Code1: implements main function which calls fact (factorial) function
Code1:实现调用fact(factorial)函数的main函数
section .data
msg db "Enter the Number whose factorial is to be calculated",10,0
msg1 db "The factorial is: ",0
ioput db "%d"
section .bss
a resd 1
section .text
global main
extern printf,scanf,fact
main:
pusha
push msg
call printf
add esp,4
popa
pusha
push a
push ioput
call scanf
add esp,8
popa
mov ebx,dword[a]
pusha
push ebx
call fact
add esp,4
pusha
push msg1
call printf
add esp,4
popa
pusha
push eax
push ioput
call printf
add esp,8
popa
ret
Code2 which implements fact (factorial function):
实现事实的Code2(阶乘函数):
section .text
global fact
extern printf,scanf
fact:
enter 0,0
cmp ebx,1
jnz next
ret
next:
push ebx
dec ebx
call fact
pop ebx
mul eax,ebx
leave
ret
System stats: 32 bit machine, Ubuntu 14.04, Nasm is used
系统统计:32位机器,Ubuntu 14.04,使用Nasm
Problem statement: Program received signal SIGILL, Illegal instruction. Why am I getting this error?
问题陈述:程序接收信号SIGILL,非法指令。为什么我收到此错误?
1 个解决方案
#1
mov ebx,dword[a]
pusha
push ebx
call fact
add esp,4
This is the part of your program that has some problems!
这是你的程序中有一些问题的一部分!
- You need to initialize EAX to get meaningful results from calling fact. A convenient number would be 1.
- Since you used
pushayou also need to usepopa. I would have preferred none because your code doesn't really need it. - The fact routine doesn't use a parameter passed on the stack. It simply uses the EBX register for that purpose. This means that you can omit
push ebxandadd esp,4and also that you could remove theenterandleaveinstructions from fact.
您需要初始化EAX以从调用fact获得有意义的结果。一个方便的数字是1。
既然你使用了pusha,你还需要使用popa。我宁愿没有,因为你的代码并不真正需要它。
事实例程不使用在堆栈上传递的参数。它只是为此目的使用EBX寄存器。这意味着您可以省略push ebx并添加esp,4以及您可以从事实中删除enter和leave指令。
This is the code you could write to solve it all.
这是您可以编写的代码来解决所有问题。
mov ebx,dword[a]
mov eax,1
pusha
call fact
mov [esp+28],eax
popa
A shorter version is
更短的版本是
mov ebx,dword[a]
mov eax,1
call fact
#1
mov ebx,dword[a]
pusha
push ebx
call fact
add esp,4
This is the part of your program that has some problems!
这是你的程序中有一些问题的一部分!
- You need to initialize EAX to get meaningful results from calling fact. A convenient number would be 1.
- Since you used
pushayou also need to usepopa. I would have preferred none because your code doesn't really need it. - The fact routine doesn't use a parameter passed on the stack. It simply uses the EBX register for that purpose. This means that you can omit
push ebxandadd esp,4and also that you could remove theenterandleaveinstructions from fact.
您需要初始化EAX以从调用fact获得有意义的结果。一个方便的数字是1。
既然你使用了pusha,你还需要使用popa。我宁愿没有,因为你的代码并不真正需要它。
事实例程不使用在堆栈上传递的参数。它只是为此目的使用EBX寄存器。这意味着您可以省略push ebx并添加esp,4以及您可以从事实中删除enter和leave指令。
This is the code you could write to solve it all.
这是您可以编写的代码来解决所有问题。
mov ebx,dword[a]
mov eax,1
pusha
call fact
mov [esp+28],eax
popa
A shorter version is
更短的版本是
mov ebx,dword[a]
mov eax,1
call fact