14. [Protected Mode] the TSS task segments

1.TSS structure:

　　TSS is not a register, it is a memory; (contains all registers)

 

 

 2.TSS role:

If a thread switch switching registers necessarily so;

 

 3.CPU how to find the TSS memory block it? Segment register by TaskRegister 

 

　　

Value TaskRegister segment register is loaded when the CPU starts out by the GDT TSS Descrptor (descriptor);

 

4.TSS Descriptor (TSS descriptor)

 

If Type 1001 (9), when the description is not loaded into the segment descriptor register TR

If the Type is 1011 (B) described when the segment descriptor is loaded into register TR

 

 

5.TR register read:
　　

6. Review TR registers:

 

　　　　　　　　　　

 Testing laboratories:

7. experimental ideas

• Written entry function tests
• TSS structure
• Design and installation TSS descriptor

Construction TSS:

　　

char st[10] = {0}; 
TSS tss = {// tss的地址根据执行代码自己组合
    0x00000000,//link
    (DWORD)st,//esp0
    0x00000010,//ss0
    0x00000000,//esp1
    0x00000000,//ss1
    0x00000000,//esp2
    0x00000000,//ss2
    0x00000000,//cr3
    0x0040fad0,//eip   必填项，不然执行完后cpu不知道回来从哪开始执行
    0x00000000,//eflags
    0x00000000,//eax
    0x00000000,//ecx
    0x00000000,//edx
    0x00000000,//ebx
    (DWORD)st,//esp
    0x00000000,//ebp
    0x00000000,//esi
    0x00000000,//edi
    0x00000023,//es  
    0x00000008,//cs  
    0x00000010,//ss
    0x00000023,//ds
    0x00000030,//fs
    0x00000000,//gs
    0x00000000,//ldt
    0x20ac0000
};