diff --git a/mips.html.markdown b/mips.html.markdown
index 27a11e2f..9b176842 100644
--- a/mips.html.markdown
+++ b/mips.html.markdown
@@ -200,7 +200,8 @@ hello_world .asciiz "Hello World\n" # Declare a null terminated string
## LOOPS ##
_loops:
- # The basic structure of loops is having an exit condition and a jump instruction to continue its execution
+ # The basic structure of loops is having an exit condition and a jump
+ instruction to continue its execution
li $t0, 0
while:
bgt $t0, 10, end_while # While $t0 is less than 10, keep iterating
@@ -220,7 +221,7 @@ hello_world .asciiz "Hello World\n" # Declare a null terminated string
# Do stuff
- addi $t1, $t1, 1 # Increment the col counter
+ addi $t1, $t1, 1 # Increment the col counter
matrix_col_end:
# Do stuff
@@ -228,4 +229,63 @@ hello_world .asciiz "Hello World\n" # Declare a null terminated string
addi $t0, $t0, 1
matrix_row_end:
+## FUNCTIONS ##
+ _functions:
+ # Functions are callable procedures that can accept arguments and return
+ values all denoted with labels, like above
+
+ main: # Programs begin with main func
+ jal return_1 # jal will store the current PC in $ra
+ # and then jump to return_1
+
+ # What if we want to pass in args?
+ # First we must pass in our parameters to the argument registers
+ li $a0, 1
+ li $a1, 2
+ jal sum # Now we can call the function
+
+ # How about recursion?
+ # This is a bit more work since we need to make sure we save and restore
+ # the previous PC in $ra since jal will automatically overwrite on each call
+ li $a0, 3
+ jal fact
+
+ li $v0, 10
+ syscall
+
+ # This function returns 1
+ return_1:
+ li $v0, 1 # Load val in return register $v0
+ jr $ra # Jump back to old PC to continue exec
+
+
+ # Function with 2 args
+ sum:
+ add $v0, $a0, $a1
+ jr $ra # Return
+
+ # Recursive function to find factorial
+ fact:
+ addi $sp, $sp, -8 # Allocate space in stack
+ sw $s0, ($sp) # Store reg that holds current num
+ sw $ra, 4($sp) # Store previous PC
+
+ li $v0, 1 # Init return value
+ beq $a0, 0, fact_done # Finish if param is 0
+
+ # Otherwise, continue recursion
+ move $s0, $a0 # Copy $a0 to $s0
+ sub $a0, $a0, 1
+ jal fact
+
+ mul $v0, $s0, $v0 # Multiplication is done
+
+ fact_done:
+ lw $s0, ($sp)
+ lw $ra, ($sp) # Restore the PC
+ addi $sp, $sp, 8
+
+ jr $ra
+
+
```