的数据个数。 24.(1) MOVAL,* MOV AX SEG B3 MOV ES. AX MOV DI OFFSET B3 CLD MOVCⅹ.40 REP STOSB (2)MOV AX, SEG B MOV DS. AX MOV SI OFFSET BI MOV AX SEG B3 MOV DI OFFSET B3 CLD MOV CX. 20 REP MOVSB (3)MOV AX, SEG Bl MOV DS. AX EA SL BI MOV AX SEG B3 LEA DI B3+30 CMP AL.′A′ JB L CMP AL.′Z JA L STOSB L: LOOP M (4) MOV AL,A MOV AX SEG BI MOV ES. AX D,Bl+(20-1) MOV CX. 20 REPNE SCASB JMPL Y LEA BX, [DI-1]的数据个数。 24. (1) MOV AL, ′*′ MOV AX, SEG B3 MOV ES, AX MOV DI, OFFSET B3 CLD MOV CX, 40 REP STOSB (2) MOV AX, SEG B1 MOV DS, AX MOV SI, OFFSET B1 MOV AX, SEG B3 MOV ES, AX MOV DI, OFFSET B3 CLD MOV CX, 20 REP MOVSB (3) MOV AX, SEG B1 MOV DS, AX LEA SI, B1 MOV AX, SEG B3 MOV ES, AX LEA DI, B3+30 CLD MOV CX, 10 M: LODSB CMP AL, ′A′ JB L CMP AL, ′Z′ JA L STOSB L: LOOP M (4) MOV AL, ′A′ MOV AX, SEG B1 MOV ES, AX LEA DI, B1+(20-1) STD MOV CX, 20 REPNE SCASB JE Y MOV BX, -1 JMP L Y: LEA BX, ［DI-1］ 6