系统功能调用实现简单输入输出(mips)

摘要: mips汇编

系统功能调用实现简单输入输出

实验目的：熟悉MIPS的指令，掌握简单的汇编程序结构。

实验内容：利用系统功能调用从键盘输入，转换后在屏幕上显示，具体要求如下：

(1) 如果输入的是字母（A~Z，不区分大小写）或数字（0~9），则将其转换成对应的英文单词后在屏幕上显示，对应关系见下表

(2) 若输入的不是字母或数字，则在屏幕上输出字符“*”

(3) 每输入一个字符，即时转换并在屏幕上显示，需考虑显示结果的清晰美观

(4) 支持反复输入，直到按？键结束程序

(5) 程序结束时，在屏幕上显示本人的姓名全拼和学号

例：在键盘上输入“U2011/”，对应输出内容为“Uniform two zero one one *”

A	Alpha	N	November	1	one
B	Bravo	O	Oscar	2	two
C	Charlie	P	Papa	3	three
D	Delta	Q	Quebec	4	four
E	Echo	R	Romeo	5	five
F	Foxtrot	S	Sierra	6	six
G	Golf	T	Tango	7	seven
H	Hotel	U	Uniform	8	eight
I	India	V	Victor	9	nine
J	Juliet	W	Whisky	0	zero
K	Kilo	X	X-ray
L	Lima	Y	Yankee
M	Mike	Z	Zulu

.data
myname:.asciiz "\r\nNAME:locusxt\r\n"
id:	.asciiz "ID:locusxt\r\n"
aa:	.asciiz "Alpha " #以下是字母对应的字符串
bb:	.asciiz "Bravo "
cc:	.asciiz "Charlie "
dd:	.asciiz "Delta "
ee:	.asciiz "Echo "
ff:	.asciiz "Foxtrot "
gg:	.asciiz "Golf "
hh:	.asciiz "Hotel "
ii:	.asciiz "India "
jj:	.asciiz "Juliet "
kk:	.asciiz "Kilo "
lll:	.asciiz "Lima "
mm:	.asciiz "Mike "
nn:	.asciiz "November "
oo:	.asciiz "Oscar "
pp:	.asciiz "Papa "
qq:	.asciiz "Quebec "
rr:	.asciiz "Romeo "
ss:	.asciiz "Sierra "
tt:	.asciiz "Tango "
uu:	.asciiz "Uniform "
vv:	.asciiz "Victor "
ww:	.asciiz "Whisky "
xx:	.asciiz "X-ray "
yy:	.asciiz "Yankee "
zz:	.asciiz "Zulu "
zero:	.asciiz "zero "    #以下是数字对应的单词
one:	.asciiz "one "
two:	.asciiz "two "
three:	.asciiz "three "
four:	.asciiz "four "
five:	.asciiz "five "
six:	.asciiz "six "
seven:	.asciiz "seven "
eight:	.asciiz "eight "
nine:	.asciiz "nine "
star:	.asciiz "* "
alphabet: .word aa, bb, cc, dd, ee, ff, gg, hh, ii, jj, kk, lll, mm, nn, oo, pp ,qq, rr, ss, tt, uu, vv, ww, xx, yy, zz
num:	 .word zero, one, two, three, four, five, six, seven, eight, nine

backspace:	.asciiz "\b"

.text
.globl main
main:
li $s0, 'z'
li $s1, 'a'
li $s2, 'Z'
li $s3, 'A'
li $s4, '9'
li $s5, '0'

getKey:
li $v0, 12
syscall

#addi $t0, $v0, 0

#la $a0, backspace
#li $v0, 4
#syscall

#addi $v0, $t0, 0

compare:

li $t0, '?'
beq $v0, $t0, deal

#判断是不是小写字母
slt $t0, $s0, $v0 #s0 < v0 ?
bne $t0, $0, dispstar
slt $t0, $v0, $s1 #v0 < s1 ?
beq $t0, $0, dispalph

#判断是不是大写字母
slt $t0, $s2, $v0
bne $t0, $0, dispstar
slt $t0, $v0, $s3
beq $t0, $0, dispalphc

#判断是不是数字
slt $t0, $s4, $v0
bne $t0, $0, dispstar
slt $t0, $v0, $s5
beq $t0, $0, dispnum

j dispstar

dispalphc:#大写字母+32变小写
addi $v0, $v0, 32
dispalph:#处理字母
sub $v0, $v0, $s1 #v0 -= 'a'
sll $v0, $v0, 2
la $t0, alphabet
add $t0, $t0, $v0
lw $a0, ($t0)
li $v0, 4
syscall
j getKey
dispnum:#处理数字
sub $v0, $v0, $s5 #v0 -= '0'
sll $v0, $v0, 2
la $t0, num
add $t0, $t0, $v0
lw $a0, ($t0)
li $v0, 4
syscall
j getKey

dispstar:
la $a0, star
li $v0, 4
syscall
j getKey

deal:#处理问号
la $a0, myname
li $v0, 4
syscall
la $a0, id
li $v0, 4
syscall

==================

syscall 里好像没有不回显的从键盘读

输出"退格"也是不行的,好像直接输出了个空格.

也有可能是mars模拟器太弱了.

这里以及另外一道的esc结束，都替换成了'？'结束