CODEWITHSUNDEEP
c++assemblymips
Omie
Omie

Reputation: 5

Translate C++ to MIPS Assembly

I need help with this last part of this problem. I'm basically trying to translate C++ code into MIPS Assembly language.

Assume a is in $s0, b in $s1, c in $s2, x in $s4, y in $s5, and z in $s6.

I finished almost all of them but I am stuck on these two, I know some parts of it but I'm having trouble putting it together as a whole. The parts I know will be followed by hashtags with the assembly code. Thanks for any help.

1.

for(x = 0; x <= z; x++) # x = 0; is: addi $s4, $0, 0
y = y + 1; # addi $s5, $s5, 1
y = 0; # addi $s5, $0, 0

2.

if(y > z)
x = 0; # addi $s4, $0, 0
else x = 1; # else: addi $s4, $0, 1

Here are the oringinal problems without the hashtags incase I am wrong:

1.

for(x = 0; x <= z; x++) 
y = y + 1; 
y = 0;

2.

if(y > z) 
x = 0; 
else x = 1;

Thanks again.

Attempt at 2, not sure if right.

ifLoop:

add $s5, ? , $s6
addi $s4, $0, 0

ifLoop

else:

addi $s4, $0, 1

else

Practice: (Assume array p is in $s7)

p[0] = 0; 
int a = 2; 
p[1] = a; 
p[a] = a;

My attempt:

sw $0, 0($s7) 
addiu $s0, $0, 2 
sw $s0, 4($s7) 
sll $t0, $s0, 2 
addu $t1, $t0, $s7 
sw $s0, 0($t1)

Upvotes: 1

Views: 5112

Answers (1)

Inertiatic
Inertiatic

Reputation: 1270

Edit: 1. Luckily it is not much different without pseudo instructions. 

addi $s4, $0, 0

forLoop: sle $t1, $s4, $s6  #if x <= z, set $t1 to 1, else 0
         addi $s5, $s5, 1
         addi $s5, $0, 0
         addi $s4, $s4 1
         bne $t1, $0, forLoop #repeat loop while $t1 is not 0

Here is #2. I just wanted for you to give it a go before I just gave the answer. You want to use the slt instruction to set a register to 1 or 0. If 1, the comparison is true (y > z). Then use bne to determine where to jump to. By comparing the bne to 0, the true code ends up being directly below the bne instruction. For the else, jump to the label.

slt $t2, $s6, $s5 # if z < y, set $t2 to 1, else 0
bne $t2, $0, else # if $t2==1, do the code below, if not, go to else

        addi $s4, $0, 0
        j continue    # need the jump instruction to skip the else below
else: 
        addi $s4, $0, 1

continue:
        # rest of code/program

Upvotes: 1

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