Functions and Stacks in Mips #watch in 1080p for maximum learning ;)

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# Tutorial by Ruvim
# about functions and stacks in mips assembly language

# to push into stack
# increase the size of the stack
#load our data into the stack

# get data from stack pointer
# load data from the stack to whatever register we want
# decrease the size of the stack by adding the amount we need to decrease by.

.text

main: nop

li $v0, 4 #loads 4 into v0, 4 means print statement
la $a0, test # prints our test string below
syscall

jal function

li $v0, 4 #loads 4 into v0, 4 means print statement
la $a0, test # prints our test string below
syscall

li $v0, 10
syscall

function: nop

############################## save current ra
# need to push to the stack
sub $sp , $sp, 4
sw $ra, ($sp)
###############################

li $v0, 4 #loads 4 into v0, 4 means print statement
la $a0, func # prints our func string below
syscall

# calls the inner function
jal innerFunc

############## retrieve the correct RA needed
# need to pop the stack and store the value into current ra
lw $ra, 0($sp)
addi $sp, $sp , 4
#############################

jr $ra

innerFunc: nop

############################## save current ra
# need to push to the stack
sub $sp , $sp, 4
sw $ra, ($sp)
###############################

li $v0, 4 # loads 4 into v0, a 4 in v0 means print statement
la $a0, inner # prints out string, see below
syscall

############## retrieve the correct RA needed
# need to pop the stack and store the value into current ra
lw $ra, 0($sp)
addi $sp, $sp , 4
#############################

jr $ra

.data
#random test strings
test: .asciiz " \n This is a test string \n "
func: .asciiz "\n inside the first function \n"
func2: .asciiz "\n still inside function \n"
inner: .asciiz "\n we are in the inner function now \n"