第一次互评作业：用系统功能调用实现简单输入输出 

  1 .data
  2 
  3 string1: .asciiz "*\n"
  4 
  5 
  6 bstring:    .asciiz      #大写字母转换的字符串下同
  7             "Alpha ","Bravo ","China ","Delta ","Echo ","Foxtrot ",
  8             "Golf ","Hotel ","India ","Juliet ","Kilo ","Lima ",
  9             "Mary ","November ","Oscar ","Paper ","Quebec ","Research ",
 10             "Sierra ","Tango ","Uniform ","Victor ","Whisky ","X-ray ",
 11             "Yankee ","Zulu "
 12 
 13 boffset:    .word             #为了得到大写字母字符串数组的偏移量下同
 14             0,7,14,21,28,34,43,49,56,63,71,
 15             77,83,89,99,106,113,121,131,
 16             139,146,155,163,171,178,186
 17 
 18 
 19 nstring:    .asciiz
 20             "zero ", "First ", "Second ", "Third ", "Fourth ",
 21             "Fifth ", "Sixth ", "Seventh ","Eighth ","Ninth "   
 22 
 23 noffset:    .word
 24             0,6,13,21,28,36,43,50,59,67
 25 
 26 
 27 sstring:    .asciiz
 28             "alpha ","bravo ","china ","delta ","echo ","foxtrot ",
 29             "golf ","hotel ","india ","juliet ","kilo ","lima ",
 30             "mary ","november ","oscar ","paper ","quebec ","research ",
 31             "sierra ","tango ","uniform ","victor ","whisky ","x-ray ",
 32             "yankee ","zulu "         
 33 
 34 soffset:    .word
 35             0,7,14,21,28,34,43,49,56,63,71,
 36             77,83,89,99,106,113,121,131,
 37             139,146,155,163,171,178,186
 38 
 39 
 40 
 41 .text
 42 
 43 loop:
 44 
 45 li $v0,12         #读字符
 46 syscall
 47 
 48 move $t2,$v0
 49 
 50 move $t0,$t2             #如果是'?'就退出
 51 li $t1,63
 52 beq $t0,$t1,exit
 53 
 54 move $t0,$t2        #其他符号打印'*'
 55 li $t1,122
 56 bgt $t0,$t1,other
 57 
 58 move $t0,$t2
 59 li $t1,48
 60 blt $t0,$t1,other
 61 
 62 move $t0,$t2        #打印数字对应的字符串
 63 li $t1,57
 64 ble $t0,$t1,number
 65 
 66 move $t0,$t2
 67 li $t1,65
 68 blt $t0,$t1,other
 69 
 70 move $t0,$t2        #打印大写字母对应的字符串
 71 li $t1,90
 72 ble $t0,$t1,big
 73 
 74 move $t0,$t2
 75 li $t1,97
 76 blt $t0,$t1,other
 77 
 78 #print Lower case letters
 79 
 80 addi $t0,$t0,-97
 81 la $t1,soffset                 
 82 sll $t0,$t0,2             #整型数组的下一个偏移量是+4所以左移2下同
 83 add $t0,$t0,$t1
 84 lw $t1,($t0)              #取到对应的偏移量下同
 85 la $t0,sstring
 86 add $t0,$t0,$t1           #算出对应字符串的地址下同
 87 move $a0,$t0 
 88 li $v0,4
 89 syscall
 90 j loop
 91 
 92 other:
 93 
 94 la $a0,string1
 95 li $v0,4
 96 syscall
 97 j loop
 98 
 99 number:
100 
101 addi $t0,$t0,-48
102 la $t1,noffset
103 sll $t0,$t0,2
104 add $t0,$t0,$t1
105 lw $t1,($t0)
106 la $t0,nstring
107 add $t0,$t0,$t1
108 move $a0,$t0
109 li $v0,4
110 syscall
111 j loop
112 
113 #print Upper case letters
114 big:
115 
116 addi $t0,$t0,-65
117 la $t1,boffset
118 sll $t0,$t0,2
119 add $t0,$t0,$t1
120 lw $t1,($t0)
121 la $t0,bstring
122 add $t0,$t0,$t1
123 move $a0,$t0
124 li $v0,4
125 syscall
126 j loop
127 
128 exit:
129 
130 li $v0,10
131 syscall

第一题的算法文字描述:

 

调用系统功能输入数据

转换数据

(1) 如果输入的是字母（A~Z，区分大小写）或数字（0~9），则将其转换成对应的英文单词

(2) 若输入的不是字母或数字，转换成“*”，

每输入一个字符，即时转换并在屏幕上显示，

支持反复输入，直到按“?”键结束程序。

对应的伪码:

 

 1 if(n<=122)
 2     if(n>=48)
 3         if(n<=57)
 4             goto number
 5         if(n<65)
 6             goto '*'    
 7         else
 8             if(n<=90)
 9                 goto big
10             if(n<97)
11                 goto '*'     
12             if(n>=97)
13                 goto small    
14     else
15         goto '*'
16 else
17     goto '*'

 



 

 

posted @ 2017-07-13 12:21  lan126  阅读(722)  评论(0)  编辑  收藏  举报