Lab 06, Complete

Labs/Lab06/Makefile

-all: collatz
-CC=gcc
-CFLAGS=-Wall -Werror
+CC     = gcc
+CFLAGS = -g -Wall -Werror
+EXE    = collatz
+all: $(EXE)
 
 collatz: collatz.o
-	$(CC) $(CFLAGS) collatz.o -o collatz
+<tab>$(CC) -o collatz collatz.o
+
+collatz.o: collatz.c
+<tab>$(CC) $(CFLAGS) -c collatz.c -o collatz.o

Labs/Lab06/collatz.s

+# Student name: Kyle Chrysler
+
+#
+
+#
+
+# This program uses two different procedures, collatz and find length, to compute the 
+# Collatz procedure. 
+#
+
+.data
+	printString: .asciz " ==> "
+	ivar: .word 1
+	return: .asciz "\n"
+
+.text
+
+main:
+	li s1, 100 #Max values
+	la t1, ivar #Keep track of i variable
+	lw s2, 0(t1)
+	jal loop
+
+loop:
+	beq s2, s1, exit #If it reaches max value, go to exit condition
+	mv a0, s2 #Move i to be printed
+	li a7, 1
+	ecall
+	la a0, printString
+	li a7, 4
+	ecall
+	mv s4, s2 #s4 is value used in find length computations (n)
+	j findlength
+	
+back:
+	mv a0, s3 #storing count in a0 to be printed
+	li a7, 1
+	ecall
+	la a0, return #printing a new line
+	li a7, 4
+	ecall
+	addi s2, s2, 1 #increment i
+	j loop
+	
+findlength:
+	li t0, 1
+	li s3, 1
+	bgt s4, t0, while #jump to while if your n is not 1
+	
+while:
+	li t0, 1
+	ble s4, t0, back #if n is 1, return and print it out
+	addi s3, s3, 1 #increment our count since it was not 1
+	j collatz
+	
+collatz:
+	li t3, 0
+	li t1, 1
+	li t2, 2
+	beq s4, t1, one #jump to my condition where n is one
+	rem t4, s4, t2 #check remainder of n
+	beq t4, t3, even #jump to even case
+	beq t4, t1, odd	#jump to odd case
+		
+one:
+	li s4, 1 #make n value 1
+	j back
+	
+
+even:
+	li t0, 2
+	div s4, s4, t0 #divide current n value by 2
+	j while
+
+odd:
+	li t0, 3
+	mul t1, s4, t0 #compute 3n
+	addi s4, t1, 1 #compute 3n+1
+	j while
+		
+exit:
+	li a7, 10
+	ecall
+	
\ No newline at end of file

Labs/Lab06/xfind.s

@@ -125,7 +125,7 @@ main:
 
 # call to xfind
 	
-	li      a7, 34
+	li      a7, 34 #printing out hex value
 	
 	ecall
 	
@@ -143,14 +143,14 @@ xfind:
 	# if found, return the address of the first match
 
 	# if not found, return 0 (NULL)
-	lb t2, 0(a0)
-	beq t2, a1, exit
-	beq t2, zero, exitNull
-	addi a0, a0, 1
+	lb t2, 0(a0) #load the first character of the string into t2
+	beq t2, a1, exit #branch if the character is found
+	beq t2, zero, exitNull #branch if we reach the end of the string (null character)
+	addi a0, a0, 1 #increment to next character in string
 	j xfind
 
 exitNull:
-	li a0, 0
+	li a0, 0 #load null character (0) into 
 exit:
-	jr ra
+	jr ra #return to original function call