Assembly 32位英特尔汇编比较和跳转
这看起来应该行得通,但在输入值之后,我一直会遇到分段错误。有什么建议吗Assembly 32位英特尔汇编比较和跳转,assembly,intel,32-bit,Assembly,Intel,32 Bit,这看起来应该行得通,但在输入值之后,我一直会遇到分段错误。有什么建议吗 .section .data speed: .int 0 fine: .int 0 points: .int 0 inputPrompt: .asciz "Enter an integer value for speed ==> " outputPrompt: .asciz "With a speed of %d the fine will be $%d and %d points will be added to
.section .data
speed: .int 0
fine: .int 0
points: .int 0
inputPrompt: .asciz "Enter an integer value for speed ==> "
outputPrompt: .asciz "With a speed of %d the fine will be $%d and %d points will be added to your license"
inputSpec: .ascii "%d"
.section .text #read in values
.globl main
main:
nop
pushl $inputPrompt
call printf
addl $4, %esp
#read in speed value
pushl $speed
pushl $inputSpec
call scanf
addl $8, %esp
#-------------------greater than or equal to 86--------------------------
movl speed, %eax
subl $85, %eax
Jg fine4
#-------------------81 - 85---------------------------------------------
movl speed, %eax
subl $80, %eax
Jg fine3
#-------------------76 - 80---------------------------------------------
movl speed, %eax
subl $75, %eax
Jg fine2
#-------------------71 - 75---------------------------------------------
movl speed, %eax
subl $70, %eax
Jg fine1
#-----------------less than 71-----------------------------------------------
movl $0, fine
movl $0, points
JMP output
#---------------------71 - 75-------------------------------------------
fine1:
movl $60, fine
movl $2, points
JMP output
#---------------------76 - 80-------------------------------------------
fine2:
movl $90, fine
movl $3, points
JMP output
#---------------------81 - 85-------------------------------------------
fine3:
movl $120, fine
movl $4, points
JMP output
#---------------------less than or equal to 86------------------------------------------
fine4:
movl $150, fine
movl $6, points
#----------------------------------------------------------------
output:
pushl points
pushl fine
pushl speed
pushl outputPrompt
call printf
addl $8, %esp
#-----------------------------------------------------------------
call exit
您缺少一个
$
登录pushl outputPrompt
。该指令将outputPrompt
的前4个字节放在堆栈上,但您需要地址。因此,请使用pushl$outputPrompt
此外,还要学习使用调试器,以便您可以修复自己的错误。inputSpec是.ascii而不是.asciz有什么原因吗?scanf预计这将以null结尾,这可能是seg故障的原因。在调用scanf期间是否发生崩溃?如果没有,具体是在哪个指令上。如果是,那么它可能来自未对齐的堆栈,或者来自James提到的缺少nul终止。我将inputSpec更改为.asciz,并且我仍然在相同的位置遇到分段错误。我在终端中运行它,所以它不会告诉我错误来自何处,我将
pushl speed pushl testPrompt\#-->testPrompt:.asciz“值为%d”在扫描后调用printf addl$8,%esp
来测试它是否超过了该点,并且它在没有新输出的情况下保持分段错误。您使用的汇编程序是什么?您是如何运行代码的?有一条cmp
指令,它将省去您在sub
之后重新加载原始代码的麻烦。它设置与sub
相同的标志,但不写入目标寄存器。由于间隔都是相同的,您还可以检查>71,然后将该数字映射到查找表索引(减去71除以5,然后钳制最大索引)