微机原理：顺序、分支、循环、子程序设计

INT 21H CODEM ENDS

CODES SEGMENT

ASSUME CS:CODES ;the part of subprogram BCD-16B PROC FAR PUSH BX PUSH AX ADD SI, CX MOV DX, 0 BCDL:

DEC SI PUSH CX MOV AL, [SI] AND AL, 0FH CBW

MOV BX, AX MOV AX, DX MOV CX, 10 MUL CX

MOV DX, AX ADD DX, BX POP CX LOOP BCDL POP AX POP BX RET

BCD-16B ENDP CODES ENDS END START

②使用储存器传递参数

name \STACK SEGMENT STACK DB 256 DUP(?) STACK ENDS

DATA SEGMENT

BCD1 DB 07H, 06H, 07H, 02H, 03H ADSEG DW ? ADOFST DW ? LENG1 DW ? RESULT DW ?

DATA ENDS

CODEM SEGMENT

ASSUME CS:CODEM, DS:DATA, SS:STACK START:

MOV AX, DATA MOV DS, AX

;entrance parameter MOV AX, SEG BCD1 MOV ADSEG, AX

MOV AX, OFFSET BCD1 MOV ADOFST, AX MOV LENG1, 5

CALL FAR PTR BCD-16B MOV AH, 4CH INT 21H CODEM ENDS

CODES SEGMENT

ASSUME CS:CODES ;the part of subprogram BCD-16B PROC FAR PUSH BX PUSH AX PUSH SI PUSH DS

MOV DS, ADSEG MOV SI, ADOFST MOV CX, LENG1 XOR DX, DX ADD SI, CX BCDL:

DEC SI PUSH CX MOV AL, [SI] AND AL, 0FH CBW

MOV BX, AX MOV AX, DX MOV CX, 10 MUL CX

MOV DX, AX ADD DX, BX

POP CX LOOP BCDL POP AX POP BX POP DS POP SI RET

BCD-16B ENDP CODES ENDS END START

③使用堆栈传递参数

name \STACK SEGMENT STACK DB 256 DUP(?) STACK ENDS

DATA SEGMENT

BCD1 DB 07H, 06H, 07H, 02H, 03H LENG1 DW ? RESULT DW ? DATA ENDS

CODEM SEGMENT

ASSUME CS:CODEM, DS:DATA, SS:STACK START:

MOV AX, DATA MOV DS, AX ;push PUSH DS LEA SI, BCD1 PUSH SI

MOV CX, LENG1 PUSH CX

CALL FAR PTR BCD-16B POP DX

MOV RESULT, DX MOV AH, 4CH INT 21H CODEM ENDS

CODES SEGMENT

ASSUME CS:CODES

;the part of subprogram BCD-16B PROC FAR PUSH BP MOV BP, SP PUSH DS PUSH SI PUSH CX PUSH BX PUSH AX

MOV CX, [BP]+6 MOV SI, [BP]+8 MOV DS, [BP]+10 ADD SI, CX MOV DX, 0 BCDL:

DEC SI PUSH CX MOV AL, [SI] AND AL, 0FH CBW

MOV BX, AX MOV AX, DX MOV CX, 10 MUL CX

MOV DX, AX ADD DX, BX POP CX LOOP BCDL POP AX POP BX POP CX POP DS POP SI POP BP RET A BCD-16B ENDP CODES ENDS END START