基本上，这是一个用Assembly编写的Factorial程序。
TITLE factor.asm
.model small
.stack
.data
msg1 db 0Dh,0Ah, 'enter the number: $'
msg2 db 0Dh,0Ah, 'factorial: $'
msg3 db 0Dh,0Ah, 'the result is too big!', 0Dh,0Ah, 'use values from 0 to 8. $'
.code
org 100h
start1:
mov ax,@data
mov ds,ax
mov ax, 0
putc macro char
push ax
mov al, char
mov ah, 0eh
int 10h
pop ax
endm
jmp start
result dw ?
start:
; get first number
mov ah, 9
mov dx, offset msg1
int 21h
jmp n1
n1:
call scan_num
; compute factorial of 0 = 1:
mov ax, 1
cmp cx, 0
je print_result
mov bx, cx
mov ax, 1
mov bx, 1
calculate:
mul bx
cmp dx, 0
jne overflow
inc bx
loop calculate
mov result, ax
print_result:
; put result in ax:
mov dx, offset msg2
mov ah, 9
int 21h
jmp n2
n2:
mov ax, result
call print_num_uns
jmp exit
overflow:
mov dx, offset msg3
mov ah, 9
int 21h
jmp n3
n3:
jmp start
exit:
; wait for any key press:
mov ah, 0
int 16h
ret
SCAN_NUM PROC NEAR
PUSH DX
PUSH AX
PUSH SI
MOV CX, 0
MOV CS:make_minus, 0
next_digit:
MOV AH, 00h
INT 16h
MOV AH, 0Eh
INT 10h
CMP AL, '-'
JE set_minus
CMP AL, 0Dh
JNE not_cr
JMP stop_input
not_cr:
CMP AL, 8
JNE backspace_checked
MOV DX, 0
MOV AX, CX
DIV CS:ten
MOV CX, AX
PUTC ' '
PUTC 8
JMP next_digit
backspace_checked:
CMP AL, '0'
JAE ok_AE_0
JMP remove_not_digit
ok_AE_0:
CMP AL, '9'
JBE ok_digit
remove_not_digit:
PUTC 8
PUTC ' '
PUTC 8
JMP next_digit
ok_digit:
PUSH AX
MOV AX, CX
MUL CS:ten
MOV CX, AX
POP AX
CMP DX, 0
JNE too_big
SUB AL, 30h
MOV AH, 0
MOV DX, CX
ADD CX, AX
JC too_big2
JMP next_digit
set_minus:
MOV CS:make_minus, 1
JMP next_digit
too_big2:
MOV CX, DX
MOV DX, 0
too_big:
MOV AX, CX
DIV CS:ten
MOV CX, AX
PUTC 8
PUTC ' '
PUTC 8
JMP next_digit
stop_input:
CMP CS:make_minus, 0
JE not_minus
NEG CX
not_minus:
POP SI
POP AX
POP DX
RET
make_minus DB ?
SCAN_NUM ENDP
PRINT_NUM PROC NEAR
PUSH DX
PUSH AX
CMP AX, 0
JNZ not_zero
PUTC '0'
JMP printed
not_zero:
CMP AX, 0
JNS positive
NEG AX
PUTC '-'
positive:
CALL PRINT_NUM_UNS
printed:
POP AX
POP DX
RET
PRINT_NUM ENDP
PRINT_NUM_UNS PROC NEAR
PUSH AX
PUSH BX
PUSH CX
PUSH DX
MOV CX, 1
MOV BX, 10000
CMP AX, 0
JZ print_zero
begin_print:
CMP BX,0
JZ end_print
CMP CX, 0
JE calc
CMP AX, BX
JB skip
calc:
MOV CX, 0
MOV DX, 0
DIV BX
ADD AL, 30h
PUTC AL
MOV AX, DX
skip:
PUSH AX
MOV DX, 0
MOV AX, BX
DIV CS:ten
MOV BX, AX
POP AX
JMP begin_print
print_zero:
PUTC '0'
end_print:
POP DX
POP CX
POP BX
POP AX
RET
PRINT_NUM_UNS ENDP
ten DW 10
int 27h
end start1
This is a sample screenshot of the program above
8！ = 40,320 = 1001 1101 1000 0000
9！ = 362,880 = 0101 1000 1001 1000 0000
我的问题是我希望我的程序允许计算0到15的阶乘。
可能的解决方案：
更改了它，但错误显示“操作数类型不匹配”，所以我;
发生错误，“转发参考需要覆盖”
Line 120 : DIV CS:ten
Line 144 : MUL CS:ten
Line 169 : DIV CS:ten
Line 254 : DIV CS:ten
它甚至意味着什么？