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求助:这段代码是什么意思?

作者：珊瑚虫　栏目：嵌入式系统

求助:这段代码是什么意思?
void TOSH_SET_PIN_DIRECTIONS(void )
{
  * (volatile unsigned CHAR *)(unsigned int )& * (volatile unsigned   CHAR *)(0x1A + 0x20) = 0x00;
  * (volatile unsigned CHAR *)(unsigned int )& * (volatile unsigned CHAR *)(0x17 + 0x20) = 0x00;
  * (volatile unsigned CHAR *)(unsigned int )& * (volatile unsigned CHAR *)(0x11 + 0x20) = 0x00;
  * (volatile unsigned CHAR *)(unsigned int )& * (volatile unsigned CHAR *)(0x02 + 0x20) = 0x02;
  * (volatile unsigned CHAR *)(unsigned int )& * (volatile unsigned CHAR *)(0x03 + 0x20) = 0x02;
  TOSH_MAKE_RED_LED_OUTPUT();
  TOSH_MAKE_YELLOW_LED_OUTPUT();
  TOSH_MAKE_GREEN_LED_OUTPUT();
  TOSH_MAKE_POT_SELECT_OUTPUT();
  TOSH_MAKE_POT_POWER_OUTPUT();

  TOSH_MAKE_PW7_OUTPUT();
  TOSH_MAKE_PW6_OUTPUT();
  TOSH_MAKE_PW5_OUTPUT();
  TOSH_MAKE_PW4_OUTPUT();
  TOSH_MAKE_PW3_OUTPUT();
  TOSH_MAKE_PW2_OUTPUT();
  TOSH_MAKE_PW1_OUTPUT();
  TOSH_MAKE_PW0_OUTPUT();

  TOSH_MAKE_RFM_CTL0_OUTPUT();
  TOSH_MAKE_RFM_CTL1_OUTPUT();
  TOSH_MAKE_RFM_TXD_OUTPUT();
  TOSH_SET_POT_POWER_PIN();

  TOSH_MAKE_FLASH_SELECT_INPUT();

  TOSH_SET_RED_LED_PIN();
  TOSH_SET_YELLOW_LED_PIN();
  TOSH_SET_GREEN_LED_PIN();

  TOSH_MAKE_BOOST_ENABLE_OUTPUT();
  TOSH_SET_BOOST_ENABLE_PIN();

  TOSH_MAKE_ONE_WIRE_INPUT();
  TOSH_SET_ONE_WIRE_PIN();
}

这是nesC编译器nc产生的中间代码文件中的一段,它的硬件平台是ATMEGA103,显然这是一段设置引脚是输入还是输出的代码,但是前几句这实在是搞不懂,如
* (volatile unsigned CHAR *)(unsigned int )& * (volatile unsigned   CHAR *)(0x1A + 0x20) = 0x00;

这是怎样的一段类型转换啊?
最终的类型是什么,volatile unsigned CHAR*?

请达人指点,谢谢啦.

2楼：	>>参与讨论
作者： computer00 于 2005/1/12 15:27:00 发布：最终类型应该是volatile unsigned CHAR *型。搞不懂，中间哪两次转换有什么用？

3楼：

>>参与讨论

作者： jxp_sun 于 2005/1/12 15:49:00 发布：

分解
* (volatile unsigned CHAR *)(unsigned int )& * (volatile unsigned   CHAR *)(0x1A + 0x20) = 0x00;

a = (volatile unsigned   CHAR *)(0x1A + 0x20)
//a = (0x1A + 0x20)存储单元里的值, 是一个CHAR pointer type, 长度为指针长度. 4 bytes ? 8 bytes?

& * 指针所纸的是地址

b =  (unsigned int )a ;

c = * (volatile unsigned CHAR *)b;

right or not?

参与讨论

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