CODEWITHSUNDEEP
arraysassemblymips
Michalistico
Michalistico

Reputation: 185

Finding random number on array

I have to create a mips code which it has to tell me if a random number (given by the user) is in the array (1) or its not (0). I have two problems, the first one is that the random number that I´m trying to ask to the user (li $v0, 5 -- syscall -- move $t0, $v0) its not working, in fact it does nothing when I assemble it. The second problem is weird, I have 2 loops (target) and (exit loop), the first one to check if a number is on any of the array position (10 positions) and the second to exit with a 0 if it didn't find the number. Any ideas?

iterator = 4
N = 10
     .data
vector:         .word 2, 3, 5, 6, 8, 1, 3, 2, 5, 9
     .text
main:
    lw $t2, buscador
    li $t1, iterator
    la $s1, vector
    move $s0, $zero

    li $v0, 5
    syscall
    move $t0, $v0

target:
    bgt    $s0, N, exit_loop
    mul $t3, $s0, $t1
    addu $t3, $t3, $s1
    lw $t3, 0($t3)
    addi $s0, $s0, 1
    bne    $t0, $t3, target
    li $s2, 1
    move $a0, $s2
    li $v0, 1
    syscall

exit_loop:
    li $s2, 0
    move $a0, $s2
    li $v0, 1
    syscall

    li $v0, 10
    syscall

Upvotes: 1

Views: 118

Answers (1)

Craig Estey
Craig Estey

Reputation: 33631

There appears to be nothing wrong with your program.

The symbol buscador was not defined, so the program may not have assembled correctly. I commented out the given line. This may have been the only problem.

I did some slight cosmetic cleanup and added some annotations. I also simplified the print integer syscalls [yours would have worked, as is].

I did add an extra jump to a new label exit_program to keep the pass/fail cases separate. Otherwise, you'd have a "fall through" from the pass case to the fail case and you'd get "10" instead of "1" for the pass case.

But, otherwise, I did not (i.e. did not need to) change your logic.

I tested the program and it works on both QtSpim and mars.

Anyway, just to be sure, here's a working version:

    iterator = 4
    N = 10

    .data
vector:     .word       2, 3, 5, 6, 8, 1, 3, 2, 5, 9
    .text

main:
    # NOTE: this symbol was _not_ defined, so spim may have silently not
    # run the program
    ###lw       $t2,buscador
    li      $t1,iterator            # get sizeof(vector[0])
    la      $s1,vector              # get vector base address
    move    $s0,$zero               # set vector index to zero

    # prompt user for number
    li      $v0,5
    syscall
    move    $t0,$v0

target:
    bgt     $s0,N,exit_loop         # vector end? if yes, fly

    mul     $t3,$s0,$t1             # offset = index * iterator
    addu    $t3,$t3,$s1             # current addr = base + offset
    lw      $t3,0($t3)              # fetch word from vector

    addi    $s0,$s0,1               # increment the vector index
    bne     $t0,$t3,target          # does value match? if no, loop

    # value matches -- output a 1
    li      $a0,1
    li      $v0,1
    syscall
    j       exit_program

# we did _not_ find a match -- output a 0
exit_loop:
    li      $a0,0
    li      $v0,1
    syscall

exit_program:
    li      $v0,10
    syscall

Upvotes: 0

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