在程序集8086中将字符串十进制覆盖为二进制和十六进制 [英] Coverting String Decimal to Binary and Hexa in Assembly 8086

问题描述

我正在尝试将使用此代码读取的字符串转换为二进制和六进制.

I'm trying to convert a string I read with this code to binary and hexa.

READ_STRING:
    MOV DX, offset buffer
    MOV AH, 0Ah
    INT 21h
    MOV SI, 1d
    MOV AX, 0
    XOR CX, CX
    MOV CL, buffer[SI]
    INC SI

LOOP_1:
    MOV DX, 10
    MUL DX
    MOV DL, buffer[SI]
    SUB DL, 30h
    MOV DH, 0
    ADD AX, DX
    INC SI
    LOOP LOOP_1

    RET

到目前为止，我已经将此代码用于二进制输出，但是它始终显示"1001"(十进制为9):

So far I have this code for binary output but it always prints "1001" (9 in decimal):

NEXT:

    XOR AX, AX
    XOR BX, BX
    XOR CX, CX
    MOV CL, 2
    MOV AL, byte ptr[nombre]
    MOV DI, offset binaire

; DIV : divide AX by CL. Remainder in AH and result in AL

LOOP:
    DIV CL ; remainder in AH, quotient in AL
    ADD AH, '0' ;  0 -> '0' , 1 -> '1'
    MOV [DI], AH ; Saves the remainder in the array
    INC DI
    MOV AH, 0 ; reset AH for next division
    CMP AL, 0 ; if result is 0, end
    JNE LOOP

;Prints the binary number               
    MOV DX, offset binaire
    CALL WRITE_STRING

谢谢！如果您还需要其他任何内容，请问.

Thanks! If you need anything else just ask.

推荐答案

在担心是否可以将值显示为二进制或十六进制之前；请检查以确保您的代码正确地将用户的输入转换为整数(例如，使用调试器).

Before worrying about whether or not you can display the value as binary or hexadecimal; check to make sure your code correctly converts the user's input into an integer (e.g. with a debugger).

对于二进制文件，请考虑以下内容:

For binary, consider something like this:

    mov bx,ax              ;bx = the value to display as binary
    mov cx,16              ;cx = number of bits to display
    mov di,offset binaire  ;es:di = address to store string

.nextBit:
    xor ax,ax              ;al = 0
    add bx,bx              ;bx = value * 2; carry flag = overflow
    adc al,0               ;al = '0' or '1'
    stosb                  ;Add new character to string
    loop .nextBit
    mov byte [di],0        ;Terminate the string (ASCIIZ?)

    mov dx, offset binaire
    call WRITE_STRING

对于十六进制，这是相同的基本概念，不同之处在于，您需要提取最高的4位:

For hexadecimal, it's the same basic idea, except you need to extract the highest 4 bits:

    mov bx,ax              ;bx = the value to display as binary
    mov cx,4               ;cx = number of nibbles to display
    mov di,offset binaire  ;es:di = address to store string

.nextNibble:
    mov ax,bx              ;ax = value
    shr ax,12              ;ax = highest 4 bits of value
    shl bx,4               ;bx = value << 4
    add al,'0'
    cmp al,'9'
    jbe .gotChar
    add al,'A' - '9'
.gotChar:
    stosb                  ;Add new character to string
    loop .nextBit
    mov byte [di],0        ;Terminate the string (ASCIIZ?)

    mov dx, offset binaire
    call WRITE_STRING

注1:我没有测试过上面的任何代码，并且我通常使用NASM(而不是MASM)，因此它可能不会按原样"汇编.

Note 1: I haven't tested any of the code above, and I normally use NASM (not MASM), so it may not assemble "as is".

注2:上面的示例代码特意简单.为了提高性能，您可以使用查找表来做得更好.

Note 2: Example code above is intentionally simple. For performance you could do a lot better using lookup tables instead.

注3:这些不是复杂的算法，您不必首先弄乱高级语言(除非您可能不了解二进制/十六进制转换的原理/数学).同样，一种语言看起来很优雅的算法在另一种语言上可能很丑陋(例如，您无法在C语言中以简单/简洁的方式检测到溢出，因此上面用于二进制转换的方法既不明显也不优雅)在C中；而在C中优雅的另一种方法可能会在汇编中带来严重的问题.

Note 3: These aren't complex algorithms and you shouldn't need to mess about with high level languages first (unless you don't understand the theory/maths behind binary/hex conversion perhaps). Also, an algorithm that seems elegant in one language can be an ugly mess in another language (e.g. you can't detect overflow in an easy/clean way in C, so the method used for binary conversion above wouldn't be obvious or elegant in C; and a different method that is elegant in C might suck badly in assembly).

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