MIPS 中的冒泡排序

Question

我正在尝试使用冒泡排序对 MIPS 中的整数数组进行排序，但每次运行冒泡排序时都会出现地址超出范围错误。我已经盯着代码看了好几个小时了，不知道为什么会发生这种情况。希望这是非常明显的事情，有更多经验的人可以看到并帮助我解决。 该程序的要点只是读取整数和符号（股票价格和股票代码），然后根据价格对它们进行排序。这是代码：

.data
welcome:    .asciiz "Welcome!\n"
prompt1:    .asciiz "Enter how many stocks you have.\n >"
prompt2:    .asciiz "Enter the four character NASDAQ abbrevation and price for each stock.\n"
prompt3p1:  .asciiz "You have entered "
prompt3p2:  .asciiz " stock abbreviations and prices. How many stocks do you want to buy:\n"
prompt4:    .asciiz "How many stocks do you want to sell:\n"
InfoPrompt: .asciiz "Here are the symbols and the corresponding numbers that were entered: \n"
numStocks:  .word 0
stockPrice: .space 40   # this will be the list of the stock prices
stockSymbol:    .word 0:20  # this will be for the lit of stock abbrevs
symbols:    .space 12   #this should be used for a 40 character array
inputFormat:    .asciiz "\n> "
length: .word 0
buffer: .space 4
.globl main
.text

main: # display all of the propts

    li $v0, 4   # get ready to print welcome
    la $a0, welcome
    syscall     # print welcome

    li $v0, 4   # not sure this is necessary since it was already loaded into v0 before
    la $a0, prompt1
    syscall     # print("enter how many stocks you have.")

    li $v0, 5   # this will get ready to accept the number of stocks
    syscall     # this should store the number into the $v0 register
    sw $v0, numStocks   # store in memory so we dont lose it 
    move $t0, $v0       # this will hold the num of stocks
    #before we go into the procedure we need to declare and move the stack for the $t registers.
    la $t1, symbols
    la $t2, stockPrice
    sub $sp, $sp, 8
    sw $t1, 0($sp)
    sw $t2, 4($sp)
    jal getInfo
    # now that we have all the information lets run a test to see how successful we were
    # jal printInfo
    li $v0, 4   #get ready to ask how many items you want to buy
    la $a0, prompt3p1
    syscall
    li $v0, 1
    lw $a0, numStocks   # prints the number of stocks in the portfolio
    syscall
    li $v0, 4
    la $a0, prompt3p2       
    syscall
    # we need to now get the number of stocks the person wants to buy
    li $v0, 4
    la $a0, inputFormat
    syscall     #format the next input
    li $v0, 5
    syscall
    move $t3, $v0   # the number of stocks we want to buy is now stored as $t3
    #we need to get how many they want to buy
    li $v0, 4
    la $a0, prompt4
    syscall
    li $v0, 4
    la $a0, inputFormat
    syscall     #format the next input
    li $v0, 5
    syscall
    move $t4, $v0   # the number of stocks that you want to sell
    # now we have to sort the list to figure out what elements we are going to sell and buy
    la $a2, stockPrice
    la $a0, stockPrice
    la $a1, numStocks
    jal buble_sort
    jal printInfo
    # end program
        li      $v0,10          #load the syscall number for terminating
        syscall                 #terminate
####################################################################
#   This will iterate for the number of stocks  
#   Only accepts the number of stocks
####################################################################
getInfo:    
    sub $sp, $sp, 8
    sw $ra, 0($sp)  # store the return value
    sw $t0, 4($sp)  # Save the t registers that we will be using
    li $v0, 4 # set up the first call to initialize the calls for the abbreviations and numbers 
    la $a0, prompt2
    syscall
    # we want to have a place to store the symbols
            la $t1, symbols
            la $t2, stockPrice  
GI_loop:
    beq $t0, $zero, GI_loop_done    # if the counter == 0 then we are done
    li $v0, 4
    la $a0, inputFormat
    syscall     #format the next input
    # ask for the string input
    li $v0, 8
    la $a0, 0($t1)
    li $a1, 6
    syscall
    #store the value in the array
    addi $t1, $t1, 6        #increment our "array"
    # ask for the integer input
    li $v0, 4
    la $a0, inputFormat
    syscall     #format the next input
    li $v0, 5
    syscall     # get the integer value that we require
    sw $v0, 0($t2)  #store the value
    addi $t2, $t2,4 #increment our counter

    addi $t0, $t0, -1   # decrement our counter
    j GI_loop
GI_loop_done:
    lw $ra, 0($sp)
    lw $t0, 4($sp)
    lw $t1, 8($sp)
    lw $t2, 12($sp)
    add $sp, $sp, 8
    jr $ra  
####################################################################
#   This will go through the lists and print out what was stored
#   will go through the symbols then the numbers
####################################################################
printInfo:
    sub $sp, $sp, 12
    sw $ra, 0($sp)
    sw $t0, 4($sp)  # this will store the number of stocks that were entered
    sw $t1, 8($sp)
    li $v0, 4
    la $a0, InfoPrompt
    syscall
    # we know that $t0 stores the correct number that was originally enetered so we need to loop through and print all the integers
InfoLoop:
    beq $t0, $zero, InfoLoopDone    # a basic counter check
    #li $v0, 4
    #la $a0, 0($t1)
    #syscall
    #addi $t1, $t1, 6
    #addi $t0, $t0, -1
    #j InfoLoop
    ################################### INTEGER PRINT WORKING
    li $v0, 1           # this will print out the integers 
    lw $a0, 0($t2)          # we have to load the world that is found in the address of $t2
    syscall
    addi $t2,$t2, 4 # this will increment the array 
    addi $t0, $t0, -1   ## this will fix our counter
    j InfoLoop
InfoLoopDone:
    lw $ra, 0($sp)
    lw $t0, 4($sp)
    add $sp, $sp, 8
    jr $ra
################################
# BUBBLE SORT
################################
buble_sort:
#a0=address of table
#a1=sizeof table
add $t0,$zero,$zero #counter1( i )=0

loop1:
addi $t0,$t0,1 #i++
bgt $t0,$a1,endloop1 #if t0 > a1 break;

add $t1,$a1,$zero #counter2=size=6
loop2:

bge $t0,$t1,loop1 #j < = i

#slt $t3,$t1,$t0
#bne $t3,$zero,loop1

addi $t1,$t1,-1 #j--

mul $t4,$t1,4 #t4+a0=table[j]
addi $t3,$t4,-4 #t3+a0=table[j-1]
add $t7,$t4,$a2 #t7=table[j]
add $t8,$t3,$a2 #t8=table[j-1]
lw $t5,0($t7)
lw $t6,0($t8)

bgt $t5,$t6,loop2

#switch t5,t6
sw $t5,0($t8)
sw $t6,0($t7)
j loop2

endloop1:
jr $ra

Answer 1

您的问题出在调用冒泡排序例程之前的声明中：

    la $a1, numStocks

它将加载保存股票数量的地址，而不是股票数量本身。

你应该改变它

    lw $a1, numStocks