2.9~2.12 Summary of assembly language registers

1. Segment address is stored in the 8086CPU segment register, after entering a assembly instruction such as (mov ax,1234h), 8086CPU will require access to this assembly instruction corresponding to the machine code corresponding memory , and then CS Register to give the segment address , The IP register gives the offset address and finally uses the address adder to synthesize the physical address, searches for the corresponding memory address of the machine code, a memory unit occupies one byte, then sequentially reads the instruction, the memory address is sequential plus, when the reading is finished, The machine code is transmitted to the instruction buffer by the data bus, at which time the IP will increase the total number of bytes read in order to read the next instruction, and eventually executed by the actuator (equivalent to MOV ax,1234h).

2. The CPU Cs:ip the content pointed to as an instruction execution.

3. 8086CPU Execution Process:

   (1): Read instruction from the memory unit pointed to by the CS:IP, read instruction into the instruction buffer

   (2): IP points to the next instruction (go to step 1, repeat the process)

4. 8086CPU provides transfer instructions to modify the contents of the Cs,ip.

5. JMP 1000,1234:cs Register is a 1000,IP register of 1234

6. JMP ax is like mov ip,ax, jmp Legit register so JMP BX is also possible.

7. An instruction that contains all machine code in memory can be called a code snippet

Assembly Language Register 2.9~2.12 summary