将单个十六进制数字转换为十进制数字Intel 8086汇编语言

Question

嗨我在使用此代码时遇到问题。它会打印0-9的罚款，但A-F或A-F只是给我一张笑脸，根据我的教授提供给我们的符号列表，它甚至不是一个ASCII码符号。这是我的代码。请帮忙。我正在使用NASM和DosBox。

org 100h 
; hexadecimal to base 10 conversion program 
section .data 
    MSG1 dw " Enter a hexadecimal digit ", '$' 
    MSG2 dw " In decimal it is: ", '$' 
    MSG3 dw " Do you want to do it again? ", '$' 
    EMSG dw " Illegal character, enter 0..9 or A..F: ", '$' 
section .text 
main: 
; print user prompt 
    mov dx, MSG1 ; get message 
    mov ah, 09h  ; display string function 
    int 21h  ; display it 
    jmp userin  ; jumps to user input so if illegal character is entered message won't display again 
userin: 
; input a hexidecimal number then compare to ASCII codes 
    mov ah, 01h  ; keyboard input function 
    int 21h  ; character input, copies character into al 
    mov bh, al  ; moves al into bh to avoid al being messed with 
    cmp bh, 30h  ; compares input to ASCII code for 0 
     jl error  ; if input is less than 0 jump to main 
    cmp bh, 39h  ; compares input to ASCII code for 9 
    jle print1  ; if input is less than or equal to 9 jump to print 
    cmp bh, 41h  ; compares input to ASCII code for 'A' 
     jl error  ; if input is less than 'A' jump to main 
    cmp bh, 46h  ; compares input to ASCII code for 'F' 
    jle convert1 ; if input is less than or equal to 'F' jump to convert1 
    cmp bh, 61h  ; compares input to ASCII code for 'a' 
     jl error  ; if input is less than 'a' jump to main 
    cmp bh, 66h  ; compares input to ASCII code for 'f' 
    jle convert2 ; if input is less than of equal to 'f' jump to convert2 
     jg error  ; if input is greater than 'z' jump to main 
error: 
; displays error message then jumps back 
    mov dx, EMSG ; moves error message into display string register 
    mov ah, 09h  ; display string function 
    int 21h  ; displays it 
    jmp userin  ; jumps back to user input 
convert1: 
; converts input from hexadecimal A-F to decimal 
    sub bh, 16  ; subtracts 0Fh from input to get decimal 
    jmp print2  ; jumps to print 
convert2: 
; converts input from hexidecimal a-f to decimal 
    sub bh, 48  ; subtracts 30h from the input to get 
    jmp print2  ; jumps to print 
print1: 
; prints the input in decimal form 
    mov dx, MSG2 ; moves MSG2 into display string register 
    mov ah, 09h  ; display string function 
    int 21h  ; display MSG2 "In decimal it is:" 
    mov dl, bh  ; moves input into display character register 
    mov ah, 02h  ; display character function 
    int 21h  ; display input in decimal form 
    jmp again  ; jumps to again 
print2: 
;prints the input in decimal form 
    mov dx, MSG2 ; moves MSG2 into display string register 
    mov ah, 09h  ; display string function 
    int 21h  ; display MSG2 "In decimal it is:" 
    mov dl, 1d  ; will add 10 to the converted ASCII code 
    mov ah, 02h  ; display character function 
    int 21h  ; display 1 in front of input in decimal form 
    mov dl, bh  ; moves converted input to display character register 
    mov ah, 02h  ; display character function 
    int 21h  ; displays converted input 
    jmp again  ; jumps to again 
again: 
; asks if user wants to do it again 
    mov dx, MSG3 ; moves MSG2 into display string register 
    mov ah, 09h  ; display string function 
    int 21h  ; display MSG3 "Do you want to do it again?" 
    mov ah, 01h  ; keyboard input function 
    int 21h  ; character input, copies into al 
    cmp al, 59h  ; compares input to ASCII code for 'Y' 
     je main  ; if input is equal to 'Y' jump to main 
     jl exit  ; if input is less than 'Y' jump to exit 
    cmp al, 79h  ; compares input to ASCII code for 'y' 
     je main  ; if input is equal to 'y' jump to main 
    jne exit  ; if input is not equal to 'y' jump to exit 
exit: 
;exit to DOS 
     mov  ah, 04Ch  ; DOS function: Exit program 
     mov  al, 0   ; Return exit code value 
     int  21h   ; Call DOS. Terminate program 

Answer 1

计算是正确的，但应打印领先“1”的代码是错误的。您需要将字符代码放在DL中，而不是数字。因此，而不是

mov dl, 1d  ; will add 10 to the converted ASCII code 
mov ah, 02h  ; display character function 
int 21h  ; display 1 in front of input in decimal form 

应该

mov dl, 49  ; will add 10 to the converted ASCII code 
mov ah, 02h  ; display character function 
int 21h  ; display 1 in front of input in decimal form