MIPS/Assembly

Figure out what number is being returned by mystery function by examining $v0 or printing it out using putDec as in this lab.

Q3. What is the C equivalent code?

Q4. What is printed as the result of mystery(7)?

Q5. What is printed as the result of mystery(32)?

Now that you figured out the actual function of mystery, rewrite it so it obeys all the proper register conventions.

.text

main:

li $a0, 0

jal putDec

li $a0, ' '

li $v0, 11

syscall

li $a0, 1

jal putDec

li $a0, ' '

li $v0, 11

syscall

li $a0, 196

jal putDec

li $a0, ' '

li $v0, 11

syscall

li $a0, -1

jal putDec

li $a0, ' '

li $v0, 11

syscall

li $a0, -452

jal putDec

li $a0, ' '

li $v0, 11

syscall

li $a0, 2

jal mystery

move $a0, $v0

jal putDec

li $a0, ' '

li $v0, 11

syscall

li $a0, 3

jal mystery

move $a0, $v0

jal putDec

li $a0, ' '

li $v0, 11

syscall

li $v0, 10 # terminate program

syscall

putDec:

## FILL IN ##

jr $ra # returnv

mystery: bne $0, $a0, recur #

li $v0, 0 #

jr $ra #

recur: sub $sp, $sp, 8 #

sw $ra, 4($sp) #

sub $a0, $a0, 1 #

jal mystery #

sw $v0, 0($sp) #

jal mystery #

lw $t0, 0($sp) #

addu $v0, $v0, $t0 #

addu $v0, $v0, 1 #

add $a0, $a0, 1 #

lw $ra, 4($sp) #

add $sp, $sp, 8 #

jr $ra #