应用的方法：编写一个子函数---max，对于每组数据分别调用max子函数，求出三个数值，在选出三个数中的最大者。
但是，编译，链接过程都没有报错，运行时一直出现“段错误139”，
用gdb时显示为：子函数中的“movl (%ebx),%ecx“ 和 ”movl (%ebx,%edi,4),%eax“ 出现段错误，
求助问题的解决方法。
代码： 全选
#PURPOSE: Find the maximum number in these three data items,
# for every item we will call MAX to find the maximum one
# in THIS item.
#
#VARIABLE: %edx - Holds the MAXIMUM data of the three items.
#
#The following memory locations are used:
#
#data_itemN - contains the item data.
#
#
.section .data
data_item1:
.long 3,67,34,222,45,75,1,34,44,33,22,11,66,4
data_item2:
.long 98,23,43,54,23,67,8,50,98,74,39,26,36,7
data_item3:
.long 95,90,77,34,75,58,39,34,85,34,45,65,45,9
data_items_end:
.equ DATA_SIZE1,data_item2-data_item1
.equ DATA_SIZE2,data_item3-data_item2
.equ DATA_SIZE3,data_items_end-data_item3
.section .text
.globl _start
_start:
movl $data_item1,%ecx
pushl %ecx
pushl $DATA_SIZE1
call max
movl %eax,%edx # %edx holds the maximum
addl $8,%esp # put %esp back
movl $data_item2,%ecx
pushl %ecx
pushl $DATA_SIZE2
call max
addl $8,%esp # set %esp back
cmpl %edx,%eax
jle label
movl %eax,%edx
label:
movl $data_item3,%ecx
pushl %ecx
pushl $DATA_SIZE3
call max
addl $8,%esp # set %esp back
cmpl %edx,%eax
jle end
movl %eax,%edx
end:
movl %edx,%ebx
movl $1,%eax
int $0x80
#PURPOSE:This program finds the maximum number of a set of data items.
#
#VARIABLES:The registers have the following uses:
#
# %edi - Hold the index of the data item being examined
# %esi - Hold that how much ".long" datas there is
# %ecx - Largest data item found now
# %eax - Current data item
# %ebx - The addr of the data
#
.type max,@function
max:
pushl %ebp
movl %esp,%ebp
pushl %edx # save %edx, beacuse it would be used in the MAIN procedure
xor %edx,%edx
movl 12(%ebp),%eax
movl $4,%ebx
idivl %ebx
movl %eax,%esi #the numbers of data is in %esi
movl $0,%edi
movl 16(%ebp),%ebx
[color=#FF0000] movl (%ebx),%ecx[/color]
start_loop:
cmpl %edi,%esi
je exit_loop
incl %edi
[color=#FF0000] movl (%ebx,%edi,4),%eax[/color]
cmpl %ecx,%eax
jle start_loop
movl %eax,%ecx
jmp start_loop
exit_loop:
popl %edx # restore %edx
movl %ecx,%eax
movl %ebp,%esp
popl %ebp
ret
