所以我的大部分代码都在工作,但是我无法弄清楚如何处理输入句子长度未知的事实.我是装配新手,这有点令人困惑.
(现在我把它设置为好像长度已知为三个字符,但显然我需要改变它.)
.data
input_msg: .ascii "Enter a random sentence: "
input_msg_len: .long 25
input_str: .ascii "???" # 3rd should get newline
count: .long 0
newline: .long 10
.text
.global _start
_start:
# prompt for input
mov $4, %eax # prompt for input
mov $1, %ebx
mov $input_msg, %ecx
mov input_msg_len, %edx
int $0x80
# get input
mov $3, %eax # 3 to request "read"
mov $0, %ebx # 0 is "console" (keyboard)
mov $input_str, %ecx # input buffer addr
mov $3, %edx # number of symbols typed in
int $0x80 # Go do the service!
again1:
mov $input_str, %ecx
add count, %ecx # count is offset from input_str beginning
mov $4, %eax # to write
mov $1, %ebx # to console display
mov $1, %edx # 1 byte to write
int $0x80 # Do it!
push %ecx # push onto stack
incl count # increment count
cmp $3, count # compare lengths
jnz again1 # jmp again if not 0 (no difference)
mov $0, %edi # use edi as loop counter
mov $4, %eax # print out msg
mov $1, %ebx # etc.
mov $1, %edx # length
int $0x80 # OS, serve!
again2:
pop %ecx
mov $4, %eax # print out msg
mov $1, %ebx # etc.
mov $1, %edx # length
int $0x80 # OS, serve!
inc %edi # increment edi
cmp count, %edi # compare lengths
jnz again2 # jmp again if not 0 (no difference)
# print newline
mov $4, %eax # print out msg
mov $1, %ebx # etc.
mov $newline, %ecx # addr
mov $1, %edx # length
int $0x80 # OS, serve!
# exit
mov $1, %eax # exit
int $0x80 # OS, serve!
基本上,我想知道的是如何让代码适用于任何句子,而不仅仅是一个3个字符？