记录一下linux初始化位的用法

file：main.c (VC6）

#include <stdio.h>

#ifdef WIN32
#pragma pack(1)
#define u16 unsigned short
#define __attribute__(x)
#endif

#define GDT_ENTRY_INIT(flags, base, limit) { { { \
    ((limit) & 0xffff) | (((base) & 0xffff) << 16), \
    (((base) & 0xff0000) >> 16) | (((flags) & 0xf0ff) << 8) | \
    ((limit) & 0xf0000) | ((base) & 0xff000000), \
    } } }

struct desc_struct {
    union {
        struct {
            unsigned int a;
            unsigned int b;
        };
        struct {
            u16 limit0;
            u16 base0;
            unsigned base1: 8, type: 4, s: 1, dpl: 2, p: 1;
            unsigned limit: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8;
        };
    };
}__attribute__((packed));

int main(int argc, char* argv[])
{
    struct desc_struct desc=GDT_ENTRY_INIT(0xF0FF,0xFFFFFFFF,0xFFFFF);
    printf ("limit0:%d, base0:%d, base1:%d, type:%d, s:%d, dpl:%d, p:%d, limit:%d, avl:%d, l:%d, d:%d, g:%d, base2:%d\r\n",
        desc.limit0,
        desc.base0,
        desc.base1,
        desc.type,
        desc.s,
        desc.dpl,
        desc.p,
        desc.limit,
        desc.avl,
        desc.l,
        desc.d,
        desc.g,
        desc.base2);
    return 0;
}