1

示例输入输出：

input

34 54

expected output:

54
34

output:

54 54

这是带注释的代码！

#This is a simple "matematical function" program
.section    .rodata #read only data section
str:    .string "Input :\n"

input_format: .string  "%d"
output_format: .string  "%d\n"
.section .bss
input1:  .long
input2:  .long
########
.section  .text     #the beginnig of the code
.globl  main    #the label "main" is used to state the initial point of this program
.type   main, @function # the label "main" representing the beginning of a function
main:   # the main function:

   pushl    %ebp    #save the old frame pointer
   movl %esp,   %ebp    #create the new frame pointer
   #firs number input
   pushl    $input1    # push the ADDRESS of input to have the value stored in it
   pushl    $input_format   # give scanf the ADDRESS of the format string
   call scanf    # call scanf to get number from the user
   addl $8, %esp # clean up the stack
   #second number input
   pushl    $input2    # push the ADDRESS of input to have the value stored in it
   pushl    $input_format   # give scanf the ADDRESS of the format string
   call scanf    # call scanf to get number from the user
   addl $8, %esp # clean up the stack
   # Note the return value of scanf is passed through eax 
   #print the second number
   pushl    input2    # pass the number to printf BY VALUE
   pushl    $output_format  # pass the ADDRESSS of the output format string to printf
   call printf   #call the printf function

   #return from printf:
   movl $0, %eax    #return value is zero (just like in c - we tell the OS that this program finished seccessfully)
   movl %ebp,   %esp    #restore the old stack pointer - release all used memory.

   #print the firs number
   pushl    input1    # pass the number to printf BY VALUE
   pushl    $output_format  # pass the ADDRESSS of the output format string to printf
   call printf   #call the printf function
   #return from printf
   movl $0, %eax    #return value is zero (just like in c - we tell the OS that this program finished seccessfully)
   movl %ebp,   %esp    #restore the old stack pointer - release all used memory
   #end the program
   popl %ebp    #restore old frame pointer (the caller function frame)
   ret  #return to caller function (OS)
4

1 回答 1

0

像这样更改代码：

#This is a simple "matematical function" program
.section    .rodata #read only data section
str:    .string "Input :\n"

input_format: .string  "%d"
output_format: .string  "%d\n"
.section .bss
input1:  .long 24 # CHANGE HERE 
input2:  .long 28 # CHANGE HERE
########
.section  .text     #the beginnig of the code
.globl  main    #the label "main" is used to state the initial point of this program
.type   main, @function
main:   

   pushl    %ebp   
   movl %esp,   %ebp
   andl $-16, %esp # ADD THIS LINE
 ...
 ...
于 2013-07-22T23:52:42.083 回答