1 << 1 ^ 0x8005;
   if (-1 < (short)uVar1) {
      uVar5 = uVar1 << 1;
   }
   uVar1 = uVar5 << 1 ^ 0x8005;
   if (-1 < (short)uVar5) {
      uVar1 = uVar5 << 1;
   }
   uVar5 = uVar1 << 1 ^ 0x8005;
   if (-1 < (short)uVar1) {
      uVar5 = uVar1 << 1;
   }
   uVar1 = uVar5 << 1 ^ 0x8005;
   if (-1 < (short)uVar5) {
      uVar1 = uVar5 << 1;
   }
   uVar5 = uVar1 << 1 ^ 0x8005;
   if (-1 < (short)uVar1) {
      uVar5 = uVar1 << 1;
   }
   if ((param_2 & 1) != 0) {
      pbVar6 = param_1;
   }
   uVar5 = uVar5 ^ (unsigned int)*pbVar6 << 8;
   uVar2 = (uVar5 & 0xffff) << 1;
   uVar1 = uVar2 ^ 0x8005;
   if (-1 < (short)uVar5) {
      uVar1 = uVar2;
   }
   uVar5 = uVar1 << 1 ^ 0x8005;
   if (-1 < (short)uVar1) {
      uVar5 = uVar1 << 1;
   }
   uVar1 = uVar5 << 1 ^ 0x8005;
   if (-1 < (short)uVar5) {
      uVar1 = uVar5 << 1;
   }
   uVar5 = uVar1 << 1 ^ 0x8005;
   if (-1 < (short)uVar1) {
      uVar5 = uVar1 << 1;
   }
   uVar1 = uVar5 << 1 ^ 0x8005;
   if (-1 < (short)uVar5) {
      uVar1 = uVar5 << 1;
   }
   uVar5 = uVar1 << 1 ^ 0x8005;
   if (-1 < (short)uVar1) {
      uVar5 = uVar1 << 1;
   }
   uVar1 = uVar5 << 1 ^ 0x8005;
   if (-1 < (short)uVar5) {
      uVar1 = uVar5 << 1;
   }
   uVar5 = uVar1 << 1 ^ 0x8005;
   if (-1 < (short)uVar1) {
      uVar5 = uVar1 << 1;
   }
   bVar4 = sVar7 != 2;
   pbVar6 = param_1;
   sVar7 = sVar7 + -2;
} while (bVar4);
  }
  if (uVar3 != 0) {
pbVar6 = param_1 + -1;
if ((param_2 & 1) == 0) {
   pbVar6 = param_1 + 1;
}
uVar5 = uVar5 ^ (unsigned int)*pbVar6 << 8;
uVar2 = (uVar5 & 0xffff) << 1;
uVar1 = uVar2 ^ 0x8005;
if (-1 < (short)uVar5) {
   uVar1 = uVar2;
}
uVar5 = uVar1 << 1 ^ 0x8005;
if (-1 < (short)uVar1) {
   uVar5 = uVar1 << 1;
}
uVar1 = uVar5 << 1 ^ 0x8005;
if (-1 < (short)uVar5) {
   uVar1 = uVar5 << 1;
}
uVar5 = uVar1 << 1 ^ 0x8005;
if (-1 < (short)uVar1) {
   uVar5 = uVar1 << 1;
}
uVar1 = uVar5 << 1 ^ 0x8005;
if (-1 < (short)uVar5) {
   uVar1 = uVar5 << 1;
}
uVar5 = uVar1 << 1 ^ 0x8005;
if (-1 < (short)uVar1) {
   uVar5 = uVar1 << 1;
}
uVar1 = uVar5 << 1 ^ 0x8005;
if (-1 < (short)uVar5) {
   uVar1 = uVar5 << 1;
}
uVar5 = uVar1 << 1 ^ 0x8005;
if (-1 < (short)uVar1) {
   uVar5 = uVar1 << 1;
}
  }
  return (unsigned short)uVar5;
}

zchong · 发表于 2021-2-27 14:05:27

自己测试吧

ilovepp · 发表于 2021-2-27 15:26:52

zchong 发表于 2021-2-27 14:05
自己测试吧

CRC16_MODBUS：
多项式x^16+x^15+x^2+1（0x8005），初始值0xFFFF，低位在前，高位在后，结果与0x0000异或；

蚁族 · 发表于 2021-3-1 08:44:14

crc16的计算算法

tomzbj · 发表于 2021-3-1 08:59:40

modbus吧, 写成8005的少见些, 一般是倒过来a001
怎么写得这么麻烦, 应该很简单的, 查表也没多少

zchong · 发表于 2021-3-1 09:01:51

stm32的CRC是32bit的，多项式是以太网的CRC格式，你这个是16bit的，算不了。

tomzbj · 发表于 2021-3-1 09:18:03

zchong 发表于 2021-3-1 09:01
stm32的CRC是32bit的，多项式是以太网的CRC格式，你这个是16bit的，算不了。

这是f1和f4吧, f0里的f042/f072, f3全系列, 应该都是能支持的

lusson · 发表于 2021-3-1 09:20:24

CRC的算法都是一样的，只是有几个设定选项，比如初始值，位数，多项式，输出要不要异或等。计算方法都是移位异或。

zchong · 发表于 2021-3-1 10:29:53

tomzbj 发表于 2021-3-1 09:18
这是f1和f4吧, f0里的f042/f072, f3全系列, 应该都是能支持的

可能，是我表达不严谨了，只接触过f1、f2、f4系列，其它的是不是多项式可以设置？

tomzbj · 发表于 2021-3-1 11:10:17

zchong 发表于 2021-3-1 10:29
可能，是我表达不严谨了，只接触过f1、f2、f4系列，其它的是不是多项式可以设置？ ...

对啊...
你看一下库文件, stm32*****_spi.h, 里面都有

这个crc是标准算法吗？stm32的硬件crc模块能够计算吗？

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