.data
p: .asciiz "Il numero è palindromo"

.text
.globl main
.ent main
main:
addiu $sp, $sp, -4
sw $ra, ($sp)

li $a0, 4
li $a1, 3
li $a2, 2
li $a3, 1
jal determinante2x2

lw $ra, ($sp)
jr $ra
.end main

.ent determinante3x3
determinante3x3
# crea frame
sub $sp, $sp, 4
sw $fp, ($sp)
move $fp, $sp

# salva i registri
sub $sp, $sp, 24
sw $s0, ($sp)
sw $s1, 4($sp)
sw $s2, 8($sp)
sw $s3, 12($sp)
sw $s4, 16($sp)
sw $ra, 20($sp)

move $s0, $a0
move $s1, $a1
move $s2, $a2
move $s3, $a3

# calcolo step 1
lw $a0, 20($fp)
lw $a1, 16($fp)
lw $a2, 8($fp)
lw $a3, 4($fp)
jal determinante2x2
mul $s4, $v0, $s0

# calcolo step 2
move $a0, $s3
lw $a1, 16($fp)
lw $a2, 12($fp)
lw $a3, 4($fp)
jal determinante2x2
mul $t0, $v0, $s1
addu $s4, $s4, $t0

# calcolo step 3
move $a0, $s3
lw $a1, 20($fp)
lw $a2, 12($fp)
lw $a3, 8($fp)
jal determinante2x2
mul $t0, $v0, $s2
addu $v0, $s4, $t0

# ripristina i registri
lw $s0, ($sp)
lw $s1, 4($sp)
lw $s2, 8($sp)
lw $s3, 12($sp)
lw $s4, 16($sp)
lw $ra, 20($sp)
lw $fp, 24($sp)
addi $sp, $sp, 28

jr $ra
.end determinante3x3

.ent determinante2x2
determinante2x2:
mul $t0, $a0, $a3
mul $t1, $a1, $a2
sub $v0, $t0, $t1
jr $ra
.end determinante2x2