我尝试在输入后在nasm
中分割两个数字。这是我的代码 -
%include 'functions.asm'
SECTION .bss
b2: RESB 4
SECTION .text
global _start
_start:
mov edx,4
mov ecx,b2
mov ebx,0
mov eax,3
int 80h
mov eax,35
mov ebx,5
div ebx
call iprintLF
这是我的functions.asm
文件 -
iprint:
push eax ; preserve eax on the stack to be restored after function runs
push ecx ; preserve ecx on the stack to be restored after function runs
push edx ; preserve edx on the stack to be restored after function runs
push esi ; preserve esi on the stack to be restored after function runs
mov ecx, 0
divideLoop:
inc ecx ; count each byte to print - number of characters
mov edx, 0 ; empty edx
mov esi, 10 ; mov 10 into esi
idiv esi ; divide eax by esi
add edx, 48 ; convert edx to it's ascii representation - edx holds the remainder after a divide instruction
push edx ; push edx (string representation of an intger) onto the stack
cmp eax, 0 ; can the integer be divided anymore?
jnz divideLoop ; jump if not zero to the label divideLoop
printLoop:
dec ecx ; count down each byte that we put on the stack
mov eax, esp ; mov the stack pointer into eax for printing
call sprint ; call our string print function
pop eax ; remove last character from the stack to move esp forward
cmp ecx, 0 ; have we printed all bytes we pushed onto the stack?
jnz printLoop ; jump is not zero to the label printLoop
pop esi ; restore esi from the value we pushed onto the stack at the start
pop edx ; restore edx from the value we pushed onto the stack at the start
pop ecx ; restore ecx from the value we pushed onto the stack at the start
pop eax ; restore eax from the value we pushed onto the stack at the start
ret
;------------------------------------------
; void iprintLF(Integer number)
; Integer printing function with linefeed (itoa)
iprintLF:
call iprint ; call our integer printing function
push eax ; push eax onto the stack to preserve it while we use the eax register in this function
mov eax, 0Ah ; move 0Ah into eax - 0Ah is the ascii character for a linefeed
push eax ; push the linefeed onto the stack so we can get the address
mov eax, esp ; move the address of the current stack pointer into eax for sprint
call sprint ; call our sprint function
pop eax ; remove our linefeed character from the stack
pop eax ; restore the original value of eax before our function was called
ret
;------------------------------------------
; int slen(String message)
; String length calculation function
slen:
push ebx
mov ebx, eax
nextchar:
cmp byte [eax], 0
jz finished
inc eax
jmp nextchar
finished:
sub eax, ebx
pop ebx
ret
;------------------------------------------
; void sprint(String message)
; String printing function
sprint:
push edx
push ecx
push ebx
push eax
call slen
mov edx, eax
pop eax
mov ecx, eax
mov ebx, 1
mov eax, 4
int 80h
pop ebx
pop ecx
pop edx
ret
这是我得到的输出 -
分裂后3435973843
。为什么会这样?如果我删除我接受输入的代码部分并且只做div,它就可以了。