linux-011之io.h头文件

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/硬件端口字节输出函数**参数:value-要输出的字节,port-端口*/#define outb(value,port)   \__asm__("outb %%al,%%dx"::"a"(value),"d"(port));/*硬件端口输入函数*参数:port-端口。返回读取的字节*/#define intb(port)                                          \ (    \ {    \ unsigned char _v;    \ _asm_ volatile("inb %%dx,%%al":"=a"(_v):"d"(port)); \ _v;    \ }\)/*带延迟的硬件端口字节输出函数 *参数:value-要输出的字节,port-端口*/#define outb_p(value,port)     \__asm__("outb %%al,%%dx\n"     \"\tjmp 1f\n"       \"1:\tjmp 1f\n"       \"1:"       \:       \:"a"(value),"d"(port)  \);       /*带延迟的硬件端口字节输入函数*参数:port-端口。返回读取字节*/#define inb_p(port)                          \ ({     \ unsigned char _v;     \ __asm__ volatile("inb %%dx,%%al\n"   \  "\tjmp 1f\n"     \  "1:\t jmp 1f\n"     \  "1:"     \  :"=a"(_v)     \  :"d"(port)     \ );\_v;\})

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