Using bit shifting to perform multiplication

I am trying to use Mips Mars to create assembly code that uses bit shifting and a loop to multiply any number up to 32 bits. But it is only iterating twice if that.

I have already gotten the multiplier and multiplicand earlier in the program.

$t0 = multiplicand

$t1 = Multiplier

#Multiply operation
li $t3 0 #Counter
li $t4 0 #result
li $t6 0x80000000
myLoop:
    bgt $t3, 31, showMessage

    addi $t3, $t3, 1 #Keep track of counter $t3
    andi $t7, $t1, 1 #Find lsb of multiplier
    andi $t8, $t6, 1 #Find LSB $t6
    and $t5, $t8, $t7 #And LSB of multiplier and lsb $t6
    sll $t6, $t6, 1 #shift $t6 right 1
    srl $t1, $t1, 1 #Shift multiplier right 1


    blez $t7, myLoop
    add $t4, $t0,0  #Result

    sll $t0, $t0, 1 #Shift multiplicand left one
    j myLoop

I expect the output of 4*3 to be 12 but it is 8.