The third chapter 8086 addressing mode and instruction system

1. Instruction judging right and wrong, the correct command to write the source and destination operand addressing mode, the instruction pointed out wrong reason (VAR1, VAR2 variables for word, L1 label) :

MOV SI (1), 100 (2) the MOV BX, VAR1 [SI]

(3) the MOV AX, BX MOV AL (4), (DX)

(5) the MOV BP, AL (6) MOV VAR1, VAR2

(7) CS, MOV AX (8) MOV DS, 0100 h

(9) MOV [BX] [SI], 1 (10) MOV AX, VAR1 + VAR2

(11) the ADD AX, LENGTH VAR1 OR BL (12), the TYPE VAR2

(13) SUB (DI), 78 h (14) MOVS VAR1, VAR2

(15) PUSH 100 h (16) POP CS

(17) XCHG AX, ES (18) MOV DS, CS

(19) JMP L1 + 5 (20) DIV AX, 10

SHL BL (21), 2 (22) MOV AL, 15 + 23

CX (24) (23) the MUL XCHG CL, [SI]

(25) ADC CS: [0100], AH (26) SBB VAR1-5154

Reference answer: (1) the MOV SI, 100; Instruction is correct, the source: number immediately addressing, objective: register addressing

(2) the MOV BX, VAR1 [SI]; Instruction is correct, the source: register addressing, relatively objective: register addressing

(3) the MOV AX, BX]; Instruction is correct, the source: register indirect addressing, objective: register addressing

(4) the MOV AL (DX); Command error, DX cannot be used as the address register

(5) the MOV BP, AL; Command error, type inconsistent

(6) MOV VAR1, VAR2; Command error, MOV instruction cannot transfer from storage to memory

(7) CS, MOV AX; Command error, CS purpose cannot be used as the operand

(8) MOV DS, 0100 h; Command error, MOV instruction cannot be immediately digital to segment register

(9) MOV [BX] [SI], 1; Command error, type

(10) MOV AX, VAR1 + VAR2; Command error, add operation can not be completed in a MOV instruction

(11) the ADD AX, LENGTH VAR1. Instruction is correct, the source: number immediately addressing, objective: register addressing

(12) OR BL, TYPE VAR2; Instruction is correct, the source: number immediately addressing, objective: register addressing

(13) SUB (DI), 78 h. Command error, type

(14) MOVS VAR1, VAR2; Instruction is correct, the source: implied addressing, objective: implicit addressing

100 h (15) PUSH; Command error, immediately number cannot be directly onto the stack

(16) POP CS; Command error, CS purpose cannot be used as the operand

(17) XCHG AX, ES; Directive, XCHG instructions cannot be used in the segment register

(18) MOV DS, CS; Directive, MOV instruction cannot from the segment registers to segment register

(19) JMP L1 + 5; Instruction is correct, within the period of direct transfer

(20) DIV AX, 10; Command error, DIV instruction format error

SHL BL (21), 2; Command error, shift instruction shift number is 1 or CL is

(22) MOV AL, 15 + 23; Instruction is correct, the source: number immediately addressing, objective: register addressing

(23) the MUL CX. Instruction is correct, the source: register addressing, objective: implicit addressing

(24) XCHG CL, [SI]; Instruction is correct, the source: register indirect addressing, objective: register addressing

(25) ADC CS: [0100], AH; Instruction is correct, the source: register addressing, objective: direct addressing

(26) SBB VAR1-5154; Instruction is correct, the source: number immediately addressing, objective: direct addressing