给出以下代码:
.globl main
.type main, @function
input: .string "%d"
main:
pushl %ebp # save the old frame pointer
movl %esp,%ebp # create the new frame pointer
movl $0,%eax
addl $-4 ,%esp # moving down the stack
pushl %esp # push the address of esp to the stack in order to store the number given by the user
pushl $input # push to the stack the format of the input
call scanf # call scanf to get a number from the user
addl $8,%esp # clear the stack
movl (%esp),%eax # get the selection from the user
subl $50,%eax
jmp *.switching(,%eax,4)
.section .rodata
.align 4
.switching:
.long .L1
.long .L2
.long .L3
.long .L4
.text
.L1:
call case1
jmp .quitTheProgram
.L2:
call case2
jmp .quitTheProgram
.L3:
call case
jmp .quitTheProgram
.L4:
call case4
jmp .quitTheProgram
case1:
pushl %ebp # save the old frame pointer
movl %esp,%ebp # create the new frame pointer
#
# code of case1
#
movl %ebp,%esp # restore the old ebp
popl %ebp # restore the old stack pointer and release all used memory
ret # return to caller function (OS)
用户按下50-54之间的数字。问题是在按下(例如)50之后
我跳转到case1,但不是代码本身,而是直接到ret
行,然后代码停止并退出case1
(就其他情况而言)。
可能是什么问题?
的问候,罗恩
答案 0 :(得分:0)
问题是按下后(例如)50我跳转到case1,但不是代码本身,而是直接到ret行
我刚刚在Linux上构建了你的代码,在GDB中逐步完成了代码,并且没有观察到了这种行为。
你有可能错误地解释了你实际观察到的内容。