小弟初学，怎样在屏幕上显示这个-51 ?

[163lzm]

请问一个变量 abc = -51
怎样在屏幕上显示这个-51

[163lzm]

正的我会，就差负的

[dunkel]

有符号数实际上也很简单啊. 先判断是否为负数, 是的话, 先置负数符号('-'), 再将原数值取反(neg ??), 接下来就和正数及无符号数一样了.

[163lzm]

谢谢楼上的热心回答，我就是这么试的，（先判断是否为负数, 是的话, 先置负数符号('-'), 再将原数值取反(neg ??), 接下来就和正数及无符号数一样）处理，但我试过无论输入什么负数，它都只输出-E1啊？
继续求助。

[dunkel]

输入正数正常吗? 如果正常的话, 可以在 neg ?? 指令上设个断点检查一下.

[csdsjkk]

代码贴上来

[ahjoe]

;正数输出，负数请自己修改
.286
public outnum
code segment
assume cs:code, ds:code

count1 db 0
count2 db 0
endchar db 0
maxdigit db 0
db 0
dw 0
value dw 0
dw 0
outnum proc far
; IN:
; LONG IN DX:AX, WORD IN AX
; BL(b1_b0)=1 WORD
; 2 LONG
; BL(b3_b2)=0 BIN
; 1 DEC
; 2 HEX
; BL(b4)=1 HAS SIGN
; 0 HAS NOT SIGN
; BL(b5)=1 HAS BDHID
; 0 HAS NOT BDHID
; BH=DIGIT AMOUNT LIMIT

push ax
push bx
push cx
push dx
push ds
mov cx, cs
mov ds, cx
db 66h
xor cx, cx
db 66h
mov value, cx
db 66h
mov word ptr maxdigit, cx
mov value, ax
mov count1, bh
mov count2, bh

test bl, 10h
jz nosign

test bl, 1
jnz wordsign
longsign:
test dh, 80h
jz plusid
lminusid: not ax
not dx
inc ax
adc dx, 0
jmp totmin
wordsign:
test ah, 80h
jz plusid
wminusid:
neg ax
totmin:
mov cl, '-'
jmp totsid
plusid:
mov cl, '+'
totsid:
call outchar

nosign:
mov value+2, dx
test bl, 2
jnz outlong
mov value+2, 0
outlong:
db 66h
mov ax, value
db 66h
xor dx, dx
test bl, 0ch
jz bini
test bl, 04h
jnz deci
hexi:
mov maxdigit, 16
mov endchar, 'H'
jmp totdig
deci:
mov maxdigit, 10
mov endchar, 'D'
jmp totdig
bini:
mov maxdigit, 2
mov endchar, 'B'
totdig:
xor dx, dx
db 66h
div word ptr maxdigit
push dx
dec count1
jnz totdig
divend:
pop cx
or cl, 30h
cmp cl, '9'
jbe digit10
add cl, 7
digit10:
call outchar
dec count2
jnz divend

test bl, 20h
jz nobdh
mov cl, endchar
call outchar
nobdh:
pop ds
pop dx
pop cx
pop bx
pop ax
retf
outnum endp

outchar proc near
xchg ax, cx
mov ah, 0eh
int 10h
xchg ax, cx
retn
outchar endp

code ends
end outnum

[163lzm]

up

[dunkel]

要先将数值转换为显示的字符串, 再显示字符串才可以. 可以看看这个帖子:

http://expert.csdn.net/Expert/topic/2348/2348789.xml?temp=.1283686

(给出的代码是倒序存放的, 并且没有考虑符号数, 不过还是有参考价值)

[163lzm]

谢谢各位,代码贴出来，
谁答得好给100分，谢谢，真想搞明白它啊！！！

正数是没问题的
DATA SEGMENT
; BUF DB 12,87,51,68,0,15 ;-51 ?? how to display
BUF DB 12,87,-51,68,0,15 ;-51 ?? how to display
N EQU $-BUF
S_END DB 0AH,0DH,'$'
DATA ENDS

CODE SEGMENT
ASSUME CS:CODE,DS:DATA
START: MOV AX,DATA
MOV DS,AX

CALL SHOWQ


MOV DX,N-1

LOP1: MOV SI,OFFSET BUF
MOV CX,N-1
LOP2: MOV AL,[SI]
CMP AL,[SI+1] ;al<=[si+1]
JLE LOP3
XCHG AL,[SI+1]
MOV [SI],AL
LOP3: INC SI
DEC CX
JNZ LOP2
DEC DX
JNZ LOP1

;CALL SHOWQ

MOV AH,4CH
INT 21H


SHOWQ PROC
MOV SI,OFFSET BUF
MOV BX,N
;LOP0:
; MOV AL,[SI]
; CMP AL,0
; JL SHOWNEG
; JMP SHOWNEG
SHOWNUM:
MOV AH,0
MOV CL,10
DIV CL
;IDIV CL
ADD AL,30H
MOV DH,AH
MOV DL,AL
MOV AH,02H
INT 21H
ADD DH,30H
MOV DL,DH
MOV AH,02H
INT 21H

MOV DL,' '
MOV AH,02H
INT 21H

INC SI
DEC BX
JNZ LOP0
;MOV DL,0AH
;MOV AH,02H
;INT 21H
;MOV DL,0DH
;MOV AH,02H
;INT 21H
MOV AX,OFFSET S_END
MOV DX,AX
MOV AH,09
INT 21H

RET

SHOWNEG:MOV DL,'-'
MOV AH,02
INT 21H
MOV DL,AL
;MOV AL,0
;SUB AL,DL

;MOV AL,DL
NEG AL
JMP SHOWNUM

SHOWQ ENDP
CODE ENDS
END START

[csdsjkk]

DATA SEGMENT
; BUF DB 12,87,51,68,0,15 ;-51 ?? how to display
BUF DB 12,87,-51,68,0,15 ;-51 ?? how to display
N EQU $-BUF
S_END DB 0AH,0DH,'$'
DATA ENDS

CODE SEGMENT
ASSUME CS:CODE,DS:DATA
START: MOV AX,DATA
MOV DS,AX

CALL SHOWQ


MOV DX,N-1

LOP1: MOV SI,OFFSET BUF
MOV CX,N-1
LOP2: MOV AL,[SI]
CMP AL,[SI+1] ;al<=[si+1]
JLE LOP3
XCHG AL,[SI+1]
MOV [SI],AL
LOP3: INC SI
DEC CX
JNZ LOP2
DEC DX
JNZ LOP1

;CALL SHOWQ

MOV AH,4CH
INT 21H


SHOWQ PROC
MOV SI,OFFSET BUF
MOV BX,N
LOP0:
MOV AL,[SI]
CMP AL,0
JL SHOWNEG
; JMP SHOWNEG
SHOWNUM:
MOV AH,0
MOV CL,10
DIV CL
;IDIV CL
ADD AL,30H
MOV DH,AH
MOV DL,AL
MOV AH,02H
INT 21H
ADD DH,30H
MOV DL,DH
MOV AH,02H
INT 21H

MOV DL,' '
MOV AH,02H
INT 21H

INC SI
DEC BX
JNZ LOP0
;MOV DL,0AH
;MOV AH,02H
;INT 21H
;MOV DL,0DH
;MOV AH,02H
;INT 21H
MOV AX,OFFSET S_END
MOV DX,AX
MOV AH,09
INT 21H

RET

SHOWNEG:MOV DL,'-'
MOV AH,02
push ax
INT 21H
pop ax
MOV DL,AL
;MOV AL,0
;SUB AL,DL

;MOV AL,DL
NEG AL
JMP SHOWNUM

SHOWQ ENDP
CODE ENDS
END START

[163lzm]

一个字，谢！！！

[163lzm]

怎样才可给超过原定的分啊，csdsjkk兄？