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我有一段时间做作业，很喜欢一些指导。该任务要求您将任何基数的ASCII字符串转换为任意基数。当我调用AsciiToDigit过程（嵌套在ReadInteger过程中）时，程序挂起，我找不到原因。调试器没有任何帮助，因为它不会执行任何操作，而只会在程序的该部分挂起。x86将ASCII字符转换为数字
我相当肯定我需要将字符转换为数字先做正确的，但也许我失去了一些东西。感谢任何人都可以提供的帮助。
TITLE MASM Template (main.asm)
; Description:
;
; Revision date:
INCLUDE Irvine32.inc
.data
basePrompt BYTE "What base (2-16 or 0 to quit): ",0
numPrompt BYTE "Number please: ",0
invalid BYTE "Invalid base, please try again.",0
base2 BYTE "Base 2: ",0
base8 BYTE "Base 8: ",0
base10 BYTE "Base 10: ",0
base16 BYTE "Base 16: ",0
base DWORD 0
.code
main PROC
call Clrscr
State0: ; initial state to accept base number
mov edx, OFFSET basePrompt
call ReadBase
cmp al, '0' ; check if 0 entered
je ProgEnd ; jump to ProgEnd if 0 entered
mov base, ebx
mov edx, OFFSET numPrompt
call WriteString
call ReadInteger
mov ebx, 2
mov edx, OFFSET base2
call WriteString
call WriteInteger
mov ebx, 8
mov edx, OFFSET base8
call WriteString
call WriteInteger
mov ebx, 10
mov edx, OFFSET base10
call WriteString
call WriteInteger
mov ebx, 16
mov edx, OFFSET base16
call WriteString
call WriteInteger
call Crlf
jmp State0 ; jump back to beginning of program
ProgEnd: ; jump point to end of programt
exit
main ENDP
;-----------------------------------------------------
ReadInteger PROC
;
; ReadInteger is passed one argument in bl representing the base of the number to be input.
; Receives: bl register
; Returns: EAX
;-----------------------------------------------------
nextChar:
call ReadChar ; Get the next keypress
call WriteChar ; repeat keypress
call AsciiToDigit
shl ebx,1 ; shift to make room for new bit
or ebx,eax ; set the bit to eax
cmp al, 13 ; check for enter key
jne nextChar
ret
ReadInteger ENDP
;-----------------------------------------------------
WriteInteger PROC
;
; Will display a value in a specified base
; Receives: EAX register (integer), bl (base)
; Returns: nothing
;-----------------------------------------------------
mov ecx, 0 ;count the digits
nextDigit:
mov edx, 0 ;prepare unsigned for divide
div ebx
push edx ;remainder will be in dl
inc ecx ;count it!
cmp eax,0 ;done when eax becomes 0
jne nextDigit
;now the digits are on the stack
;pop them off and convert to ASCII for output
outDigit:
pop eax ;digits come off left to right
add eax, '30' ;add 0011 to front to get ASCII
call WriteChar
loop outDigit
call Crlf
ret
ret
WriteInteger ENDP
;-----------------------------------------------------
ReadBase PROC
;
; Prompts the user for input and stores input into EAX.
; Receives: EDX register
; Returns: EAX
;-----------------------------------------------------
Call WriteString
xor ebx, ebx ; clear ebx
call ReadChar
call WriteChar
cmp al, '0'
je Done
cmp al, 13 ; look for return carriage, jump to end
je Done
mov ebx, eax
shl ebx, 1 ; shift ebx left one
call ReadChar
call WriteChar
or ebx, eax
Done:
call Crlf
ret
ReadBase ENDP
;-----------------------------------------------------
AsciiToDigit PROC
;
; This procedure receives the ASCII code of a digit and returns the numerical digit value.
; Receives: EAX register
; Returns: EAX
;-----------------------------------------------------
cmp eax, 61h
jb Upper
sub eax,61h
jmp done
Upper:
cmp eax, 41h
jb Digit
sub eax, 41h
jmp done
Digit:
sub eax,30h
done:
ret
AsciiToDigit ENDP
;-----------------------------------------------------
DigitToAscii PROC
;
; This procedure receives digit and returns Ascii value
; Receives: EAX register
; Returns: EAX
;-----------------------------------------------------
add eax, 30h
ret
DigitToAscii ENDP
END main
将'add eax，30h'改为'add eax'，'0''会改善代码的可读性。另外，也许'add eax'，'30'应该是'add eax'，'0''。 – AusCBloke 2012-02-25 03:05:21
谢谢你非常好。尽管如此。 – 2012-02-25 03:14:34
ReadChar是否将结果返回给EAX？ WriteChar保存EAX吗？ AsciiToDigit显然期望EAX中的结果，因此请检查该假设。如果你的调试器没有帮助，删除线路直到它工作。删除WriteChar。将ReadChar替换为EAX的简单赋值（假设您调用该函数并获得了很好的输入）。跳过对AsciiToDigit的呼叫。修剪你的程序，直到它工作。此外，你应该记录“为什么”，而不是“什么”。像“shift ebx left one”这样的评论是无用的，因为它清楚'shl ebx，1'的作用。但是*为什么*你将ebx左移1？ – indiv 2012-02-25 05:17:39