os_kernel_lab/related_info/lab0/lab0_ex3.md

#README Try below command

gcc -g -m32 lab0_ex3.c 2>&1|tee make.log

If you get gcc's error, try to read make.log and fix the bugs.

If gcc successed, then you will get a.out.

Try to answer below question.

对于如下的代码段，

...
#define STS_CG32        0xC            // 32-bit Call Gate
#define STS_IG32        0xE            // 32-bit Interrupt Gate

#define SETGATE(gate, istrap, sel, off, dpl) {            \
    (gate).gd_off_15_0 = (uint32_t)(off) & 0xffff;        \
    (gate).gd_ss = (sel);                                \
    (gate).gd_args = 0;                                    \
    (gate).gd_rsv1 = 0;                                    \
    (gate).gd_type = (istrap) ? STS_TG32 : STS_IG32;    \
    (gate).gd_s = 0;                                    \
    (gate).gd_dpl = (dpl);                                \
    (gate).gd_p = 1;                                    \
    (gate).gd_off_31_16 = (uint32_t)(off) >> 16;        \
}

 /* Gate descriptors for interrupts and traps */
 struct gatedesc {
    unsigned gd_off_15_0 : 16;        // low 16 bits of offset in segment
    unsigned gd_ss : 16;            // segment selector
    unsigned gd_args : 5;            // # args, 0 for interrupt/trap gates
    unsigned gd_rsv1 : 3;            // reserved(should be zero I guess)
    unsigned gd_type : 4;            // type(STS_{TG,IG32,TG32})
    unsigned gd_s : 1;                // must be 0 (system)
    unsigned gd_dpl : 2;            // descriptor(meaning new) privilege level
    unsigned gd_p : 1;                // Present
    unsigned gd_off_31_16 : 16;        // high bits of offset in segment
 };
 
... 

如果在其他代码段中有如下语句，

unsigned intr;
intr=8;
SETGATE(intr, 0,1,2,3);

请问执行上述指令后， intr的值是多少？