Hello,
I am trying to write a program that reverses an array with integers. Here is what I have so far:
driver.asm
# Test driver for reverser.asm
#
.data
tsize: .word 10
tdata: .word 2, 3, 5, 7, 11, 13, 17, 19, 23, 29
.text
main:
la $a0, tdata # $a0 points to tdata[0]
lw $a1, tsize # $a1 equals number of elements in tdata[]
jal reverser # call procedure reverser
li $v0, 10 # terminate program
syscallAnd now for my reverser.asm
.globl reverser
# Pre:
# $a0 is not null, $a0 points to list[0]
# $a1 equals number of elements in list[]
# Post:
# $a0 points to list[0]
# $a1 equals number of elements in list[]
# Elements in list[] are now in reversed order.
#
reverser:
# modify nothing above this line
move $t0, $a0
li $s0, 0 # left pointer
addi $s1, $a1, -1 # right pointer value
li $t3, 4 # word size
loop: bge $s0, $t0, done
mul $t1, $t1, $t3 # multiply the left pointer value by 4 to be able to refer to it
mul $t2, $t2, $t3 # multiply the right pointer value by 4 to be able to refer to it
sw $a0, $s2($t0) # insert the left pointer value into the right pointer value in the oriignal array
sw $a0, $s3($t0) # insert the right pointer value into the left pointer value in the original array
addi $s0, $s0, 1 # increment the left pointer
addi $s1, $s1, -1 # decrement the right pointer
done:
# modify nothing below this line
jr $raHowever, I am getting an error for lines 24 and 25:
sw $a0, $s2($t0) # insert the left pointer value into the right pointer value in the oriignal array
sw $a0, $s3($t0) # insert the right pointer value into the left pointer value in the original arrayError is that the operand is not of correct type. Why wouldn't $s2 and $s3 work? They store integers.
Also, is my algorithm correct? If not, how can I possibly use bitshift operators to reverse an array?
Any help is appreciated...
Thank you,