简介
输入一个16进制数，使用堆栈传参的方式实现阶乘的计算并以16进制输出结果
程序运行结果
3的阶乘
5的阶乘
6的阶乘
7的阶乘
n=3时栈的情况
debug截图
分析
代码
ASSUME CS:CODE1,DS:DATA1,SS:STACK1
STACK1 SEGMENT STACK
STACK_AREA DW 200H DUP(?)
STACK_BTM EQU $-STACK_AREA
STACK1 ENDS
DATA1 SEGMENT
RESULT DW 1
DATA1 ENDS
CODE1 SEGMENT
FACT PROC NEAR ; [SP+2] return address [SP+4] n
PUSH BP
MOV BP,SP
PUSH CX
PUSH AX
PUSH BX
MOV BX,[BP+4]
MOV AX,[BP+6]
CMP AX,1
JE FACT_EXIT
SUB AX,1
PUSH AX
PUSH BX
CALL FACT
MOV AX,[BX]
MOV CX,[BP+6]
MUL CX
MOV [BX],AX
FACT_EXIT:
POP BX
POP AX
POP CX
POP BP
RET 4
FACT ENDP
MAIN PROC FAR
MOV AX,STACK1
MOV SS,AX
MOV SP,STACK_BTM
MOV AX,DATA1
MOV DS,AX
MOV ES,AX
MOV BX,0
READHEX_LOOP:
MOV AH,01
INT 21H
CMP AL,'0'
JB READHEX_LOOP_END
CMP AL,'9'
JA READHEX_ASCII
SUB AL,'0'
JMP READHEX_READ
READHEX_ASCII:
OR AL,32
CMP AL,'a'
JB READHEX_LOOP_END
CMP AL,'f'
JA READHEX_LOOP_END
SUB AL,'a'-10
READHEX_READ:
SHL BX,1
SHL BX,1
SHL BX,1
SHL BX,1
MOV AH,0
ADD BX,AX
JMP READHEX_LOOP
READHEX_LOOP_END:
PUSH BX
MOV BX,OFFSET RESULT
PUSH BX
CALL FACT
MOV CX,4
MOV AX,RESULT
OUTPUT16_LOOP:
ROL AX,1
ROL AX,1
ROL AX,1
ROL AX,1
MOV DL,AL
AND DL,15
CMP DL,10
JAE OUTPUT_ASCII
ADD DL,'0'
JMP OUTPUT_NEXT
OUTPUT_ASCII:
ADD DL,'A'-10
OUTPUT_NEXT:
PUSH AX
MOV AH,02H
INT 21H
POP AX
LOOP OUTPUT16_LOOP
MOV AX,4C00H
INT 21H
MAIN ENDP
CODE1 ENDS
END MAIN
